Hi, I have an intermittent wiring fault with my newly acquired 1980 Louisville LNT 8000. Sometimes the reverse light and the interior cab light stay on for 30 minutes after the truck is switched off. (if I don't use the isolator) And they also switch on when I start her up, most days. There doesn't seem to be a switch for the interior light so I planning on replacing with a newer more modern, more functional light so I'm not really concerned about this one. I would like to install a much more powerful reversing light so I can actually see at night but I'm concerned it might say on and shine into other traffic which could attract police attention to my old truck. Does anyone have a wiring diagram or any tips/advice? Should I just install a new reversing light with a switch so I can turn it on when I need it? I also need to install a reversing buzzer/beeper. I'm worried that this might stay on if I use the current wiring. Thanks! Nick
The switch for the interior light is on the same switch for the headlights, just by turning the knob all the way to the right. As for the lights staying on you must be having power being feed in wrong, drop down the dash panel on the right side and with a test light , see what stays on on the bottom row of wires and then trace that. Also a terminal board behind the passenger seat for power going to rear points of the truck. If your going with a more powerful backup light/alarm,, you may consider installing a relay as I don't believe the backup light switch on the transmission will handle all the extra current flow need to run the extra equipment.
I have a 1980 LN8000. The interior light doesn't have a switch, only the door switch. The headlight switch on mine is a knob on the dashboard near the steering column that you pull out, not turn, and doesn't include an interior light position. There may be some differences between Australian and American models. For example the dash panel on the left side is the one to drop down to check the circuits, and the terminal board is behind the drivers seat. I don't know how the interior light is wired, but if it switches to earth, you may have a short to earth causing the light to be on, or a faulty switch. Anyway as you say you are not too worried about this. I know what you mean about the light not being very functional. Mine has no separate reverse light, instead when you put it in reverse the rear indicator lights both come on. They come on solid, not flashing. It does this by sending power from the reverse light switch on the gearbox, into the indicator/hazard switch on the steering column, which directs it to the indicator lights at the rear. It seems a strange way of doing things but this is standard wiring as it came from brand new. If yours has its own separate reverse light, somebody may have already changed the wiring around and run it direct from the switch on the gearbox, which would make more sense than the standard way. Bear in mind that mine is a LN8000, not a LNT8000, so the wiring may be different, if it is, sorry to confuse things. If the reverse lights are staying on, the first thing I would be looking at is the switch on the gearbox, it might be stuck on. Find the switch on the gearbox, there should be power going into it but not coming out, until you put it in reverse and then there should be power going in and coming out. If there is no change when you select reverse then the switch is stuck. Remember to have the key in the 'on' position. If you plan to set up a brighter reverse light, I would agree with grandpa and wire it up with a relay so that you don't overload the gearbox switch. The only thing wrong with setting up a manual switch to turn on the reverse light, is the possibility of forgetting to turn it off. Although if you have a loud enough reverse beeper you will be able to hear it if you leave it on. Any reverse beeper alarms that I have dealt with use such a small amount of power that you can connect into existing wiring without worrying about overloading the circuit.
Thank you both for your valuable information. Mine does seems to have a fuse box in front of the passenger seat. From what you're saying there is also a terminal box behind the driver seat. My headlight switch pulls out also, just to the right of my steering wheel. I haven't tried twisting it though, I will try it over the weekend. I will also check to see if my door switch works. I will investigate further and double check when the reverse light does come on. It seems quite random at times. It is a separate light but it isn't very bright and certainly not standard. Perhaps they have hooked it into the number plate light circuit?? My biggest question is how to get to the switch on the gearbox?? unless its on the bottom or sides it looks damn near impossible to get in there. I think I can hear an small air leak in there so I have been contemplating it but haven't come up with anything yet. Perhaps I could install an LED reversing light, would that save the trouble of running power down there and a relay? I saw one on ebay (Power:27W,Voltage:10~30VDC) My truck is 12V so it would only pull 2.25 Amps. Would that be ok? If I was to run power to the back end, what gauge wire would I need? Is there somewhere that sells a loom so I could run a few spares for future additions or future failures? I'm toying with the idea of a reversing camera a bit further down the track. Plant Fitter, while I have your ear, what oil do you put in your gear box and diff? I just bought this truck and I'm trying to give it a bit of a birthday. I'm not sure how often the previous owners changed the fluids. I'm also trying to find out which hydraulic oil to put in the tipper hoist. The oil level is quite low so I figure I ay as well change it too rather than topping it and mixing old an new.
