I have a D4E that just had the transmission cooler replaced. The transmission feels strong but there is an issue with a false neutral from time to time. I’ll explain. Sometimes shifts go as normal but from time to time when I select a gear whether in forward or reverse it doesn’t engage the gear. If you shift back to neutral then to the gear you want it engages and works all speeds from that point on. It only happens when switching directions and not when changing speeds if that makes sense. I’m curious to see if anyone had encountered this or has a lead on where to start.
Pull the seat up and clean the linkage out and check for wore out linkage . Bob
I took the panels off today and noticed little slop if any in the linkages. I reviewed the adjustment procedure and it stated at the end that all detents should be felt. I do feel all the gears and when operating half the time it goes right into gear and pulls. In the manual it mentions finding rubber particles in the screen of the transmission being an indicator of a seal failure. And unfortunately I did find some particles. Transmission was said to be rebuilt before I bought the machine but it has been years and it sat a while. Wonder if there could be remnants from before the rebuild. I’m sure if it gets any worse the pressures would have to be checked. I saw where some of the ports are but don’t know if I could buy a gauge and do it myself. Is that a common diy procedure? Can any seals be replaced or pressure leaks be fixed with the transmission in the machine? Of course if I get lead to there...
What is the trans/converter temp guage reading? Linkages are the place to start. Following that, gaskets on the pump suction line can create issues. So can tired o rings in the trans control valve. After that it starts to look like pressure loss in the transmission itself.
The torque converter temp is the only transmission related gauge I have on the dash. I believe. It usually runs in the first quarter to maybe half ways. Stays well into the green from what I’ve seen.
Did you remove & inspect the suction screens plus the condition of all the clamps, gaskets, o-rings, etc, in the powertrain oil lines suction side as far as the pump when you had the system apart for the cooler problem.? It’s not unusual for a joint or clamp to leak when things got hot if something is not 100% tight or a joint is old & cracked. Also does your transmission control linkage have any grease zerks on the bell cranks.?
I did not notice any grease zerks on the transmission linkage. I will check again. I had the piping from the transmission to the cooler resealed in 3 out 4 fittings. And loosened and retightened a rubber hose joint. Don’t know if that’s the suction side or not. Replaced the seals for the oil filter canister. New gasket on the suction screen on the bottom. I assume that’s the magnetic screen. Might not be... I didn’t see any other suction screen. manual is vague at time it seems. I did use T02 when I changed. Manual called for it but it sounds like most use T04 now. Reading slightly high on the dipstick when warm and running. Can the O rings in the trans control valve be checked easily or is that a tough job?
How crucial is the transmission linkage adjustment? It seems to catch the gears fine but if it would be worth my time to check adjustment I would. Seems like things don’t move much under there to select between forward and reverse. 1-3 seems to go click right through.
Not the same machine but we had the exact thing happen in an old 988A wheel loader. It had a safety valve in the transmission if you started it in gear the transmission wouldn't go into gear. You had to shift into neutral to get in gear. So it acted like yours sometimes it went in gear sometimes not. Back to neutral and it worked fine. Had a Cat mechanic check the pressures all were ok. They did drop as it went in gear which he said was normal. So I figured that drop maybe activating the safety valve putting in to neutral. The valve was spring loaded. When hydraulic pressure pushed the valve it could go into gear. So with that dip in pressure it would release and go into neutral. So I removed the valve body and took a wild guess at a weaker spring. I got lucky no more going into neutral and it still wouldn't move if started in gear. Now I don't know if your dozer transmission has that valve but it sure acts like mine did.
I’ve never tried to start in gear. Never thought of it really.
I would suggest to get a pressure gauge hooked up to the P2 (Direction) clutch test point. Observe the reading on the gauge when the transmission is failing to shift into gear. Even better get two gauges and have one on the P1 (Speed) clutch year point as well. Setting the control linkages starting from scratch is not difficult, although it’s a bit tedious if done right because there are lots of steps and you can’t skip any of them. It certainly wouldn’t hurt to do it. Do you have the procedure.?
Yeah I believe I do have the adjustment procedure. What I don’t have are the proper gauges.... what exactly would I have to buy to do the pressures? Would I need two gauges to measure in the two spots at once?
You would need at least one gauge capable of measuring up to 500psi, or two if you decide to hook up to both P1 & P2. TBH one on P2 would probably be enough to see what’s going on. I’ll find the adjustment procedure and post it up. However to make sure it's the correct one will require the tractor Serial Niumber.
