M936 not shifting out of first

[162tcat]

Well, that took an unexpected turn. The help from both sides of this purchase has been great. The forum was quick with replies other than the old "Read the TMs" and the sellers have been out in the cold trying to troubleshoot the problem. A problem that was voluntarily noted during my initial inspection.
I hardly think Allison transmission diagnosis and repair falls under safe operation of any MV and is likely outside of any basic soldier driving or commercial driver training. Assuming that people who are not collectors are dangers to the hobby is painting with a broad brush. I'm not sure how anything here is considered unsafe. I was not advised to operate the rear winch while dangling from the crane. I was presented with a transmission shifting issue. While you're quick to be critical you've offered zero technical advice. I'm here to assure you that while I may not have rebuilt any MT654CR Allisons in my day I have been employed as both a wrecker operator and a heavy equipment operator.

That's great that they have been out working on it. BUT, was it advertised with transmission issues??

Here is why I'm so jaded on this topic. I've witnessed many people get burned. I'll provide 3 great examples.

1st - Canadian guy buy a truck in WA that was on craigslist. The posting pic had the Govplanet logo blacked out. Too lazy to even take pics and just used theirs. Anyway, said purchaser drove 6 hours to purchase truck that was advertised as a solid truck that would have no problem making the trip back to Canada with a "government title" aka sf97. Guy pays cash for truck and leaves. He has a blowout after 10 min on the freeway, seller told him sorry, truck was sold as-is. He calls the 800 number on the govplanet sticker that was still on the truck. They give him Russell's number, the local Govplanet rep at the time. He puts him in contact with me. I told the guy I have a spare and met him in Tacoma near the mall and help him swap it out (for free). He tells me the whole story and I had to break it to him that the SF 97 wont get him across the border. He calls seller. Again, as-is where is, don't call me again. So, truck went to my house for almost 3 months while I helped him work out the title issue. In that time 3 other tires went flat. Looked up the listing on gov planet and they were shown flat in the pics too, no wonder the tire blew. End result is I loaded it on a low boy for him and he had it shipped to Canada. Cost him much time and money due to a shady seller. I charged nothing for any of my help, just felt bad and wanted to help out as he was a great guy.

2nd - A guy bought an M818 up near Forks, this may have been a craigslist deal but I don't recall. Paid cash for what was sold as a "turn key" truck. He knew nothing about military trucks but it looked cool and he was ready to own one! Jumped in with no info and headed home to Shelton. He was pulled over shortly because he didn't know that there is no brake lights if the 3 lever switch was not turned on but got off without any citation. Who knew! Oh wait, the TM's. He was following his chase car instead of them following him but well get to that. Later in the trip, he ran out of diesel even though the gauge said half. They got a hotel and paid a some local shop to get help get is going because apparently you can just dump some fuel in the tank and fire it back up. Who knew! Oh wait, the TM's. Now, the fun part. They were almost home when the brake pedal went to the floor!! He almost rear ended his girlfriends Newer Toyota Camery, pulled the ebrake but nothing much happened (out of adjustment!!) and put it in the ditch. At this point he started calling friends to help him get it out and trailer it home (he had no idea how much it weighed). He was given my number through a friend of a friend of a friend type of thing. The next morning, I met him where he wiped out near Harstine Island. I pulled it out, put it on the tow bar and dropped it off at his house. After he told me the story of all of the issues he had on the way home, I gave him a basic education on how to maintain and operate his truck over a few beers and told him about the site and where to get the TM's. Again, no charge. Just want to see someone enjoy the hobby responsibly and not kill me with their truck if I happen to be cruising the same streets in my Prius commuter!!

3rd - I'll keep this short and sweet because I'm tired of typing. A local guy bought a truck in CA sight unseen (stupid in my opinion) based on a video and the word of the seller. I believe he paid like 15K. The truck was a M931A1. Paid to have truck shipped here and while it did start and run, the oil looked like chocolate milk and it didn't quite run right. I met him a Lowes when I was picking up 3 pallets of roofing in my M923A2. He told me the story and I offered to take a look. I discovered the t-case was cracked too! Long story short, he went round and round with the seller, got a very small refund that only covered shipping and the truck still sits behind his barn rusting away.

