Jumped of a cliff and bought a 1990-92? Cat 426 4x4 today. It has a problem with the electric drive lockout solenoid or wiring going to the reverser valve body I think. sometimes it moves, sometimes it doesn't. is there a common trouble spot on these you might know of. both the loader handle and shifter buttons have been torn apart and the solenoid has dents in it ( somebody beat it to un-stick it) or is this the sign of something else? When it moved it seemed to engage with gusto but then it kicked out again so it seems like a valve control problem and not a totally worn out reverser I hope. Thanks; John
Follow-up question. Does anyone know who made the shuttle(reverser) for the 426 cats? Thanks: John
Since this tread has been up 5 days and 235 hits. I'm guessing These things are pretty much bulletproof. Merry Christmas ; John
Whats your serial? Does it operate good in forward or is that affected as well? The neutralizer solenoid only gets power when the operator calls for neutralization so during normal operation it doesn't do anything.
If you disconnect the wire it should allow the solenoid to drop out and drive should engage. Have you checked for voltage at the solenoid? Could be a broken spring in the solenoid.
I haven't taken delivery yet so I don't have the ser. When checking the machine out It moved forward once. When it did engage it seemed to jump right in without slippage. never did get it to go backwards. So it seemed to me to be a engagement problem not a slippage problem. But if activating the solenoid causes dis-engagement it would make more sense for it to stick in the engaged mode. Maybe its leaking at the clutch plate servo?? how much is a rebuild? Thanks john
Finally got machine home. with wheels off the ground, they will drift slowly backwards when idling. The times it moved were one time when moving shuttle back and forth it went forward with power for no apparent reason, then it moved a couple times right after start up. start , went forward off truck, shifted to neutral and would not move again when shifted back to forward or rev. re-started 5 or 10 min later and backed up 50 feet or so shifted to neutral and would not move when shifted to fwd or rev.. It moved a couple more times after start up, but when shifter moved it stops and will not move until next start up. It has not run enough to heat oil. I think it is something "simple" like a needle in a haystack. It had low volt so I adj. up the fan belt,so that's not the problem. Ser no. 7bc01545 Thanks for any input. John
Based on your last reply, I wonder if your neutral solenoid is working intermittently (since it won't "go through" neutral).
today I took the top valve body off. everything was working not stuck or sticky. checked the connector to shifter and loader handle switch when pushed they energize the disengage sol. while valve body off I energized the sol. and it worked. the spool returned slow so I cleaned it. bottom line, it's not the prob. So this neutral solenoid you speak of DGODGR very interesting where is it located the only other wires I see go to neutral safety starter sw, single wire going to a sensor(?) buy the trans cooler line, and a two wire plug?? directly top rear of trans., and 4wd lockout. next step, drain and check for plugged screen or ?.. Thanks; John
We have a '92 CAT 446. The problem you have sounds like one we have had in the past. Ours was a simple fix...it was low on trans fluid! We have also had the 3rd gear solenoid go bad twice. Where it is located it catches all kinds of crap and just rots away.
I would say your next step would be to check your transmission oil pressure. I'm fairly sure the pump pressure tap is on the transmission case near the filter head. Leave the speed shifter in neutral and put the FNR in forward. You should have 175psi at low idle, 205psi at high idle. If you don't, the next step would be to check the suction screen and replace the filter.
I'm not sure if you have the same transmission as I do or not. The Cat repair manual (and the expeience) that I have is for "C" models but I think the basic trans and how it functions are the same. One major difference is the AWD portion is different and the hydraulic pump is trans driven on the "Cs". You should have a solenoid control valve on top of the transmission (remove the floor panel in front of the seat to access). This solenoid controls the oil that engages the clutch packs (froward or reverse). When the solenoid is in the neutral position the oil is diverted back to the sump. If you don't have the repair manual (many do not as they are very expensive) you should be able to see what the solenoid looks like from a parts book. In your post (#7) I am unclear about what is happening (symptoms). It sounds like it is not engaging in either direction (or at least it is doing it intermittently). If this is the case it could be an electrical porblem (but you are saying that the electrics are working ok), or that your transmission pump is not generating enough oil to properly engage the clutch packs, or that the clutch packs are worn. You have not said how many hours are on the transmission. When was the last time the trans filter was changed? Have you taken an oil sample lately (or is there a history in the Cat network-check with the dealer in the area it came from). Sometimes you will see a particular mineral count go up (and that specific mineral will be a clue to which component is suspect) in an oil sample. This info is exponentially more valuable if there is a history of samples. I will assume (and I hope you can confirm) that the "top valve body" you mentioned is the control solenoid. Is it electronicly activated? Can you get it to move by using the FNR lever (by the steering wheel-also known as the directional control lever). This will be easy if it is electronicly controlled but not if it's mechanical. If it is mechanical than you don't have a solenoid that controls the transmission. Even if it's not electric it is still controlled with a valve body and hydraulic pressure. If it is mechanical (I'm not going to be familiar with it) there is probably a mechanical adjustment. It is also possible that there may be enough wear that the mechanical linkage may be worn to the point of not working correctly. If linkage is not suspect the most efficient way to trouble shoot will be checking oil pressures at specific oil ports. Lastly, which 426 are we talking about? Since you said '90-92 I think it is a series II (426A series II) and I think they use mechanical linkage to manipulate the trans control valve body. Please confirm. My 416C has almost 12,000 hrs and has only had (1) transmission issue. A $2 snap ring broke on the all wheel drive shaft (inside the transmission). Unfortunately this requires removal and disassembly of the transmission to repair (on the "C" models). I hope that this helps.