To find the reverse light switch, just look for wires going to the gearbox. I don't know where it is actually located but it shouldn't be too hard to find, there won't be much else on the gearbox that has any wires. It probably is up on top or near the top, up near the selectors. You might need a torch and a mirror to see on top. I would think that 2.25 amps would be ok for the reverse light switch. If you buy the light on ebay and it is not a decent brand, you will probably have to buy a decent one soon after. I always use heavier wire than is really needed, so I would probably use a 4mm wire. If you run twin core wire, use 1 wire for power and earth the light to the chassis, then you will have one spare for the future. Another option is to run 7 core trailer cable, this will give you plenty of spares, however you are not likely to need that many spares coming from the gearbox. If you run 7 core cable, in this or at any other time, make sure you get some that is heavier than normal. As yours is a LNT, the transmission and diffs will be different. If its a Road Ranger transmission, it should run on a 50 grade oil. Diffs are probably 85W140. Try the Mobil lubricant website http://www.datateck.com.au/lube/mobil_au/ to see what they recommend. Your local oil supplier might have a website or a hotline that you can call, if you don't use Mobil products.
Im sorry,, I keep forgetting they put the steering wheels on the wrong side for you aussie's.
yeah i know, I'm always afraid to mention it in case you guys don't answer because the steering wheels on the wrong side! Interesting that the terminal you both mentioned is on the same side in both countries! But how do you get in there? do you go from underneath or try to squeeze through the top past the engine? I ended up working all weekend so I haven't really been able to investigate as much as I would have liked but I did discover a few things. The interior light does come on like you said Plant Fitter with the door switch so that's one mystery solved. Now I just need to get some power up there so I can have new light and be able to turn it on when the door is shut. The second thing I discovered is that the "reversing" light comes on when the ignition is switch to ON or ACC. putting it in reverse seems to have no effect at all and doesn't light up the indicators like you mentioned. At this stage I'm think running a new cable from the gearbox would be the way to go. Thank you for the Mobil link, I've been using Castrol and with that info I managed to find a similar link http://www.datateck.com.au/lube/castr_au/ As usual reading through this information has sparked more questions than answers... I have a 15spd road ranger but I'm not sure which diffs I've got. Is there any way to tell? The choices are DIFFERENTIAL - EATON 2-SPEED and DIFFERENTIAL - MERITOR (ROCKWELL) SINGLE & TANDEM AXLES My gear stick has two selectors plus a clutch brake. I think its deep reduction, then low range and high range. I know its not the original gearbox but I don't think that should affect the diffs. Also there is a diff lock. I'm hoping some of that info should help you guys id my diff. While I'm asking questions what do I need to know about a 2-SPEED AXLE SHIFT UNIT RES? Thanks again, you guys are awesome.
Hi guys, New here. The switch is just a ball switch, which means there is a ball bearing that rides on the shift rail in the tranny and drops into a detent in the rail that turns the lights off. These type of switches do get sticky with time. But your switch is most likely on top of the tranny. Which may mean you will have to remove the floor pan, which is the pan your shift levers come through. There should be a half a dozen or so screws that hold it to the floor. On the lighting, If you are going to put some 1 million candlepower loading lights on, then a relay may be required. But, if you are just looking to put brighter back-up (reverse) lights on. I would just go with the Grote or Signal Stat L.E.D.'s that are probably available at your parts supplier. You will have to cut some of your wiring for the lights that are currently on it to connect the new pigtails. The 2spd. rear end gives you part of your deep reduction. Just keep it full of lubricant and make sure the air lines are in good shape. Hope this helps
We both know that our steering wheels are on the right side. Its pretty obvious, right is right, left is wrong. Have a look on the diffs for an ID plate which will tell you the make and model. It may have fallen off by now but still worth a look. A 2 speed differential is for trucks with a single drive axle and 4 or 5 speed transmission, the 2 speed axle gives you twice as many gears. They don't use these with any tandem drive that I have ever seen. As you have a Road Ranger and tandem drive, you won't need to worry about the 2 speed differential. The "2 speed axle shift unit res" is the unit that changes the gear ratio on the 2 speed diff, so you won't need to worry about that either. The diff lock is probably to lock the inter axle differential, which is another diff, inside the first axle, on the output shaft that goes to the second axle, to stop any wind up between the two when turning, or when running different size tyres. So the first drive axle actually has 2 diffs in it.
