m925a2 will no longer shift out of neutral

[captain]

I ran in to a problem today that I really need to get fixed before next weekend. I have not had the truck long but the few times I have driven it I have had no problems other then it has very little power. I went to use it today and it will not shift out of neutral. The release on the shifter shaft pulls up fine but something is holding it from moving. It has always shifted into all the positions well and has driven smoothly. Does anyone have any ideas as to what could have suddenly changed to lock the shifter in place? I tried to search but only found t-case issues.

Thanks.

 

[m16ty]

Sounds like you have a linkage problem. Crawl under the truck and look at the linkage. I bet the T-case interlock that is supposed to keep you from shifting to reverse in low range is fouled up. I had a M932 that this was out of adjustment and locked the shifter in first get and wouldn't go to neutral.

 

[M925]

Have you checked the Technical Manual?

Sometimes when they spray bomb paint has to be removed. You may have low fluid.

NO RESPONSE TO SHIFT LEVER MOVEMENT - Continued
STEP
1. IS TRANSMISSION FLUID LEVEL CORRECT?
Visually check transmission fluid level (Volume 5, WP 0820).
T1040DAA
ACCESS
DOOR
DIPSTICK
HANDLE
Figure 1. Transmission Dipstick.
CONDITION/INDICATION
IS TRANSMISSION FLUID LEVEL CORRECT?
DECISION
NO - Add fluid as necessary (Volume 3, WP 0362). Go to Step (5) to verify problem is solved.
YES - Go to Step (2).
TM 9-2320-272-23-1 0034
0034-2

Etc....I lost my place in the TM, but it's in there.

 

[Suprman]

Make sure your hi low range lever is all the way in the down hi range position. As far as the power goes it should have torque but they are not fast vehicles by any means. I believe the tm has a troubleshooting procedure you can follow

 

[captain]

Thank you all for the replies. So there is nothing in the shift tower or attached ctis box that can lock the shifter in position? There is no neutral safety switch or anything that prevents it from releasing to shifter like a car has? The T-case lever is all the way to floor. I never moved it but I did check to make sure it was down when I had the issue. The fluid level is full. I will triple check it though. I will also look at the linkage. Its just odd that it worked fine last month and now it just wont work at all. I will read through more of the TM's tonight.

As far as power goes I do not expect it to be fast. I'm just baising it off what others have said that they can maintain 65mph. It takes me about a mile to get to 35mph. It can just about maintain 45. It could be something as simple as the throttle stop or something else preventing full rack travel in the injection pump. I'll look into that over the winter when I get some time. I'm more concerned about finding and fixing the bad axle seal causing a oil leak out of the air lines.

Thanks

 

[Suprman]

There is a neutral safety switch but it prevents starting when you are not in neutral it does not affect shifter position. The truck should be able to get to 35mph easily and it may take a mile to get to 60 when getting on the highway. If oil is coming out of the ctis quick release valves then you have a blown ctis axle seal. On the back of the motor there is a drain tube it kind of just hangs down. When your engine is running is anything coming out of the tube?

 

[BKubu]

In high range, the 6CTA has little power from a dead stop. Once the truck gets rolling, and the turbo starts to spool up, the truck should pull nicely. Every time I pull out somewhere, I am disappointed by the power. Now, in low range, the truck has serious power...but most of us run around in high range almost all of the time.

 

[BKubu]

With regard to the power, have you changed your filters? If not, do so. Also, make sure you burn any old fuel through or empty it out (which would be better). I also suggest adding some good diesel conditioner.

 

[ichudov]

With regard to the power, have you changed your filters? If not, do so. Also, make sure you burn any old fuel through or empty it out (which would be better). I also suggest adding some good diesel conditioner.

Bruce, which filters would you recommend changing, specifically?

 

[BKubu]

Depending upon your truck, it can vary. Your truck may have the older (but better) and recently retrofitted M809 series filter under the fender. There should also be a spin on filter located on the driver's side of the block (back toward the firewall). Then, there also may be a small inline filter leading toward the spin on filter. The M939A2s started out life with one spin on filter, but the military found that it clogged too quickly and so they added a small inline filter that is supposed to take the brunt of the junk in the fuel (the idea was that this small inline filter would be changed more often). Then, the military started to retrofit some of the trucks with the older and larger fuel filter found on the earlier M809 series trucks. I have never seen a truck will all three...M809 series filter, spin on, and inline...but I bet they exist! Most of my trucks have the spin on and inline filter, but some of the recent rebuilds got retrofitted with the larger M809 series fuel filter...not all of them got it, however, as I have a rebuilt M923A2 in my yard right now that did not get it. I don't have the filter numbers here, but I am sure you can search this site for them.

 

[captain]

I was able to get to my house tonight and take a quick look at the truck. This was all with the truck off so I have no idea if it will shift through drive positions or not when its off. I tried moving the t-case lever between the 3 positions. It still will not shift. When the shift position lever is wiggled the cable to the trans moves but the arm on the trans does not move at all. Does this indicate something is wrong with the transmission its self that is not allowing the shift arm to move?

 

[Suprman]

I have never had a trans issue like you are having but if you can disconnect the shift cable from the transmission and the shift arm going into the trans is frozen that would probably indicate a trans problem. Maybe that's why you are lacking power. Did you check the fluid and level. You have to check it in neutral with the engine running. Dropping the trans pan might be a good starting place then maybe you can see what's going on in there look for metal in the pan and filter.

 

[captain]

I did not check it this time since I could not drive it to get it hot. Last time I drove it it was full and clean. When I can get a chance I will remove the cable from the arm and see if it will move on its own. Since the cable jumps when you wiggle the lever but the arm does not I suspect this will end up just one more vehicle I cant use.

 

[captain]

I got over to the truck last night to have a look. I managed to get the shift cable separated from the shift lever and shift arm. The arm on the trans moves fine and the lever moves fine. The cable is locked up for some reason. Thanks for the help in tracking this down.

 

[Suprman]

Take off the 4 bolts that hold the shifter in and it will lift right out the cable has some room to pull it all up. You will be able to see if its a bad cable or the shifter assembly is bound up.

 

[captain]

I was able to get the shifter out last night and disconnected the cable. The shifter moves fine with the cable off. I am going to try to get the cable out tonight. I just find it very odd that the cable locked up with no indication of it going bad. It was never rough or gritty to shift. Always smooth.