Hi fellas and thanks for your interest in my problem: the oil level is slightly above the full mark cold not running. the valve body has a mechanical linkage to the f-n-r handle.The electric solenoid operates the loader and shifter clutch disengage, it was the original suspect but I saw it work while i had the valve body apart and other than that the only other solenoid is for the 4x4. I think you are onto something CMARK with the filter and especially pick-up screen, but I don't know where the screen is or how to access it. According to what I see on Richie specs I have a 1987 model year (by ser. no.) 426.They indicate it was replaced by 426II with tighter turning radius and bigger fuel tank and both 426/426II were replaced by the 426B, not sure of major differences. To clarify; If you start it and immediately put it in fwd or rev it will go about 30'. If you try to shift , it will not go again until you restart it after several minutes or overnight then if you restart it will do the same thing again, ether direction. Thanks; John
Just had another thought . could the pick-up tube for the pump have loosened or fallen off? Making it effectively low on oil like Gogitter mentioned ? Anybody know how I can access that?
The oil should be checked warm while in idle and neutral !! Do the check again. This might turn out to be a simple fix. On the side near the bottom it has an oval plate with a plug in the centre held on to the trans case with 2 bolts, this is the strainer.
Thanks for the info. Per Eriksson, I will do that before anything else. I will let you know.
Checked oil was o.k. so I went to the screen. Full of goo , cleaned it and cleaned out the housing with my finger, more goo, re-installed the screen added oil and drove it back and forth in driveway 1st thru 4th good. let it idle for about 5 to 10 min. went to park it and it would not move again? So I'm a little puzzled?. Took out screen. Some more goo, but didn't seem like enough to stop it. I drained the oil and plan on flushing the trans and cooler, t.c. if possible. Install new screen and filter, new cat oil. The goo was black oily clutch filings and some steel shavings also a chunk of gasket. With 8300 hours I don't think the metal was excessive but it must have never had the screen cleaned before with all the clutch goo. Can a plugged spin on stop the flow? Is there a t.c. drain? Thanks ; John
I would hope that the goo was retained in the trans (by filtration) by I would check the cooler, like you said. If you can't find a drain it should be fairly easy to remove a hose to drain the coller. With as much foreign objects as you are describing, I would be suspicious of the trans and feel more comfortable with a rebuild. Of course that's just my opinion, and it's your transmission. That goo came from somewhere (as did all the other stuff you found) and while I began reading your post I was thinking clutch fibers before you used that to describe the goo. At this point I would think that even if you get all the crap out your clutches are not going to work properly anyway because all the fibers are in the bottom of the your tranny. Again it goes back to the previous suggestion of oil pressure check. If you get all that crud out of your system and the trans still won't work right, then check the oil pressure. If it's within spec. than I would suspect the clutch paks.
Black goo is clutch material, if this plugs the spin on filter then it goes into bypass. when in bypass the oil continues into the trans and probably plugs up the orifices in the valve body and maybe the spools.
oh, some info, it is a late 1987 model and the trans SN in 000L7823 if it is the original.
Well I went to cat. No screen in stock but I got the filter and oil and new screen O- ring. Drained the T.C, and the trans ( both sides), took the oil cooler lines off, got just a couple drops, put it back together and it drives. Seems to be tight and responsive , time will tell, I don't think it will plug again because a lot off debris came out with the oil. Black flakes of carbon that my friend said looks like they came out of his coal bucket?? The machine came from pa., from a scrap yard next to an old coal mine no less. Making small talk I asked one of the guys at the yard if any coal was left, he said nah but they are taking out the fines. Now I am guessing most of the black goo is oil mixed with coal fines. I am pretty sure they did not use this mach. for loading so i have to wonder how the coal got into that trans? Anyway this forum was very helpful. Thanks again for all your input. John
Well some luck is good some isn't. Got 2.5 hours and lost fwd. rev is still strong so I am not suspecting the plugged screen. Ordered a trans rebuild with pump and t.c.. I started a new thread so if you have any advice on rebuilding one of these I'd appreciate it. Thanks; John