Just finished replacing front and rear brakes, and a blown power steering line, on my '00 2wd 2500.

While doing the rears (not half bad, compared to my other truck, a '60 international 1 ton..) I realized the rear diff isn't acting right.

This truck has the "anti-spin" LSD (and 4.10 gears).....but to my knowledge, that's NOT a locker. (I'm familiar with how clutch pack LSDs work)


Anyway, as it sits right now, in neutral, spin 1 rear wheel, BOTH rear wheels spin. Block 1 of them, and NO rear wheels spin. About 1/16 of a turn is all you'll get. It did this both before and after the rear brake replacement, so I don't feel it's related to that.


I crawled around under it to make sure there wasn't a locker installed, and I don't see any wires or air lines going in, other than the rear axle ABS plug (and I confirmed the truck DOES have rear ABS).


Driving the truck, it behaves exactly like a locked axle would....so it's not breaking free when driving. (dragging the outside wheel in turns)


Anyone have any idea what would cause this? Time for a new axle? Obviously, not going to let mom borrow the truck for a 1000 mile tow until it's sorted....


I suspect if I drop the diff cover I'll probably get lots of metal bits, huh...

sigh.

...d

 

Guess you never heard of a mechanical locker?

 

Unless someone snuck into my shop and installed it during my 3 years of ownership, and it doesn't have any method of activating/deactivating, then I dont believe there's a mechanical locker involved.

If you suspect there is a locker in there, perhaps you could suggest a method to -unlock- it?

 

As far as I know, when the vehicle is up on jacks and you spin one wheel , the other one will spin in the same direction if it's a lsd, as opposed to a corporate 9.25 which will spin the other wheel in the opposite direction. You have no problem with driveability, so what's the problem?

 

My response was specific to this comment: "I crawled around under it to make sure there wasn't a locker installed, and I don't see any wires or air lines going in..."

That would tend to indicate that A) You think all lockers are air or electric actuated, and B) You are unsure of what may be inside your pumpkin.

A mechanical locker like the Detroit Locker works automatically.
http://www.eaton.com/EatonCom/Produc...cker/index.htm

If it has malfunctioned it can behave as you've stated. An LSD that uses fiber clutches would probably not lock up like that. I suggest you drop the cover and see what's going on in there before you do any more damage.

 

a lack of fluid or contaminated fluid (water) could cause a mechanical locker to overheat and fail. and if the gears are seized together then it would act as a solid axle.

 

Since reading the post again, I guess there is a driveability problem. oops! besides he pretty much answered his own question, by saying "I suspect if I drop the diff cover I'll probably get lots of metal bits, huh..."

 

did you service the axle recently and fail to use a friction modifier in the oil?

 

Mine has the LSD and does this.

Ok, mine DOESN'T do that.

 

Back in the old days we used to call this type of differential 'positive traction'
which I'm sure they just gave it a new name, same old thing.

They do result in slightly more tire wear regardless, because it always gives a little power to
the other wheel, but it shouldn't be completely locked, no.
This type of differential, to my understanding never locks, all it does is apply some power to the
non-spinning tire, however when enough throttle is applied it can result in both tires spinning.

Try a really tight turn, far as the wheel takes it, see if you can hear squealing (might have to
take it over a specific section or type of pavement, dirt or gravel would probably work).