Differential question. - Steel Soldiers::Military Vehicles Supersite

Jones · 10-06-2008, 01:41

Well, I may have just wasted a week-end.
The rear axle in the baby HEMTT has what I considered excessive play in the gear train. This was based on the fact that, with a driveshaft bolt hole a 12:00, I could rotate the input flange almost far enough for the next bolt hole to assume the 12:00 position.
Got another differential and this one was much tighter; could only rotate flange far enough to move a bolt hole 5/8" to 3/4" from it's starting point.
After a full day's work swapping out the differential, I'm standing there admiring my handiwork and studying the differential I just removed; clean, bright, I can still see the paint from checking the gear contact and I realize that by looking into the hole in the casting that encloses the spiders I can see a big spring staring back at me. I dive into my 24Ps for both M800 and M900 series 5 tons and neither one shows a spring in the exploded view.
With a sinking feeling I realize that Barstow Truck Parts having been my source for the axles is practically next door to Barstow Marine Corps Base and don't I remember a thread saying that some USMC trucks had locker differentials.

My questions:
Do locker differentials naturally have more play in them than standard non-lockers?
Do these aforementioned lockers work for traction control a la Sure-Grip, Posi-Traction, etc. or do they just "unlock" to make cornering easier on tandem rear axle assembly components?
And, Did I just spend a week-end replacing a perfectly good locker differential with a non-locker?

Elwenil · 10-06-2008, 01:56

Yes, a locker will have more play that a standard diff. It sounds like you might have swapped out a good locked diff. I probabaly would have done the same without thinking about it though, lol.

Jones · 10-06-2008, 02:22

Oh good...
Do the military lockers work like a Posi-Traction or a Sure-Grip?
If so then I guess I know how I'm going to spend next week-end.

Elwenil · 10-06-2008, 04:38

If I understand it right, the lockers are either a Detroit Locker or similar design. They lock when torque is applied through the driveshaft and unlock when coasting.

ssgtwright-usmc · 10-06-2008, 05:15

I am sure someone is going to say (look it up, its been posted before)! Just kidding but thats the replies I have have been getting lately when I post something that I did not know was posted before.
Again everyone, I am joking here now!!!!

gringeltaube · 10-06-2008, 08:10

Yes ssgtwright-usmc, here it goes ....: Jones, see my post here: http://shortlinks.net/xbp805 regarding operation of a Detroit locker which I think is in your diff.
DLs do not unlock when coasting, so better don't accelerate or engine brake while cornering!

G.

Jones · 10-06-2008, 11:06

Thanks guys. Guess I'll be doing a differential swap-- AGAIN, next week-end.
At least by now, I'm getting pretty good at it.