M151A1 Transmission Issues

[tfparis]

My M151A1 will not go into reverse. I was sure that someone had removed the top plug and the pivot had dropped into the transmission. Removed the top of the trans and that was not the issue. Now I am stuck. Not sure what could be causing the issue. All other gears work fine. Just no reverse. would appreciate any suggestions

[W. Winget]

Had a friend's MUTT do this on a replacement transmission that had set up a while.
I removed the top cover, manually pushed the gear back and forth a few times to loosen it, then it worked fine.
It's the rear most left side gear assembly, should move under finger pressure but may take a large screwdriver to get it free.
V/R W Winget

[Rickf]

You say you were concerned that someone had removed the shaft pin, Does this mean it has been in for service and came out this way? It is possible that what you describe did happen and they put the pin and fork back in but did not get the fork on the shift collar on the gear. Can you move the fork back and forth by hand? With the engine running if you move the fork does it grind as it contacts the gear? (Clutch out) If it does not then it is not on the shift collar. If the top cover is on try putting it into reverse without using the clutch with it running and see if it grinds, if it does not then the shift arm is not in the collar.

[W. Winget]

For reference, in the case I described above, the jeep drove fine in all gears but would not shift into reverse using the shift handle.
I then removed the top to check forks, etc. but compared the action of the old transmission (good one) and saw the gear was sticking on the new transmissions shaft such that the shifter cane could not apply enough leverage to move it even with the forks properly engaged. A little tapping with the wood end of the hammer handle and tossing it back and forth with screwdriver resolved the sticking issue.
FWIW
V/R W. Winget

[brush_buster]

Have a similar issue. My jeep has been sitting for several years and I can't shift the gears. Looking for suggestions.
Thanks

[markrdje]

Maybe using slick 50 on it will help?

[Rickf]

Have a similar issue. My jeep has been sitting for several years and I can't shift the gears. Looking for suggestions.
Thanks

It is usually not in good taste to jump in on someone elses thread and ask about your own problems before they have even answered but this person checked in a week ago and has said nothing about our suggestions so I will reply to your question, But I do suggest you open a new thread on it. If the mutt has been sitting outside and you live in an area with high humidity and constant temperature changes then I will guarantee the transmission has water in it from condensation and the transmission top where the shift rods are is all rusted up. Have you had the top off of the transmission to check it out?

[W. Winget]

Rick:
It's pointless, if it's been "sitting for several years", it's going to need the fuel system, brake system, batteries, and transmission checked out, so recommending anything short of "have you looked at it" won't resolve the issues the poster has.
Nice recommendation though.
V/R W. Winget

[brush_buster]

All of the above have been done except looking in the transmission. I had siphoned off the gas before putting it in storage and periodically put the charger on the battery which had already had the cables unhooked.

Sorry I broke the rules. Since the OP was basically having the same problems, I didn't realize my post was in bad taste. Normally, on forums if I post a new thread with a question, the first thing members say is have I used search since the subject probably has been discussed before. This was already at the top of technical knowledge.

Thanks for all your suggestions.

[Rickf]

I don't think you really broke any rules. It is just that the O/P never answered before you jumped in and your situation was a lot different from his. It sounds like his was running and went in for service and it sounds like your is not running and has not been for a long time. In both cases we did not get enough information to really make any kind of real diagnosis. I don't know why W.Winget was so harsh since there was really no call for that but sometimes people just have a bad day. You would be amazed at how many people get mad at us if we do not nail their problems in one shot. Over the internet, sight unseen and based on sometimes not so accurate information. Matter of fact sometimes the information we are given here is very far from the truth and we find out the real info on other forums where that person has gone later to try their luck there. They do not think that most of us mechanics are on all the forums. LOL.

[W. Winget]

Appologies if I seemed harsh, reality is, vehicle as described has a long prep with PMCS before the transmission can be checked.
V/R W. Winget