Thanks 6wheeler, removing the floor pan is something i would't have thought of, I'd trying to squeeze my way in. Those work lights look pretty good. I think LED is the way to go eh. So does that mean I would have the Eaton 2 speed diff? Does that mean I have the Meritor Rockwell diff? I'm a bit confused now. I will get under there and look for an id plate. Perhaps take a photo or two and post them on here. Thank again folks
ok I got a few pics This is the most rear diff, looks like a Rockwell to me. Do I assume that they are both rockwell now? here is the front rear diff if you know what I mean. couldn't find a plate on that one. I found this on my drive shaft, does that look normal to you guys? Sorry for all the questions, this is my first truck... cheers, nick
Picture of the driveshaft looks better than normal..... looks like somebody has greased it at least recently. LOL
I can see Rockwell emblems cast into your "front rear diff" So looks like both Rockwells to me. The driveshaft looks ok as well. A bit of grease around the slip joint is ok. If you keep pumping grease in there it has to come out somewhere. Shake the tailshaft as hard as you can at each end and in the centre to make sure the slip joint and the universals are not loose.
I am not saying that 6 wheeler is wrong, but if you have a deep reduction gear, it is in the gearbox. 2 speed diffs are to give twice as many gears by giving a gear ratio halfway inbetween each standard gear. I've only ever seen, or heard of, 2 speed diffs used with single drive axles, not tandem drives. You don't have a 2 speed diff.
Ok great, Rockwell Diffs. I've ordered some oil for the Diff's. I've changed the diff and gearbox oil in my ute before, is there anything different I need to be aware of? The fill and drain plugs have a square shaped hole. I don't think I have any tools to open them, what would that be called so I don't look silly at the tool shop? Are there any secret filters that need changing when changing these fluids?
Your square shaped holes in the level and drain plugs is probably to fit a 1/2 inch square socket bar with no socket on it. Some diffs have filters but they are on the outside where you can see them. It is more of a modern thing and I doubt that yours will have one. If there looks like there is 2 level plugs, use the high one, the low one will be for a temperature sensor.
They are square to accept a flex handle wrench... ususally 1/2inch or 3/4inch drive. In MM's, I just dunno...lol
This is a side note and not really applicable but I wanted to clear something up: 2 speed rears can be used with tandems just as well as they can with singles. They just apply the air/vacuum/electric to them both at the same time and they shift simultaneously (usually). Mostly applicable to very old trucks now, but very heavy haulers still get them new sometimes. There was also such a thing as a 3 speed where they would allow one axle to be in high and leave the other in low at the same time, but this proved to be destructive to the interaxle differential which was taking up the difference when it was in this intermediate condition so it was not a really good idea. There is always an exception.
I just googled we call that a breaker bar down under, thanks grandpa! Would my 1980 truck fit into this "very old trucks" category? I hope not, I thought I knew what I had!
Thanks Birken Vogt for adding this in. What brand of trucks used these? I presume it was only before range change gearboxes became common? You mentioned they shifted simultaneously usually, what type of destruction was caused if one shifted and the other didn't, while the inter-axle differential was locked? I stand corrected, but like I said I have never seen them other than on a single drive axle.
I found the switch on the gearbox. I think it doesn't work. power goes in but doesn't come out again. are they easily replaced?
