I have a 980G that has been getting lots of coolant in the transmission after starting it this spring. I have a new trans cooler on the way. I removed the cooler today and pressure tested it-more to see where it was leaking than anything else. Anyway to cut a long story short it looks like the cooler is not leaking,(pressurised it to 30 psi). Can anyone tell me if there is anywhere else that the coolant can get into the trans oil?
The only place that coolant and oil should get close to each other is in the cooler. How much is lots? Might be that the cooler only leaks when it is hot? Are you putting pressure on the coolant side or the oil side? Should not make a difference but..... I'm assuming you have ruled out error or vandalism ? Also not to sound stupid but you did remove and test the correct cooler? Any chance of a S/N just to let one check in more detail?
Maybe 1/2 litre with in an hour. I have pressure on the oil side-like you say it shouldn't make a difference... I'm testing the right cooler. The machine is in remote part of the Yukon so I doubt vandalism.... Serial number is 2KR04346. I was wondering if there is a frost plug or similar in the end of the engine where it could get through to TC and trans...
My mind is a bit fuzzy on the G model Cats but didn't they go to a radiator type cooler for the transmission oil on them?
No it's cylindrical-21" long and around 6" diameter.
Yep! Core should be a 7W0205 for new but it is available as reman or "Yellow Mark" under different part numbers. To be honest I never got too involved with a 3406 engine so hope someone else more familiar with them can chime in on any core plugs that could leak to let coolant into transmission. Below is a screen capture off SIS and the rear of block shows having a plug and seal #24 and #25 but I have no way of knowing if they are in the coolant passages or something else or if they are even in a place that could let coolant into the fly wheel housing. That same plug and seal is used at the front of the block but still not sure what is inside of it!
hi, Even if there is coolant leaks at back of block it would be contained with in the flywheel housing and show up in the engine oil I agree with ken that you need to check the cooler under operating temperature conditions Mark
I believe flywheel housings on all the conventional drive train wheel loaders I have worked on are wet and have a drain directly to the bottom of the transmission drop box. You can follow the piping from the torque converter housing to be sure.
Not having any experience with getting that deep into a 3406 I was not sure if that plug was in the water jacket and was located somewhere that it could get into the transmission oil. I would just be guessing that the flywheel and pump drive gears ran in transmission oil but then the pump gears might also be lubed by engine oil. One of the problems with trying to come up with ideas on a machine one never saw apart. Hope I didn't cause too much confusion!
hi ,to clarify. the flywheel side of the flywheel housing is a wet area of the transmission . the engine side of the flywheel housing is a wet area related to the engine. the rear crankshaft seal separates the two areas and this side would contain any coolant loss to the engine sump Mark
Just thinking on this cooler, is it one of those that has molded rubber sealing the ends around the tubes? I'm wondering if by some strange luck the pressure on the oil side would be holding the "leak" closed while it is running and then when oil pressure drops and there is still some water pressure in the cooling system it then can flow into the oil, kind of like a check valve deal. It might pay to make up some plates for the ends of the cooler core to put air pressure on the coolant side to see if that is what is happening. A few minutes with a couple scraps of steel should do the trick. I'd even start low, with say 10 psi pressure to see what happens. And if possible fill a tub with hot water to see if that makes a difference. A bit unrelated to this problem but I once had a problem finding an internal coolant leak in a 16V-71 could not find a drop of water coming from any of the normal places with pan off and 20 psi into the radiator. Left for the day and came back in the morning to find a big puddle of coolant on the floor of the shop. Followed drip up stream and it was then obvious it was a bad water pump seal. For some reason pressure in the cooling system would make the seal work but with no pressure it would leak.
Hey guys thanks for the help. I finally got the new cooler sent in here and fitted it-no more coolant in the trans so I guess it must have been a 'one way' leak. Anyway we started sluicing today and the transmission light and warning light come on. I changed the filter when I fitted the new cooler and cleaned the screen this evening but the lights are still on. Can anyone tell me if it is just pressure related when the lights come on or does it have other sensors-maybe residue of coolant in the system that it detects etc etc. Any help you can give me would be awesome...I don't have an operator manual here but am looking online for that and the shop manual...
is this the light symbol that came on
For a downloadable Adobe pdf Operator Manual try this link ............ you didn't mention the machine Seiral Number otherwise I could have told you what publication number to search for. An Operator Manual is about $45, a Parts Manual around $90. https://catpublications.com/Search/
Serial Number was in post #3 "Serial number is 2KR04346." This is what I find doing a search on 2KR: https://catpublications.com/Search/recall?savedSearchId=e1ac6f94-fa7d-e811-9106-005056a270f1
Mark-yes that's the light. I have an operators manual downloading now-thanks for the link.
That light "should" come on only if the transmission filter switch is activated. I believe that is a normally closed switch switch #164-7577. I could be wrong but if you unplug the switch light would normally come on and if you jumper the contacts in the harness it should go off. Hope I said that right! I see you have changed the filter at least once could be there is still some thing in there causing a problem. I put the "should" in quotes because we had a problem with the "filter plugged light" coming on in a 988H and after chasing ghosts for months found the real problem switch was a temperature switch on the transmission control valve never got a good explanation of why that was causing the plugged filter indicator to light up!
Ken, I think the OPs 980G is a slightly different animal and not quite so high-tech as a 988H. I would be checking the wiring of the plugged filter switch first, followed by a check of the switch to see if it’s opening and closing correctly. If that all checks out the next move would be to see if the bypass spool in the filter head is stuck/worn, or maybe if the springs have broken. You’re correct in that jumpering the wire harness for the switch should put the light out.