So, yes, I'm concerned with the safety for myself, the operator and others on the road. I also don't want to see someone get sold something that's not in the condition they were told initially, especially when they took out a loan for something that was likely purchased for just over scrap value over 5 years ago. The seller may not have had bad intentions but being uninformed from lack of due diligence and using that as an excuse isn't much better in my opinion.

It's all good though, I'll be the bad guy here. Good luck with the sale/purchase and be safe out there.

 

[74M35A2]

 

[98G]

Lindsey97 in Wynnewood OK has a transmission new in the can.

He also has a pretty good truck he's parting out. The truck drove and shifted fine - lost the coolant into the oil.

 

[simp5782]

In my experience with Allisons when they go out, they go out. They don't attempt to shift or only have a forward gear. Its just nothing. Reverse has its own clutch pack and will usually work. That being said if its a pump pressure problem, putting it in low range will allow it to work. The pump doesn't have to work as hard to move the truck.

First steps should be. Verify fluid level is correct. Verify trans temps with an IR gun.

Check power divider is off with the in cab handle. Then crawl under and verify on the transfer case that its not engaged. It may be worn enough to engage but not fully disengage.

Verify modulator cable is not loose or broken. Or the wound spring isn't snapped.
Verify shifter cable is not loose or worn.
Verify transmission pressure

https://youtu.be/GEBD_v58vbk


Sent from my SM-G935P using Tapatalk

 

[74M35A2]

Several members here have had excellent luck with Allison dealers. One hour of tech time has resolved numerous issues such as this.

We should be the ones mad. You just registered here to get on and yell at us, get answers to solve your problem, then we’ll never hear from you again. You have no intentions of contributing anything to our knowledge base or member well being. We should consider a 3 day waiting period on new registrants to prevent this from occurring again going forward.

 

[74M35A2]

.

 

[Mrsbryner]

The guy never bought the truck, so there was no money exchanged and no there wasn't 4 hours for the answers below. The buyer has been to our house every day and has been on the phone with my husband and they were both trying to figure out the issues. No one knows if the transmission is messed up or not.

 

[Mrsbryner]

Thank you for the information. I will give this information to my husband.

 

[Mrsbryner]

That's great that they have been out working on it. BUT, was it advertised with transmission issues??

Here is why I'm so jaded on this topic. I've witnessed many people get burned. I'll provide 3 great examples.

1st - Canadian guy buy a truck in WA that was on craigslist. The posting pic had the Govplanet logo blacked out. Too lazy to even take pics and just used theirs. Anyway, said purchaser drove 6 hours to purchase truck that was advertised as a solid truck that would have no problem making the trip back to Canada with a "government title" aka sf97. Guy pays cash for truck and leaves. He has a blowout after 10 min on the freeway, seller told him sorry, truck was sold as-is. He calls the 800 number on the govplanet sticker that was still on the truck. They give him Russell's number, the local Govplanet rep at the time. He puts him in contact with me. I told the guy I have a spare and met him in Tacoma near the mall and help him swap it out (for free). He tells me the whole story and I had to break it to him that the SF 97 wont get him across the border. He calls seller. Again, as-is where is, don't call me again. So, truck went to my house for almost 3 months while I helped him work out the title issue. In that time 3 other tires went flat. Looked up the listing on gov planet and they were shown flat in the pics too, no wonder the tire blew. End result is I loaded it on a low boy for him and he had it shipped to Canada. Cost him much time and money due to a shady seller. I charged nothing for any of my help, just felt bad and wanted to help out as he was a great guy.