If power goes in but doesn't come out, then that won't make your reverse lights stay on. The power would have to be going in and coming out again for the lights to be staying on. Unless they are wired to something else alltogether. Did you test in reverse and not in reverse? To replace simply unscrew from the gearbox. When you have it out, re-test by pushing the switch on and off by hand. If it works then, you may have a worn selector in the gearbox which doesn't move quite far enough to push the switch in. If you decide that it is faulty, take it to your local truck workshop and see if they can find a new one to fit.
Yes agreed. The reverse light comes on with the ignition. I tested in reverse and out of reverse with the key in the on position. I'll try to get it out and test it. Thanks again.
Do you think it might be possible that someone has wired up the reverse light to a manual switch, and you just haven't found it yet? Try following the wires from the reverse light, if it has been wired up separately they will be easy to follow. Just a thought as things don't seem to be adding up.
Well I suppose that is entirely possible, I will go though the old switches and see if I can find it. From what I can tell the reverse light wire goes to that terminal block behind the driver seat. And when I turn the ignition on it gets power from that point. But its a bit harder to see where the wire goes from there... I'll try some switches.
Hey Plant Fitter can I ask you another question? I've noticed that I'm losing coolant and it seems I have no hose or reservoir attached to my radiator overflow. Should there be? where does the reservoir sit in your machine?
Normally there would be a piece of hose about a metre long on the outlet just running down the side of the radiator onto the ground. It doesn't go into any overflow bottle or anything. So it doesn't really do anything other than stop any overflow running down the side of the radiator and making a mess. The best way to check the level is to have a stick of wood handy, remove the cap, put the stick of wood down inside and pull it out to check the level, like a dipstick. The level when cold will seem pretty low. If you have it around 2/3 of the way up the radiator it should be alright. It seems like the radiator is nowhere near full enough but if you fill it up too much it will overflow as soon as it warms up. Because it is a crossflow radiator with the tanks on each side instead of the top and bottom, the rate of expansion seems more pronounced.
Ok thats great to know, I thought I should keep filling it up. there is a little window on the side I figure it should stay about that level perhaps? You have a wealth of knowledge, thanks for sharing!
The window in your photo, that would be too high for the cold coolant level. Fill it up that high when it is cold and it will overflow when it warms up for sure. The windows often get covered with muck on the inside and are best ignored. Use a stick of wood and you will know for sure. Its a bit hard until you get the hang of where it should be which you will work out after you have had it for a while. Too high and it will overflow, but this doesn't do any harm. Too low and you risk overheating.
To give you something to chew on, you could add a coolant recovery bottle. If theres a scrap yard with newer trucks that you can hunt in, you should be able to come up with something. See what kind of space you have to work with, and look around for something you could fit neatly. Might need to make a bracket or two though. You'll also need an radiator cap that will accomodate coolant recovery. Over here, its pretty much the only rad cap you will readily find, but the "old" non-recovery cap won't suck fluid back from the recovery tank. Remember to look at trucks other than ford, the name on the front won't matter, its size and workable shape you are after. Alex.
Thanks Axle, I was thinking about something like that, well I was looking to see where the missing coolant bottle was before I posted. I add this to my list! Cheers
My dad always used to add recovery bottles to his cars and trucks. He simply used a hose into the top of any gallon size antifreeze bottle wired through the handle to some sturdy part of the vehicle. He cut a hole in the screw top or somewhere in the top of the bottle just so tha the hose would fit tightly and go to the bottom. Cut a v-shaped notch in the end of the hose so it can't suck to the bottom of the bottle. It seems a lot of old Fords with a pressurized surge tank also used a non pressurized recovery bottle. I am a fan of having a non pressurized bottle after the pressure cap, as it makes the coolant system totally hydraulic with no air splashing in the coolant from the engine/radiator bleed hoses. It seems air in the coolant leads to metal corrosion or coolant degredation to some degree. If you look at a GMC Duramax, at least the older ones, they have the coolant bleed hoses returning under the water level to prevent this splashing which is the downfall of the Dex-Coool coolant. Not really an issue in your case but just a thought.