Yes it might be different but I checked and it uses the same by-pass valve switch. As I recall the switch is worked by a pin on the end over the by-pass valve that has a couple springs inside it. Easy to remove and test it's operation. Nice simple on/off switch either open or close contacts.
OK thanks.Changed the oil and filter this morning and the lights are staying off at the moment. There is another issue though... When you go from 1F and put your foot on the RH brake pedal-fairly hard-it shifts back into 1N. If you are gentle on the RH brake it stays in 1F as it should. Same when you are backing down the tailing hill in 1R if you put your your foot down too hard on the pedal it shifts back to 1N. The park brake light and the brake pressure light also flash simultaneously for a split second as it shifts into neutral. Like I said if you are gentle on that RH pedal it stays in gear and neither brake lights flash on. The foot brake also seem 'fiercer' than usual.... When using the LH brake it shifts back to 1N instead of just disengaging it while your foot is on the pedal. Is there any way the trans/brake issues could be related?
Going to owe you all a few beers by time this is sorted...
Based on the low brake system pressure and parking brake lights flashing when you press the pedal the first thing I would suggest to check would be the precharge pressure in both front and rear brake accumulators. In case you're not aware the brake pump on that loader is not capable of supplying the total oil flow required by the whell brakes (especially once the friction discs get a bit worn), so there are 2 accumulators that are charged up by the brake pump when the brakes are not being used, and which provide the additional oil flow necessary when either left or right pedal is pressed. Find attached below the explanation of the brake system operation. Note how if the parking brake is applied the transmission autmaitcally neutralizes ........... also note that the supply to the park brake valve comes from the main brake circuit - pretty much direct from the accumulators being honest. As an aside, make sure the cab floor under the brake pedals is kept spotlessly clean, a bit of mud/dirt under the back end of the pedals, meaning you're running with the brakes permanently (partially) applied, can land you in a world of hurt.
I forget if there is a spec for it but seem to recall that if you run the engine up till the accumulators are fully charged with oil and then shut off the engine and make applications of the brakes you should get something like six application before you loose brake pressure. If you listen you can hear the "clunk" when the accumulator piston hits the end of the accumulator. You can also hear the oil flowing through the system at each application with motor off. Okay I did a check on my notes from a 2KR03036 we had at the quarry. That one was showing almost the same problem as this one. As expected it was low accumulator pressures. They should have approx. 800 psi of nitrogen in them with no oil pressure ours showed 200 psi. After charging to 800 psi and running the engine till charge valve kicked out and then shut off engine and turned key back on I was able to get 6 applications of the brakes before pressure dropped and the low brake pressure light came on. My notes say minimum of 5 applications before low brake pressure light comes on. So It sounds like you need to get someone with the tooling and a bottle of nitrogen out there to recharge the accumulators. One suggestion would be to make sure you have a pair of new valves to put in the accumulator as with age they can tend to leak and not hold a charge. Would hate to have to get someone out there a second time! I was lucky as we had the tooling and nitrogen in stock so when I had to do it the second time down time was about zero. I'd be a little upset with my dealer, they don't have the valve or core on the shelf! But at least they say they can have in one day. I'd have two of item 2 and 3 in hand before doing the job.
Next time I'm in the Yukon I'll take you up one that! Now if you want to pay my airfare I could ask the boss from the quarry I retired from three years ago if I could borrow the accumulator kit for a few days I'd do the job for a couple beers and maybe some elk steaks!
Thanks for all the info once again-that all makes sense. Just heading down the creek now so will let you know. You shouldn't joke about coming up here-I have a couple of in-frame rebuilds to do as well as plenty of other jobs to catch up on....Anyone keen?
Forgot to say we are about a 35 minute flight from Dawson City so it's a little isolated. Caterpillar won't put any service mechanics on a plane unless it's twin engined with 2 pilots so it can start getting expensive. We haven't had to do that yet...
If that's the case I'm thinking you would be money ahead to get a kit to charge the accumulator yourself! Especially if you have more than one machine with the accumulators in them. We had the "Genuine Cat" kit at the quarry but I'm sure one could find one for much less money these days as it is basically just an adjustable pressure regulator similar to what you use on an oxygen tank for a torch and a couple hoses and an adapter to attach hose to the valve on the accumulator. I might try contacting whoever you get your welding and cutting gases from they may have a kit on the shelf or point you in the right direction.
The nitrogen kits can be assembled from off the shelf parts. I used to get the valves from a hydraulic fitting outfit in Seattle as well as the plastic hoses and the hand valves. I built a manifold from hydraulic fittings for doing suspension struts and got the regulator set from a welding supplies company. If you go that way get the highest reaching regulator you can get. My first one went to 500 PSI and that wasn't enough. You can do these without a regulator and just use the valve on the tank. But it only takes one mistake to pay for the cost of the regulator.
Yes our "Official" was actually one bought back in the early 988 days 87A1964 was one of the machines we used it on to give you an idea and latter on when we got some of the 769 and 773 haul truck in the company I scrounged up some extra shut off valves and some heavy duty pipe tees and such and made it so you could charge both suspension cylinders at the same time. Just as long as the lines and fittings used can handle say 2100 psi not too much to setting it up from parts, yes a regulator is best if only for safety. Have even had to use it on some stone crushers, ElJays, Nordberg and such as well as a couple hydraulic hammers! Also can be used to inflate tires if you don't have a compressor handy or buy into the nitrogen is better for tires thing! Now I did it probably start a thread on that one!