New to me M936 drive/transmission issues

[Mario]

I think my torque converter is locked up, but since I'm new to HD trucks, I need help to verify I'm on the correct path.
Recently purchased a truck that sat for years. It was a runner last time it was used.
When shifted into forward gear, the truck stalls.
Dropped valve body -- found 1 valve stuck. Addressed that. New filters and gasket along with 5 Gal of 10W, but no change.

Removed rear driveline.
Now I can shift into drive. The truck almost dies from strain, but once it warms up, it says running. Also stays running cold if I increase RPMs by about 100. The output shaft on TC spins, so I can conclude that my TC is not locked up, and my tranny is working.
Applying hand brake ends up stalling the engine.
Also, the transmission and TC PTOs operate without issues.

Am I correct in ASSuming that at idle the torque convertor should not be locked up, and applying the hand brake should not cause the engine to strain and die?

I've tried to 'exercise the torque convertor by applying and releasing the hand brake, hoping to loosen the stalled TQ, but so far, no luck.

If my train of thought is on the correct path, what would You try next?
I'm in New Mexico, and the only shop in town wants me to just replace the MT654CR at a cost of 4 grand -- a hard pill to swallow.

Thank you for any thoughts and/or ideas.

 

[simp5782]

I've got a few good takeouts or spend 2500 and put a 10spd in it.

Torque converter should unlock between 2 and 3rd gear when driving

This problem you are having is common

939 Allison Problems

Have been driving the recently aquired 925A2 quite a bit lately, and have been noticing a problem. When trans is shifted fron neutral to drive (1-5) the trans seems to "drop" in so hard that it stalls the engine of the truck. When I first got truck a few weeks ago there was no problem. Then...

www.steelsoldiers.com

 

[SpookyMulder]

If my train of thought is on the correct path, what would You try next?
I'm in New Mexico, and the only shop in town wants me to just replace the MT654CR at a cost of 4 grand -- a hard pill to swallow.

Thank you for any thoughts and/or ideas.

As mentioned in the thread that Wes linked, I would verify that all of your linkages are adjusted correctly. Actually there are several posts in that thread that may relate and are worth checking in to.

You mentioned your M936 stalls in drive. Does it stall in reverse as well?

 

[Mario]

As mentioned in the thread that Wes linked, I would verify that all of your linkages are adjusted correctly. Actually there are several posts in that thread that may relate and are worth checking in to.

You mentioned your M936 stalls in drive. Does it stall in reverse as well?

No, reverse works fine.
I read several posts about the air in fuel giving the same results (reduced power is enough to run the engine, but not drive it). I have installed a temporary setup to get rid of the air, but so far, no change in performance.

 

[Mario]

I've got a few good takeouts or spend 2500 and put a 10spd in it.

Torque converter should unlock between 2 and 3rd gear when driving

This problem you are having is common

939 Allison Problems

Have been driving the recently aquired 925A2 quite a bit lately, and have been noticing a problem. When trans is shifted fron neutral to drive (1-5) the trans seems to "drop" in so hard that it stalls the engine of the truck. When I first got truck a few weeks ago there was no problem. Then...

www.steelsoldiers.com

Thanks for the link to that post. I have already tried all of those things. So far, no resolution yet.

How much for a takeout shipped to 87144? I could pick it up from Fastenal or any shipping terminal in ABQ if that makes it less expensive to ship.

 

[simp5782]

Thanks for the link to that post. I have already tried all of those things. So far, no resolution yet.

How much for a takeout shipped to 87144? I could pick it up from Fastenal or any shipping terminal in ABQ if that makes it less expensive to ship.

Check to see if your rear power divider is engaged. This will cause the truck to die as well when you put it in gear.

 

[Mario]

Check to see if your rear power divider is engaged. This will cause the truck to die as well when you put it in gear.

I messed with it yesterday.
The power divider is the handle by the door on the wrecker, correct? I could move it, but to ensure I was getting full motion and no sticking, I disconnected the linkage and operated it manually.
That's the lever on the right, the rear side of the TC, correct?

Also, and this is only because I'm getting conflicting information.
In normal driving mode, with the PTO disengaged (OFF), the handle should be forward, correct?
This is per TM 9-2320-272-10, 2-24

 

[Mario]

Another question, to make sure I'm not screwing myself up.
Buddy and I temporarily removed the "INTERLOCK AIR CYLINDER". Wanted to make sure it wasn't sticking.
I'm waiting for 2nd person, so I can hold the plunger while he operates the TC shifter, and we can verify the High/N/Low engagement points (locations).

While I'm waiting on him, can I still T/S other components, shifting etc. or will the open airline prevent me from testing?
As I understand, the INTERLOCK AIR CYLINDER always has air, pressing the button on TC shifter lever shuts the air off, therefore allowing the plunger to ride up as TC's shifter selector rod rides back or forward.
But I'm also reading that the T/C shifter select button also has other functions (besides the electrical 5th gear tranny lockup), so I want to make sure I'm not screwing myself up. BTW, the air has no issues staying at 120psi with the engine idling, even with the INTERLOCK AIR CYLINDER (G) hose end opened, flopping/hissing in the wind.

 

[charlesmann]

Referring to reply #7 @Mario item 18 in the pic is the rear pto/power divider. Up and to the back of the cab is engaged/on and down, away from the cab is disengaged/off. I made the mistake a couple time of having the rear pto engaged, t-case in high a d went to 1-5 on the xmsn selector and it immediately stalled the engine.

 

[simp5782]

On a m62 and 816 it is forward for engagement
On a 936 it is forward as disengaged for future reference.

That shouldn't cause any issues. Those interlocks cause issues with shifting, most folks have to air down to shift H to N to L.

You can bypass that solenoid with a simple air line union. And leave it that way. This way it will only rely on lever pressure to stay in gear and it is easier to shift,