Steering Problem

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U404S
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Steering Problem

Post by U404S »

I bought an M37 several years ago as a hobby project. Finally, I'm getting started on it after a several false starts. One of the things I have been wondering about is the steering. For some reason, the truck pulls heavily to the left; so bad it takes a lot of strength to get it off the trailer and turn it slightly to drive it in the garage.

The strange part is I put some AVM lockout hubs on it and the steering improved to the point it was in perfect alignment, drove true and was able to turn left and right with no issues or effort. If I lock the differential back in with the hubs, the steering goes back to being unusable.

The gentleman I bought the truck from told me the owner before him had Detroit Lockers installed in the front and back axles. I have the receipts from that so I know it happened. I have also noticed the back tires skid and pop through a turn so the lockers are definitely in there. Since I can't really steer it with the hubs engaged in front, I'm not really certain if the locker up there is working right or if it is something else. Because the AVM lockout hubs relieved the issue altogether, it makes me think it is a locking differential problem. Thoughts?

Anyway, I probably ought to just find a replacement front axle assembly with an open differential, but I was wondering if anyone ever had a similar experience with a Detroit Locker in front or if there is something else going on? I also don't care much for the back skidding and kicking on pavement much either. I think I will end up with a broken axle shaft with much more of that. I have a Unimog 404 S with mechanical lockers and the manual states no driving on pavement with the differentials locked. Maybe these Detroit Lockers actually release at some measure of torque, but it doesn't feel like it.

Otherwise, I have to put the front fenders on, the new windshield assembly and the VPW hardtop (finally found the instructions), so I have other things to keep me busy. Just thought I'd post on this axle conundrum in case anyone has some insights. Next weekend the truck goes up on jack stands so I'll be able to study it more. I have all of the TM's too, so I'll start familiarizing myself with the details as well.

I'm in Jacksonville, Florida and if anyone knows of a good spring shop to recommend (front springs super saggy) or has a derelict M37 variant I could buy for some spare parts, drop me a line.

Cheers, Jerry
06boblee
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Re: Steering Problem

Post by 06boblee »

Detroit lockers are not recommended for the front axle as they will "lock up" at the slightest turn- as one wheel turns faster it a turn. I have seen steering wheels pulled out of hands with lockers. They are not as bad if you are in dirt only- one wheel will slip in the dirt releasing pressure on the locker. Still not good.
They are great in the rear, you could swap with someone for an open differential- easier than a complete axle swap! (front and rear differentials are the same)
Last edited by 06boblee on Thu Jul 06, 2017 4:53 am, edited 1 time in total.
'54 M37 wew
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U404S
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Re: Steering Problem

Post by U404S »

Yes 06boblee, Good comments and makes sense on the front-end locker piece. Sounds like a good way to end up with broken thumbs.

I sent a feeler out to the local military museum. It may be that from time-to-time they are contacted by people trying to figure out what to do with stashes of parts or old army trucks. Maybe I'll get lucky and connect with someone to do a differential swap or just get some semi-local parts. Something is sure to come along. Thanks, Jerry
MSeriesRebuild
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Re: Steering Problem

Post by MSeriesRebuild »

Experience speaking, Lockers of any kind are not a good idea in a front axle, PERIOD. We have installed them at customers request, but not without a heart to heart talk about what is to be expected first. ARB air lockers are the best to use if you can't live without it in the front, as these can be disengaged when not needed. If wheels are locking and dragging, you have major issues around the corner, something is not done right. Detroit, Lock-rite, or any fully automatic locker that can't be disengaged is not good on pavement, front or rear, they will cause axle shaft breakage and high stress on differential internals at best. ARB is the only one we use in trucks where a locker is needed, the others simply cause too many problems. Unless there is a real need, we don't recommend lockers.
Charles Talbert
www.mseriesrebuild.com
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