T-Case not wanting to shift

[charlesmann]

Took my M936A2 out for a stroll and to finally use it for what i bought it. After several lite lifting jobs and repositionings, i went move in to position for my last lift job of the day. I disengaged the rear pto and went to put the case in high range, it wouldnt go, tried low, still no joy. I tried putting down and pressure while selecting 1-5 on the xmsn, still no joy. It took 4 attempts before the case went in to high range.
Any thoughts, places to inspect? Yes i had air (120psi) and i could hear the solenoid when i pushed button on the case shift lever.

Also, i have never had an issue with my xmsn indication but have also never used it to the extent i did yesterday, but the gage was showing pegging out on xmsn temp. Could it be a false indication as my eng temp gives most of the time?
when i get back to my tck in an hr, i will see when the temp reads while in building air. I will also hit it with my temp gun. Any specific location to check its temp?
My pmcs showed ample oil at both cold and operating temp.

 

[Mullaney]

Took my M936A2 out for a stroll and to finally use it for what i bought it. After several lite lifting jobs and repositionings, i went move in to position for my last lift job of the day. I disengaged the rear pto and went to put the case in high range, it wouldnt go, tried low, still no joy. I tried putting down and pressure while selecting 1-5 on the xmsn, still no joy. It took 4 attempts before the case went in to high range.
Any thoughts, places to inspect? Yes i had air (120psi) and i could hear the solenoid when i pushed button on the case shift lever.

Also, i have never had an issue with my xmsn indication but have also never used it to the extent i did yesterday, but the gage was showing pegging out on xmsn temp. Could it be a false indication as my eng temp gives most of the time?
when i get back to my tck in an hr, i will see when the temp reads while in building air. I will also hit it with my temp gun. Any specific location to check its temp?
My pmcs showed ample oil at both cold and operating temp.

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Well, I assume that you got your TC back into gear...
I have had that sort of problems with mine and it was loose linkage.
Lots of WD40 has helped make the PTO cable slide more smoothly too.

 

[charlesmann]

I did get it moved yesterday and it did it to me 1 time today.
the xmsn temp though, think is an indicating issue. I know it wasnt 240 degree outside this morning at 0945, and when i got to the job site, fired it up to let the air build and the temp gage airborne shuffled all the way to 240.

Once i get the trunk cut off from the root ball and most of the main limbs in the 14”+ size, ill bring it hm and see if i can figure out where the temp signal comes from and see if there is a napa special gage that’ll work and possibly provide a more accurate reading.

Havent figured out how to edit my gopro for vids, but here are a few pics of it doing specifically what i bought it for.

 

[Mullaney]

I did get it moved yesterday and it did it to me 1 time today.
the xmsn temp though, think is an indicating issue. I know it wasnt 240 degree outside this morning at 0945, and when i got to the job site, fired it up to let the air build and the temp gage airborne shuffled all the way to 240.

Once i get the trunk cut off from the root ball and most of the main limbs in the 14”+ size, ill bring it hm and see if i can figure out where the temp signal comes from and see if there is a napa special gage that’ll work and possibly provide a more accurate reading.

Havent figured out how to edit my gopro for vids, but here are a few pics of it doing specifically what i bought it for.

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Seems like a reasonable plan. Casually looking this afternoon, I didn't see a transmission cooler. Seems like there would be something to cool it. Heck, even a simple pickup truck has a cooler out front...

Guessing that you do remember that the TM's call for about 1500 / 1800 RPM or engine speed to avoid overheating the transmission?

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Nice pictures and it looks to me that that job is perfect for that truck!
I like pictures better than videos anyhow

 

[Crf450x]

@Mullaney The cooler is on the passenger side of the engine. Follow the bottom radiator hose and you'll see it.

Try shifting the transfer case with no air pressure. If it shifts good, the problem is related to the interlock. Mine was hard to shift until I took all the pins out and cleaned/greased them.

For the trans temp, the sender is in a cooler line on top of the trans. Should be very easy to figure out the issue. I'd recommend fixing the factory gauge....just because that's the "right way" in my opinion. Whatever you do, that should be priority 1. Don't want to burn the transmission up.

 

[charlesmann]

@Mullaney The cooler is on the passenger side of the engine. Follow the bottom radiator hose and you'll see it.

Try shifting the transfer case with no air pressure. If it shifts good, the problem is related to the interlock. Mine was hard to shift until I took all the pins out and cleaned/greased them.

For the trans temp, the sender is in a cooler line on top of the trans. Should be very easy to figure out the issue. I'd recommend fixing the factory gauge....just because that's the "right way" in my opinion. Whatever you do, that should be priority 1. Don't want to burn the transmission up.

You are correct, i dont want to burn the xmsn up, but i wouldnt think that within 2-3 sec, the temp would go from 90 to 240.
Fixing the factory gauge? You mean possibly replacing the sending unit, or replacing another 1 of those unreliable gauges? I dang sure dont want to butn up an eng either, but iv replaced the factory oul psi and temp gauges with mechanical.

I shot the fittings at the xmsn and the liquid to liquid cooler with my temp gun and all are reading between 185 to 206 accordung the gun, which is what is leading to an indication issue, not an actual issue.

I’ll try shifting with no air and see what i get. I do have to release the parking brake or maybe its just coencedence that it worked the past couple times. Usually, i can just bump the xmsn into gear and back out and t case falls rite in.

 

[charlesmann]

Today, i show up to the logging site, forgot to check t case shifting w/o air, but the xmsn gauge read normal till i went to pull the last of the log out of the hole and as soon as i got the chain tight, the gauge went from 180, rite to 240 and didnt pass go or collect $200. After getting the log trunk moved, and shut it down long enough to set my rear riggers and got my trailer lined up, i fired it back up and the temp was back to 180.

