M925A2 reverse issue

[CaptainBillUSMC]

Hello! Been a few months since I've been on here. Was real sick with pneumonia and the shingles for a few months. Fortunately, the truck I am interested in is still available. The guy doesn't need to sell, but he is willing to sell it. He's an experienced buyer/seller/owner of these trucks. So, I am back in the saddle and ready to go!

He was driving it yesterday in prep for me to make the 2.5hr trip to see the truck, drive, it and ask lots of questions. It started and idled nicely. Drove forward just fine. But, it did NOT go in reverse very smoothly. He also noted a winding sound either coming from the Xfer case or the Xmission. When he stopped, he checked the fluid. Looked and smelled as it should, but he noted it was a little over-filled. Went underneath the truck and noted some play in the shifter cable. No other issues noted . The truck has had Xfer case maintenance fairly recently and had a take out one put in.

I searched this forum and was unable to find exactly these issues. Those who had reverse issues couldn't get the truck in reverse at all. And, no one noted a winding sound either. Does anyone have any insight in this issue? Are they related? I don't want to buy a truck that's going to leave me stranded on the way home, nor would the wife like it if I parked it and it needed major maintenance. We are both from the aviation industry so neither of us are delusional about maintenance, esp on older stuff. Her plane just broke the other day, so she gets it. But, at the same time, she doesn't want to see me get a truck knowing that there is an issue looming. If this is an easy fix, I'm ready to pull the trigger!

Thanks in advance!

 

[NDT]

If the transfer case drives in forward, it would be highly unusual for it to not drive in reverse.

 

[CaptainBillUSMC]

If the transfer case drives in forward, it would be highly unusual for it to not drive in reverse.

It drives in reverse, just doesn't shift smoothly. Could that be related to the play in the shifting cable? Thanks for the reply.

 

[NDT]

If the shifter is not placing the valve body control into the full detent position, this could cause anomalies. This “slipping” upon engagement could also be related to pistons in the valve body and servos being a bit stiff from lack of use. He should take it out and drive the crap out of it and see if that gets everything loosened up.

 

[Jbulach]

It drives in reverse, just doesn't shift smoothly. Could that be related to the play in the shifting cable? Thanks for the reply.

Theres no chance the transfer-case was in low range is there? I believe there was an MWO that installed a low range reverse lockout on “most” of these trucks to prevent shifting into reverse while in low range. If the seller is very experienced with these trucks I would be a little leery if this issue can’t quickly be resolved, especially with the whining noise.

 

[Jbulach]

Do you have any more info/description on “play in the shifter cable”, or “not going into reverse smoothly”? IE, did you have to work the shifter back and forth, play with the throttle, just took a while to engage? Was the play on the transmission, or shifter end of the cable?

 

[CaptainBillUSMC]

Theres no chance the transfer-case was in low range is there? I believe there was an MWO that installed a low range reverse lockout on “most” of these trucks to prevent shifting into reverse while in low range. If the seller is very experienced with these trucks I would be a little leery if this issue can’t quickly be resolved, especially with the whining noise.

Thanks! Yes, that's where I stand right now. If it is something simple, I am ready to go! But, not if its going to turn into a money pit/project.

I will ask him about the transfer case being in low range.

 

[CaptainBillUSMC]

Do you have any more info/description on “play in the shifter cable”, or “not going into reverse smoothly”? IE, did you have to work the shifter back and forth, play with the throttle, just took a while to engage? Was the play on the transmission, or shifter end of the cable?

Unfortunately, I don't have anymore info. He told me via text. I didn't ask those questions. I was more concerned with whether he thought it was a difficult fix or not. I did suggest to him that it maybe because it sat for a bit. He wasn't sure. I will ask him. Thanks!

 

[CaptainBillUSMC]

Theres no chance the transfer-case was in low range is there? I believe there was an MWO that installed a low range reverse lockout on “most” of these trucks to prevent shifting into reverse while in low range. If the seller is very experienced with these trucks I would be a little leery if this issue can’t quickly be resolved, especially with the whining noise.

I spoke with the owner. It was not in low range. It was definitely in high.

 

[CaptainBillUSMC]

Do you have any more info/description on “play in the shifter cable”, or “not going into reverse smoothly”? IE, did you have to work the shifter back and forth, play with the throttle, just took a while to engage? Was the play on the transmission, or shifter end of the cable?

The play in the shifter cable he was referring to was where the cable meets the linkage at the transmission.

He didn't have to work the shifter at all. He said it clunked into gear and seemed a little loud.

Could the clunking into reverse be related to a high idle? He did NOT take note of the RPMs at idle though.

 

[ericp351]

Sounds like your communication with seller may take longer than a simple check. That said- since you have reverse, I'd try warm, then test with good oil level and drive to N, then Rev. That is find out "how does she work when super babied "? Also smell check your fluid and figure if Motor Oil ("harsh"), or Trans fluid (relatively easy shifting). Good luck- If price of truck OK maybe take a chance as they stiffen up with sitting. Full retail, your call!

 

[CaptainBillUSMC]

Sounds like your communication with seller may take longer than a simple check. That said- since you have reverse, I'd try warm, then test with good oil level and drive to N, then Rev. That is find out "how does she work when super babied "? Also smell check your fluid and figure if Motor Oil ("harsh"), or Trans fluid (relatively easy shifting). Good luck- If price of truck OK maybe take a chance as they stiffen up with sitting. Full retail, your call!

Thank you!

Thanks! I’m going there on Friday after this snow moves through to see the truck and help troubleshoot. Tough to troubleshoot this kind of issue with one person. I can remember when I was in, the preferred fluid was DextronIII, the red stuff. Not sure why anyone would put oil on there. In the winter that’s going to be rough on the Xmission. But, I’ll check that as well. I meant to ask him that question when we talked today. The price of the truck is very good. Well below market value.

