D6H transmission overheating

[Pralhad Birdi]

That sounds about right for shims.

Not a tad bit excessive?

 

[Pralhad Birdi]

D 5h has 1 thick 1 medium and 2 thin shims.

Better than 8! I think haha

 

[Pralhad Birdi]

I’ll be opening up the priority valve tomorrow. If the priority valve pressure is set incorrectly, could that cause dragging brakes?

 

[Nige]

’ll reduce them to what you’re saying and then measure the pressures again once I’ve put everything back.

Bear this in mind. To set the Iniitial Pressure (with the control valve load piston plug removed) on P1 the specification is only 77+/-5 psi at Low Idle with everything warmed up to normal operating temperature.

If the spec target is only 77psi and if according to the chart in the T&A adding/removing one thick shim will change the pressure by approximately 14.2 psi then two thick shims IMHO are going to change the pressure one heck of a lot.....!!!

 

[Nige]

I’ll be opening up the priority valve tomorrow. If the priority valve pressure is set incorrectly, could that cause dragging brakes?

Just take a look inside it first and, like the transmission control valve, report how many shims it has in it. According to the Parts Manual the starting point should be 1 thick, 1 medium, and 6 thin shims.

Check the springs against Page 6 of the Specification document while you're in there, just to make sure they are the correct ones and have not been damaged..

 

[Nige]

You may have got the idea already but just to emphasise the point, you really need to check everything in the powertrain oil circuit looking for anything that out of whack. Missing parts, parts assembled in the wrong order, wrong/swapped springs in any of the control valves, etc, etc. That includes the inlet and outlet relief valves for the torque converter which I don’t believe we have mentioned up to this point.

 

[Pralhad Birdi]

Just take a look inside it first and, like the transmission control valve, report how many shims it has in it. According to the Parts Manual the starting point should be 1 thick, 1 medium, and 6 thin shims.

Check the springs against Page 6 of the Specification document while you're in there, just to make sure they are the correct ones and have not been damaged..

I’ll be doing this today, and I’ll revert back soon on the number of shims.

 

[Pralhad Birdi]

You may have got the idea already but just to emphasise the point, you really need to check everything in the powertrain oil circuit looking for anything that out of whack. Missing parts, parts assembled in the wrong order, wrong/swapped springs in any of the control valves, etc, etc. That includes the inlet and outlet relief valves for the torque converter which I don’t believe we have mentioned up to this point.

Yes I saw the torque converter valves in the specifications doc you sent, and after I’m done with the priority valve, those are the next step.
Oil cooler and control valve are going back onto the machine today, and steering valve and torque converter valves hopefully coming off.

 

[JAJ]

Are you pulling all these valves off and adjusting the shims without already knowing the pressure in the circuit they are regulating?
A pressure test of all the circuits would point you to exactly where you need to pull things apart wouldn’t it?
I’m sure you have reasons for doing what your doing I’m just trying to understand how your getting there.

 

[Nige]

Are you pulling all these valves off and adjusting the shims without already knowing the pressure in the circuit they are regulating?

No. Based on the fact that so many people have had hands on this machine recently he’s inspecting them all to make sure they are a) assembled correctly and haven’t had spools reversed or springs swapped, etc and b) counting the number of shims in each one to compare with what’s listed in the parts manual which is the starting point for pressure testing.

In the transmission control valve he found 2 additional thick shims over and above what should be in there to start pressure testing. That would increase P1 Initial Pressure by approximately 28psi and P1 full pressure by over 100psi which could potentially be dangerous. Those two shims in particular can always be reinstalled should test results indicate the need.

I think I commented earlier that my particular preference for setting pressures is to start low and work up to specification, just to err on the side of caution.

 

[Pralhad Birdi]

Are you pulling all these valves off and adjusting the shims without already knowing the pressure in the circuit they are regulating?
A pressure test of all the circuits would point you to exactly where you need to pull things apart wouldn’t it?
I’m sure you have reasons for doing what your doing I’m just trying to understand how your getting there.

Yep exactly what Nige said above

 

[JAJ]

Yeah ok that is what I was expecting the reasoning to be, that is fair enough. The assembled incorrectly/missing parts theory is a very like cause of the problems.
I would have gone about it by testing the pressures first to get a baseline and if things were way out of spec then adjusted accordingly or investigated area effected. Nige's method is probably a lot better then my method, just takes more time and may have to go back again to re-adjust them, but his is definitely safer for sure. It would absolutely have been what should have happened for the initial start up after the rebuild... but if you had done the rebuild you would probably have found all the extra shims too. I hope the damage hasn't been done already from the high pressures.