I didnt know the front end of these truck could be lifted off the ground while pulling a load, but mine did while in low range.

The estimated weight of the trunk was 13,000, plus part of the tree was still attached to the root ball (didnt know till i got it out) and was sunk in the ground about 18”.

 

[Mullaney]

Today, i show up to the logging site, forgot to check t case shifting w/o air, but the xmsn gauge read normal till i went to pull the last of the log out of the hole and as soon as i got the chain tight, the gauge went from 180, rite to 240 and didnt pass go or collect $200. After getting the log trunk moved, and shut it down long enough to set my rear riggers and got my trailer lined up, i fired it back up and the temp was back to 180.

I didnt know the front end of these truck could be lifted off the ground while pulling a load, but mine did while in low range.

The estimated weight of the trunk was 13,000, plus part of the tree was still attached to the root ball (didnt know till i got it out) and was sunk in the ground about 18”.

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That is some serious tree work there!

It has been a while since I saw it last, but I saw a wrecker build with counterweights. They were in a pocket on the front bumper hanging off the bumper extensions. Apparently a light front end with a load was what that was all about. Saw another setup with a large work box out in front of the winch. That update was to move weight to the front and to get straps, chains and other heavy stuff out from the toolboxes behind the cab.

Somehow or other it sure seems like there is a sending unit or ground problem - based only on the sudden changes.

 

[charlesmann]

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That is some serious tree work there!

It has been a while since I saw it last, but I saw a wrecker build with counterweights. They were in a pocket on the front bumper hanging off the bumper extensions. Apparently a light front end with a load was what that was all about. Saw another setup with a large work box out in front of the winch. That update was to move weight to the front and to get straps, chains and other heavy stuff out from the toolboxes behind the cab.

Somehow or other it sure seems like there is a sending unit or ground problem - based only on the sudden changes.

My unit does have counter weights on the bumper extensions, but evidently, not enough. It was NOT my intension to bring the front wheels off the ground, but it happened and rode it out till they contacted the ground again.

I too think its an indicating issue, either the gauge or the sending unit, due to erratic changes in readings, but will be bringing the tck hm tomorrow after loading of the bigger limbs and cleaning up the owners pasture enough for her to be able shred/mow her pasture. I was taught to leave an area/equip in better condition that was found, even though she said i didnt have to clean up, just pile what i didnt want into a pile for burning. But there is still 3-4 cords of useable wood, so ill go back on my next rotation hm from work, and ill order a new gauge and sending unit and hope that actually is the cause.

Im not sure if there is an internal pump or not (dont know much about automatics) but hopefully that isnt the culprit. I do have a xmsn out of my salvage/control exchange 936 that supposedly got burned up when the t case lever supposedly engage in high rage, from neutral, during towing from auction site to the storage site. I guess it would be wise to pull it and take it to the allison dealer/repair facility a few miles from the house, and have them quote a price on rebuilding it.

 

[Mullaney]

My unit does have counter weights on the bumper extensions, but evidently, not enough. It was NOT my intension to bring the front wheels off the ground, but it happened and rode it out till they contacted the ground again.

I too think its an indicating issue, either the gauge or the sending unit, due to erratic changes in readings, but will be bringing the tck hm tomorrow after loading of the bigger limbs and cleaning up the owners pasture enough for her to be able shred/mow her pasture. I was taught to leave an area/equip in better condition that was found, even though she said i didnt have to clean up, just pile what i didnt want into a pile for burning. But there is still 3-4 cords of useable wood, so ill go back on my next rotation hm from work, and ill order a new gauge and sending unit and hope that actually is the cause.

Im not sure if there is an internal pump or not (dont know much about automatics) but hopefully that isnt the culprit. I do have a xmsn out of my salvage/control exchange 936 that supposedly got burned up when the t case lever supposedly engage in high rage, from neutral, during towing from auction site to the storage site. I guess it would be wise to pull it and take it to the allison dealer/repair facility a few miles from the house, and have them quote a price on rebuilding it.

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There is nothing quite like having spare parts. I can only assume that the 936 uses a different transmission than the S&S trucks. Just based on how they operate with push buttons (like a 64 Chrysler) compared to the floor mounted shifter. I did a little digging and found a rebuilt and dyno tested Allison MD3070PT for $9975 with a year parts warranty. Can't remember if there was a core charge or not. Seems like the place was in Louisiana...

I think your mindset is just like a lot of us who have been around the block a time or two. The old treat others like you would want to be treated sums it all up pretty well. You can't buy the goodwill of a job done right. Spending that time cleaning up will make the next person hear about it if you didn't. Best part is that if she knows anybody that needs the services you've recently completed - you have somebody in your corner.

If you figure out some sort of magic on the transmission, I sure would like to know. Mine are functional today, but you never know.

 

[charlesmann]

I think the xmsns are the same across the 939 A2 series, maybe even the A1s. No push buttons on mine, except for the ctis, which has been disabled. I have the normal shift tower like in a 923A2.

 

[charlesmann]

I remembered this time to check if the t case will shift w/o air. Yes, it went into high, back to neutral, into low a d then back to neutral.

 

[Crf450x]

I remembered this time to check if the t case will shift w/o air. Yes, it went into high, back to neutral, into low a d then back to neutral.

Since you can hear the solenoid clicking, the electrical side is ok. If I remember correctly, the solenoid is on the driver side frame rail and supplies air to the actuator on the transfer case. You'll need someone to help but you can crack the air line going to that actuator and if pressure releases when the button is pressed, the actuator is the problem. Super easy to take it apart. It's probably just stuck and needs to be cleaned up. I'd replace the o rings while it's apart. Or, if you want, you can replace the whole thing.