2nd - A guy bought an M818 up near Forks, this may have been a craigslist deal but I don't recall. Paid cash for what was sold as a "turn key" truck. He knew nothing about military trucks but it looked cool and he was ready to own one! Jumped in with no info and headed home to Shelton. He was pulled over shortly because he didn't know that there is no brake lights if the 3 lever switch was not turned on but got off without any citation. Who knew! Oh wait, the TM's. He was following his chase car instead of them following him but well get to that. Later in the trip, he ran out of diesel even though the gauge said half. They got a hotel and paid a some local shop to get help get is going because apparently you can just dump some fuel in the tank and fire it back up. Who knew! Oh wait, the TM's. Now, the fun part. They were almost home when the brake pedal went to the floor!! He almost rear ended his girlfriends Newer Toyota Camery, pulled the ebrake but nothing much happened (out of adjustment!!) and put it in the ditch. At this point he started calling friends to help him get it out and trailer it home (he had no idea how much it weighed). He was given my number through a friend of a friend of a friend type of thing. The next morning, I met him where he wiped out near Harstine Island. I pulled it out, put it on the tow bar and dropped it off at his house. After he told me the story of all of the issues he had on the way home, I gave him a basic education on how to maintain and operate his truck over a few beers and told him about the site and where to get the TM's. Again, no charge. Just want to see someone enjoy the hobby responsibly and not kill me with their truck if I happen to be cruising the same streets in my Prius commuter!!

3rd - I'll keep this short and sweet because I'm tired of typing. A local guy bought a truck in CA sight unseen (stupid in my opinion) based on a video and the word of the seller. I believe he paid like 15K. The truck was a M931A1. Paid to have truck shipped here and while it did start and run, the oil looked like chocolate milk and it didn't quite run right. I met him a Lowes when I was picking up 3 pallets of roofing in my M923A2. He told me the story and I offered to take a look. I discovered the t-case was cracked too! Long story short, he went round and round with the seller, got a very small refund that only covered shipping and the truck still sits behind his barn rusting away.

So, yes, I'm concerned with the safety for myself, the operator and others on the road. I also don't want to see someone get sold something that's not in the condition they were told initially, especially when they took out a loan for something that was likely purchased for just over scrap value over 5 years ago. The seller may not have had bad intentions but being uninformed from lack of due diligence and using that as an excuse isn't much better in my opinion.

It's all good though, I'll be the bad guy here. Good luck with the sale/purchase and be safe out there.

Trust me, we do not want anyone hurt. We did not post that it had transmission issues because we do not know if it has transmission issues. We are taking the truck tomorrow to have it hooked up to a scanner to find out. Like I said before, we are literally doing everything we can to fix the issue and if we cannot then we simply are not going to sell the truck and the buyer knows this.

 

[Mrsbryner]

Well the -10 doesn't offer troubleshooting it , it offers proper operating techniques for safety and to prevent damage. You don't take a driver that only drove a F-350 with a wheel lift and put him in a Kenworth with a rotator without training. The military likes specing thing out that are not normal on civy trucks , take the lockout to prevent shifting into reverse on the M939 siries trucks because of a known problem with them spliting transfer cases. Or the spring brake override you won't find on a civy truck .
For a mechanic to have a truck for 5 years without any manuals really raises red flags , like where did he get torque specs for repairs ect.

We purchased this truck from my husbands work, and no it did not have any manuals I believe. We barely used the truck in the 5 years we have had it. We haven't had any issues until hear recently, so therefore, no repairs have had to be made.

 

[74M35A2]

There is no scanner to connect, it is a mechanical transmission.

When my 1992 Ford Temp was stuck in first, with no other sign of transmission misbehavior, I removed the governor cover, pulled the governor assembly, and found that the spool valve in the center of the governor shaft had worn a burr on the shaft, and this was preventing it from sliding as the flyweights sprung out. I was able to fix it with a hand file in the street, and it was fine for all 223,000 miles when I sold it still running perfect. I would check that, and if not it, take it to or pay to have an experienced Allison tech stop out and do an assessment. Should only be 2 hours of labor time, say maybe $250 at most, guessing. I didn't know anything about auto transmissions then, and still don't, except that I don't like them.