Reading how other people go about troubleshooting is awesome, seeing different and better ways of doing this stuff is what is so great about the forum. So keep up the great work and I am sure you will find the cause, very interested in the outcome!!

The fact it was driving for a bit and then stopping is very interesting

 

[Nige]

The fact it was driving for a bit and then stopping is very interesting

I may have read it wrong but I was under the impression that the reason it was stopping/being stopped was that the transmission (read powertrain) oil was overheating.

For all I know the problem could be in the converter, but you have to start somewhere.

 

[Pralhad Birdi]

Just take a look inside it first and, like the transmission control valve, report how many shims it has in it. According to the Parts Manual the starting point should be 1 thick, 1 medium, and 6 thin shims.

Check the springs against Page 6 of the Specification document while you're in there, just to make sure they are the correct ones and have not been damaged..

So the priority valve, apart from a fair bit of dirt, has 2 thick, 3 medium and 1 thin shim.
The free length of the spring is 44.9mm as opposed to 45.7 spec.
So I’ve removed one medium and one thin shim.
Re-installing now.

 

[Pralhad Birdi]

Yeah ok that is what I was expecting the reasoning to be, that is fair enough. The assembled incorrectly/missing parts theory is a very like cause of the problems.
I would have gone about it by testing the pressures first to get a baseline and if things were way out of spec then adjusted accordingly or investigated area effected. Nige's method is probably a lot better then my method, just takes more time and may have to go back again to re-adjust them, but his is definitely safer for sure. It would absolutely have been what should have happened for the initial start up after the rebuild... but if you had done the rebuild you would probably have found all the extra shims too. I hope the damage hasn't been done already from the high pressures.

Reading how other people go about troubleshooting is awesome, seeing different and better ways of doing this stuff is what is so great about the forum. So keep up the great work and I am sure you will find the cause, very interested in the outcome!!

The fact it was driving for a bit and then stopping is very interesting

Yeah just based off of the fact that I don’t know what was done to it initially, I’d rather not run it for too long and risk damaging something else.
So the stopping was due to the transmission overheating. Well I hope it was, and not something to do with the converter like Nige said.
Cheers man!

 

[Nige]

So the priority valve, apart from a fair bit of dirt, has 2 thick, 3 medium and 1 thin shim.
The free length of the spring is 44.9mm as opposed to 45.7 spec.
So I’ve removed one medium and one thin shim.
Re-installing now.

You should be worried about the dirt. It’s in that valve so by inference it’s going to be everywhere. Not good - extensive cleaning may be required.

Spring sounds like it is very tired. The priority calve probably works harder than any of the others. Can you check with the dealer just in case they have one available.?

 

[Pralhad Birdi]

You should be worried about the dirt. It’s in that valve so by inference it’s going to be everywhere. Not good - extensive cleaning may be required.

Spring sounds like it is very tired. The priority calve probably works harder than any of the others. Can you check with the dealer just in case they have one available.?

I’ve sent an enquiry, waiting to hear back from them.

 

[Nige]

So the priority valve, apart from a fair bit of dirt, has 2 thick, 3 medium and 1 thin shim.

That adds up to 6.15mm of shims. 2 x 1.6, 3 x 0.9, 1 x 0.25.

The Parts Manual starting point is 1 thick, 1 medium, and 6 thin which in total adds up to 4mm. I would suggest to make whatever combination that you put back add up to 4mm.

 

[JAJ]

I may have read it wrong but I was under the impression that the reason it was stopping/being stopped was that the transmission (read powertrain) oil was overheating.

For all I know the problem could be in the converter, but you have to start somewhere.

Yes, I was thinking it was stopping driving and cooking the oil in the process while only going 150m. You had it correct though according to the OP, so my misunderstanding.

I am very interested to hear what happens when it’s all back together after checking and adjustments.
With dirt found in one valve, the valves on the torque convert will be interesting to see next.

 

[Pralhad Birdi]

That adds up to 6.15mm of shims. 2 x 1.6, 3 x 0.9, 1 x 0.25.

The Parts Manual starting point is 1 thick, 1 medium, and 6 thin which in total adds up to 4mm. I would suggest to make whatever combination that you put back add up to 4mm.

Okay will do.
I’ve got the torque converter outlet valve out as well, how many shims should that have as per spec?
Thanks