They were a bit before my time, too. But I have a very old Eaton (I think) book that describes the tandem system in detail. I don't know where the book is now though. A range change box is far superior, I'm sure you know. A 2 speed rear is basically like a little manual transmission that has a 1st and 2nd gear position. 1st is low and 2nd is direct. There is a little electric motor that drives a worm gear that drives a spring that shifts it, or it might be air or vacuum operated. Say you have it in 1st and you want to be in 2nd. You pull the button up. It starts to pull on the lever but nothing happens as the torque has it all bound up. Same as if you wanted to shift your manual transmission from 1st to 2nd, but have your foot in it still, you can't pull the lever out but you can put tension on it. Now you back off the throttle and it immediately is able to pop the rearend out of the 1st gear and it starts raking the teeth of the 2nd gear dogs. Just like if you are gently trying to feel your way into 2nd gear with your (unsynchronized) manual transmission. When engine (hence drive shaft) RPM drops to match where it needs to be for the 2nd gear, it drops right in. (Usually) -----NOW, with a tandem, both rears will be undergoing the same torque and load conditions so they should release to neutral and start raking the other gear at the same time. If one catches before the other one then the inter axle differential will take up the difference and it will still feel like it is in neutral until the other one catches the new speed. If somehow one comes out and the other doesn't then the IAD will take up the difference and it will drive fine, just be in a little bit of a different range. A quick release of the throttle and making it complete the shift should correct this quickly. The "3-speeds" did this on purpose but it was found to prematurely wear the IAD. I don't think you could ordinarily get one in one range and one in the other range with the IAD locked. The torque between the diffs would already have the 2-speeds bound up so they would never release. If they did release they would do it simultaneously. If one failed to release the other would remain in the raking position unless you came to a stop so you would have single drive. But if somehow it did as you said the mechanical advantage would be pretty bad and it would definitely twist something off I should think. You would not normally shift a 2-speed in conditions that require an IAD to be locked, though, any more than you would shift the button on an 18 speed while you were bogging in the mud, or try to engage a diff lock with the wheels spinning. A 2 speed is for high speed driving.
Thanks for the detailed explanation. Sounds like we should be glad that range change gear boxes were invented.
Yesterday i put my new reverse light and beeper in. I ran new wire all the way from the back to the terminal behind the driver seat and then from there to the dash. I haven't fixed the switch on the gearbox yet so I put a big red light on the dash to remind me to turn them off. I have two switches, the beeper can only come on if the light is on and when the light is on the bog red LED comes on. Later I can replace the power supply with a line from the gearbox when I fix that switch! Also we discussed my diffs further up this page, I noticed while installing the cable that my driveshaft says spicer on it. So I have an Eaton transmission, spicer driver shaft and rockwell diffs. I'm guessing this is pretty normal in the trucking world?
Normal for trucks with American driveline.
Not sure what that thing is in front of the diff, could be a gear reducer, whether it is 2 speed I don't know, is there a lever or hoses going into it? Far as the radiator goes, that would be a header tank and not the actual radiator. The sight glass is the coolant level. You might need a new radiator cap.
The front dif is normal for a Rockwell, the interaxle dif lock is in the bulge on the front.
There is no header tank. The photo is of the actual radiator. What are you talking about?
Ok cool so that lump it the diff lock. thanks Mitch
You may know it as an expansion tank, most radiators do not have the cap on them but rather have it on a separate header/expansion/overflow tank. For instance I used to drive a 70's vintage Inter Acco 3070 which had the header tank mounted behind the cab, this was handy so you didn't have to tilt the cab every day to check the coolant, which on this model was done with a bit of wire cause the tank had no sight glass. Another example is a mid 80's Inter S line which had the header tank under the bonnet but had a sight glass on it so you could check the coolant in a nano second. This is I think a picture of a radiator for an LN8000 http://www.apairinc.com/dealer/detail.asp?part=TR9437 I do not see a radiator cap, however I could be wrong. Also all the radiators I have come across that did not have an expansion tank or have the radiator cap on the radiator, the coolant level is supposed to be within one inch of the top, not down there where the sight glass is. Do you run your radiators 3/4 full?