As you noted, there is very little movement on the direction linkage, and it can give you the fits if not moving correctly. Usually though, it tends to want to make the machine move in the wrong direction to that selected. One of mine recently kept loosing drive when turning right and turned out to be the steering linkage occasionally catching the little vertical forward/ reverse linkage just before it goes into the trans.
Serial # 69X 0721
Here you go. The pressure testing is in the same document. The linkage adjustments are right at the end.
Definately go over the linkages. There can be wear on pivot arms,pins,rods...everything.Sometimes wear doesn't show until you separate the various linkage components. A few millimetres of wear at several points makes a big difference. If nothing else is achieved,you have a starting point & can cross it off the list...
Check pressure before adjusting anything. See what you're up against, first.
I've seen plenty of old Cat dozers where the transmission linkages get slapped hard all day long. With all the covers off, maybe you should slap the lever side to side and watch what happens at all the pivot points. The detents in the valve will handle a whole lot of slop in the transmission linkages. Checking pressures is the next step. You will see pressures drop between shifts because the valves modulate the shifting to take out some of the shock of changing directions. It sounds like you might have a worn transmission pump that may be a low on flow or some worn valves that take a few extra seconds to fill a clutch pack. At this point, you can't troubleshoot anything without a gauge or two to see what is happening with the pressures. I always used 600 PSI gauges for testing transmissions. Good Luck
I got to test the pressure today. P2 showed right at 250psi. If my gauge was accurate. It ran a little lower cold. 0psi in neutral. Would jump to 250 PSI during shifts, also would spurt a small amount of fluid when you went back to neutral. I assume that’s normal. Made no difference in pressures in either direction or speed. It didn’t seem to have any problems shifting today until it got good and warm then it started missing shifts, but still wasn’t as bad. Showed 0 psi when it didn’t shift. The only thing I have changed was took one part of a linkage apart to inspect it but it seemed tight. About it tho, it seems someone might have substituted a Allen head bolt with some shims to make it work? It seems good and tight but it’s on the direction side of the shifter and may be a problem if it isnt the factory part. I can post a pic of it later.
Here’s a picture of the linkage that’s in question. I wouldn’t think the Allen bolt holding it together would be appropriate. Haven’t found it in the parts manual yet. If that isn’t a factory connection then it would be worth trying what it calls for since there’s not much movement in the shifter from forward to reverse.
It's not what should be there, that's for sure. Take a look at the other end of that same rod. Both ends ought to be like the illustration below. Part Number is 3K-4290. With that "modification" it's quite likely that the transmission control linkage is incorrectly adjusted.
I'll bet The end on that rod is the right one but that bolt set up is not. Check the bell crank that rod is hooked to for free movement and how loose it may be. Replace that bolt and check the adjustment . Bob
I think that what is there is perfectly fine even if not factory. As long as it moves freely and the bolt stays perpendicular to the line of movement, it is not the cause of your problem.
Yeah if it’s not a factory set up it’s a fairly good looking fix. It has hardly any slop and it’s a moving joint the bolt rides in. Bolt fits right. Still might have to replace it. Here’s a picture of the other end of the rod.
One thing noticed while moving it around earlier was the decelerator pedal limiter was bent and missing the bolt stop. When I would idle down for shifts with the pedal, the rpm went down farther than the pedal would normally allow. I finally noticed the potential connection between the shifting and low rpm and it seemed repeatable. I could lower the rpm and make it not shift and raise it slightly and it would make the shift. Possible the low idle wouldn’t allow the transmission to shift? Once I straightened the limiter it will not idle quite as low when the pedal is used.
I think it is logical. Pump flow would drop with engine speed. Pressure on the safety valve would drop and and the valve would trip and then the transmission wouldn't shift into gear. It would be the same scenario of trying to start the engine with the transmission in gear. I hope your solution works.
I think you have it with the deceleration. I have seen a few over the years that we had to bump up the decelerator stop bolt to raise the rpm due to the pump getting weak. Yours was probably just dropping too low and the safety valve was kicking it to neutral.
If you look carefully you can see that long bolt shortens the throw on that rod . That bolt needs to be replace and the linkage adjusted. that set up should go into gear at a idle ,set the throttle at idle and try it. Bob
This is what I said in post #9. Raise the decelerator idle and try it.