 

[CaptainBillUSMC]

I spoke with the seller today. There is a bit more to the story that I wasn’t aware of. The truck has been sitting for 5-6 years. When I get it home, I’ll need to change all the fluids and probably clean the fuel tank. That’s if I buy it. Figuring out why it clunks into reverse and the whining sound is priority #1 before handing over any money. He said the Xmission fluid is good. Looked good, was over full, and smelled normal. But, after sitting for 5-6 years, I can only imagine how stiff everything is.

I’m going this Friday after the snow we have coming to see the truck for the first time, drive it, and help him troubleshoot. He knows and understands that I’m not interested in a headache project. I’d like to wash it, change fluids, and drive it, if I decide to pull the trigger.

I appreciate everyone’s insight so far.

 

[98G]

Thank you!

Thanks! I’m going there on Friday after this snow moves through to see the truck and help troubleshoot. Tough to troubleshoot this kind of issue with one person. I can remember when I was in, the preferred fluid was DextronIII, the red stuff. Not sure why anyone would put oil on there. In the winter that’s going to be rough on the Xmission. But, I’ll check that as well. I meant to ask him that question when we talked today. The price of the truck is very good. Well below market value.

The military frequently used 15W40 motor oil in the transmissions.

I'm reluctant to change transmission fluids without overt need. I've seen too many instances where one of these is operating fine and then the transmission is changed to dex 3 or straight 10 weight and then there are transmission problems. Enough of a sample size to convince me it's cause and effect...

 

[CaptainBillUSMC]

The military frequently used 15W40 motor oil in the transmissions.

I'm reluctant to change transmission fluids without overt need. I've seen too many instances where one of these is operating fine and then the transmission is changed to dex 3 or straight 10 weight and then there are transmission problems. Enough of a sample size to convince me it's cause and effect...

Really? Wow! So Shell Rotella for example in the transmission? Is that not a concern in the winter? This is good insight! Thanks!

 

[98G]

Really? Wow! So Shell Rotella for example in the transmission? Is that not a concern in the winter? This is good insight! Thanks!

My understanding is the military was wiling to take a hit on service life to simplify supply chain logistics.

I speculate (and that's all it is, speculation) that changing the transmission fluid doesn't completely empty the transmission (torque converter) and that dex 3 doesn't play well with 15w40 mixed in with it in the conditions inside the transmission. I've seen multiple instances where someone got an auction truck and drove it home without issue, discovered it had 15w40 in it and felt obligated to swap it out , and a couple hundred miles later lost the transmission. (I don't have any examples. This has been ~10years ago when 939series trucks were in copious supply at auction.) I'd figure out what's in it, and replace like for like if you feel obligated to put new fluids in it. But I'd leave it alone unless there's some indication that the fluid needs changed. (My opinion, formed by recovering literally dozens of these trucks from auction, frequently picking them up in Ft Riley KS and driving them to Tucson AZ.)

 

[ericp351]

As to trans fluid--- My low miles truck still serves well with the military motor oil. Needs to warm up to be at all smooth, Runs cool , even loaded in summer. Gut feel is tires and or sticky brakes your bigger concern now. Good luck, again.

 

[CaptainBillUSMC]

My understanding is the military was wiling to take a hit on service life to simplify supply chain logistics.

I speculate (and that's all it is, speculation) that changing the transmission fluid doesn't completely empty the transmission (torque converter) and that dex 3 doesn't play well with 15w40 mixed in with it in the conditions inside the transmission. I've seen multiple instances where someone got an auction truck and drove it home without issue, discovered it had 15w40 in it and felt obligated to swap it out , and a couple hundred miles later lost the transmission. (I don't have any examples. This has been ~10years ago when 939series trucks were in copious supply at auction.) I'd figure out what's in it, and replace like for like if you feel obligated to put new fluids in it. But I'd leave it alone unless there's some indication that the fluid needs changed. (My opinion, formed by recovering literally dozens of these trucks from auction, frequently picking them up in Ft Riley KS and driving them to Tucson AZ.)

Ok thanks!

You are probably correct. Back in the "rear" getting and having Dex3 is simple. But, when deployed, it becomes an issue. Combat logistics would be even more difficult. Just like when they switched over to putting jet fuel in the trucks. Much easier. There was a time when the Marine Corps was putting JP5 in everything to simplify logistics.

Are you just talking about the transmission fluid or are you talking about all the fluids?

Thanks again for the advice. When it comes to maintenance, I am a by the book guy so having people with practical knowledge is very helpful.

 

[Mullaney]

Ok thanks!

You are probably correct. Back in the "rear" getting and having Dex3 is simple. But, when deployed, it becomes an issue. Combat logistics would be even more difficult. Just like when they switched over to putting jet fuel in the trucks. Much easier. There was a time when the Marine Corps was putting JP5 in everything to simplify logistics.

Are you just talking about the transmission fluid or are you talking about all the fluids?

Thanks again for the advice. When it comes to maintenance, I am a by the book guy so having people with practical knowledge is very helpful.

.
"Are you talking about the transmission fluid... All The Fluids"

No. Just the engine and transmission.
Other gear boxes are generally 80/90 gear oil.
The power steering could be different too...

 

[CaptainBillUSMC]

As to trans fluid--- My low miles truck still serves well with the military motor oil. Needs to warm up to be at all smooth, Runs cool , even loaded in summer. Gut feel is tires and or sticky brakes your bigger concern now. Good luck, again.

Thanks!

So, you don't think I should be concerned at all about the loud clunk in reverse? And the whiny sound?

Yeah, I will be heavily scrutinizing the tires on the truck. And, of course the brakes and just about anything else I can visually see.