This is the radiator....when its warm the radiator is full, when its cold, its below the sight glass
The radiator cap on the radiator is very common on american trucks. ( This seems to be just an american truck that they screwed up by putting the steering wheel on the wrong side, so they dumped it in oz) Believe it or not we had a Ford L-something w/ a little short hood and a 3208, that had a sight glass about 7-8 inches below the radiator cap. Everytime somebody would ignore my instructions and fill the radiator, I'd get a paniced call, the truck would be sitting still pumping, running 1800 rpm, and a solid stream of water would be spraying out of the tube below the cap, over the tire. So, yes, on this Ford, I did run the radiator 3/4 full. I never knew why this one experienced so much expansion. I currently have a 1986 GMC Top Kick wrecker w/ a 3208, I run that radiator full.
Hmmnh odd, is it possible that the header tank is incorporated into the radiator, I am wondering why there is a drain valve half way down the radiator?
That old Ford had the drain valve too. I just used it when somebody overfilled it. When you say header tank, you mean a pressurised tank w/ the radiator cap on it, right? Of the last 15 or so trucks I've had, only one didn't have the radiator cap directly on the radiator. Those tanks seem more common on cabovers, but cabovers are rare as hen's teeth here.
Fair enough. Yeah a header/expansion tank is basically an extension of the radiator. The advantage is that the radiator is 100% full all the time, which is handy in Summer. We have a pile of cabovers, mainly K series Kennys and Euro stuff. Very popular for B double work cause of length limits.
I know what a header tank is. This truck just doesn't have one. You may have been mistaken by that it has a crossflow radiator, with the tanks on the side, making you think that the side tank with a cap on the top looked like a header tank. The radiator picture you have found must be for much later models, the Sterlings have a header tank with a cap and a radiator like that. I have always put the supposed high rate of expansion down to it having a cross flow radiator, I had always thought that maybe if you filled a normal radiator to within 1 inch of the top, then turned it on its side, the level would be somewhere like it has to be for these old Louisvilles. This is just my theory, but its the best I can come up with. On second photo showing more of the radiator, if you look on the side of the radiator about halfway between the sight glass and the drain valve, there is a flat spot between the ribs, with 3 ribs above and 2 ribs below. This flat spot is where I have the water level on my LN8000 when it is cold. Any higher and it will overflow when it is hot.
There may be something more to this tank than meets the eye. Internal baffles or something. We used to have a similar looking tank on an F-700 Ford that was a header tank on top of the downflow radiator that looked exactly like a regular radiator top tank except there was no radiator attached to it, only the bleed hoses that went to the radiator and engine top. See how this one has the small hose between the upper heater hose and the side of the upper tank; if that tank was one chamber there would be no need for such a hose. I still recommend putting an extra unpressurized expansion tank on a setup like this because it can't hurt anything and it is sure to keep the radiator chock full at all times. Our current 1990 L-8000 is setup like this from the factory.
Well I have been scratching my head and other parts of my body to try and understand how coolant can expand to such an extend that you can only fill a radiator 3/4 full or it will boil over. However header tanks have to be higher than the radiator as they work on gravity feed. Anyway as long as the old girl don't cook itself when summer comes around.
The little bypass hose has always made me wonder as well. However, the easiest way to check the coolant level is to put a stick down through the filler neck. If you do this, it goes right to the bottom of the side tank, without hitting any baffles or anything like that.
To try to explain my theory, how about this. This is all hypothetical. Forget about any header tanks or overflow bottles. Imagine a regluar truck radiator, with a tank on the top and the bottom. Fill it with water until it is full to the top. Drain out 2 litres. This will leave the level down about 1 inch from the top of the filler neck, which would probably be about right to use. Imagine a similar size truck radiator, only this time it is a cross flow with tanks on the sides. Fill it with water until it is full to the top. Drain out 2 litres. This will leave the level down a lot lower. The amount of water in the tubes is little. The cross section size of each side tank is similar to that of a 1 litre milk carton. So when you drain out the two litres, imagine holding a milk carton next to the side tank, this is how far the level will have dropped for the same amount of water. Its the same amount of water, it just seems more. Does this make sense?