If it won't shift out of first, it could be governor related, which is externally serviceable. Pull the governor cover, pull the governor, examine how each of its parts move internally and externally, and the O rings around and within it. Could be a ball of rust from sitting. Trans fluid pressure vs the governor flyweight force is what determines each shift point, each slightly compensated by modulator position which has limited authority. Something in the valve body could be stuck also. These things don't like to sit.

NOTE: We're still here and trying to help both sides, even though you came in swinging, and you will leave once this is behind you. We're not such bad people, it is just a little nicer to say hello at first meet rather than throw a brick through the front window when you pull up and get out.

 

[Mrsbryner]

There is no scanner to connect, it is a mechanical transmission.

When my 1992 Ford Temp was stuck in first, with no other sign of transmission misbehavior, I removed the governor cover, pulled the governor assembly, and found that the spool valve in the center of the governor shaft had worn a burr on the shaft, and this was preventing it from sliding as the flyweights sprung out. I was able to fix it with a hand file in the street, and it was fine for all 223,000 miles when I sold it still running perfect. I would check that, and if not it, take it to or pay to have an experienced Allison tech stop out and do an assessment. Should only be 2 hours of labor time, say maybe $250 at most, guessing. I didn't know anything about auto transmissions then, and still don't, except that I don't like them.

If it won't shift out of first, it could be governor related, which is externally serviceable. Pull the governor cover, pull the governor, examine how each of its parts move internally and externally, and the O rings around and within it. Could be a ball of rust from sitting. Trans fluid pressure vs the governor flyweight force is what determines each shift point, each slightly compensated by modulator position which has limited authority. Something in the valve body could be stuck also. These things don't like to sit.

NOTE: We're still here and trying to help both sides, even though you came in swinging, and you will leave once this is behind you. We're not such bad people, it is just a little nicer to say hello at first meet rather than throw a brick through the front window when you pull up and get out.

Thank you for the information. I will pass this along to my husband this evening. Yes your right I shouldn't have come out swinging like I did and I apologize, but it just came across all wrong with a couple of people saying what they said. No ones knows the entire conversation or what is going on between us and the buyer. So again I apologize for all that I have said. We just want to figure out what is wrong and get it fixed so the buyer has a great running vehicle. We are not out to make a quick buck or screw anyone over.

 

[74M35A2]

We hope everybody makes as much money as they can. Buyers set the price, not the sellers. Hope the trans gets fixed, and here is some humor to go with it. Laughing is better than fighting/yelling. None of us are here very long anyway:

 

[162tcat]

Thank you for the information. I will pass this along to my husband this evening. Yes your right I shouldn't have come out swinging like I did and I apologize, but it just came across all wrong with a couple of people saying what they said. No ones knows the entire conversation or what is going on between us and the buyer. So again I apologize for all that I have said. We just want to figure out what is wrong and get it fixed so the buyer has a great running vehicle. We are not out to make a quick buck or screw anyone over.

That's a better introduction. So lets get this fixed or at least diagnosed before money is spent at the mechanic.



Was the fluid checked? What was the result? Full and clean? Low? High? Burnt? Looks like oil? Looks like Dex? Make sure its being checked while running and check it at least twice in a row to get an accurate gauge.

Next, these are mechanical so the engine needs to hit the correct RPM to shift. What is the no load (neutral) max RPM on the engine? Is it hitting 2100+ under load? The modulator cable was suggested multiple times so we'll assume its good.

If all of that checks out, try putting the transfer case in neutral and see if the trans will run through the gears by manually shifting. While transfer case is in neutral and truck in gear, visually verify (carefully) transmission PTO isn't spinning.

Driving these is not like a car. You put your foot to the floor until the desired speed it achieved then back off to maintain speed. The shift points are controlled in the valve body and I've seen plenty that came from the military that weren't adjusted correctly. It can be adjusted by dropping the pan but its messy. Check on these items and report back. If all is good with the above info, its likely toast and swapping a take out if your best option.

Check the above items and most importantly, report back! This will help us help you and also potentially help anyone in the future who is looking diagnose a transmission problem.

 

[99nouns]

There is a saying where I come from "best friends happens after worst fights".

She apologized first so she is the better half.

Carry on troops...