Hey guys. I have a 67 A100 Van with a Borg Warner (Auburn Gear)
style sure grip in it. Everytime I come to a stop and start out in 1st
gear I hear a loud clunk coming from the rear end.

After hearing this several times I stoped the van on my street and
went forward and backwards shifting from 1st to reverse (3-speed
trans) and it clunks in both directions. I had my dad get in the van
and do this while I watched the rearend. What is happening is, the
van starts to move forward or backwards depending on the gear
selection and then the drive shaft jumps about 3/4" radially. This
is when you hear the clunk. Once it clunks in either direction it
won't clunk again until you change directions again. Meaning, if
you get the clunk in first gear, stop, then start again in first it won't
clunk again. I'm thinking I need a new clutch pack?

Has anyone experienced this with this type of sure-grip?

Thanks
Mike in WA

Wow. That sounds like badly worn pinion bearings or a collapsed crush sleeve/shim spacer. If the driveshaft is jumping 3/4" off axis, then I don't think it could be the clutch packs.

Are you sure it's not just the driveshaft rear U-joint?

Hope this helps,

Lou

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Home of Slant6-powered fun machines since 1988

If I read this correct, there is a bunch of free play in the rearend and you have to get thru it before things go again. What do you see / feel if you move the driveshaft / rearend yoke by hand? Do you get 3/4 of a turn of slop? (free motion)

If it is an Auburn type limited slip then it is a cone type posi and the cones could be worn-out, that causes lots of freeplay, like loose spider gears.
Sad to say that cone type posi units are not rebuildable.
DD

I may have misunderstood. I thought the driveshaft was moving radially away from its centerline, not turning 3/4" around its axis.

Hmmm,

Lou

_________________
Home of Slant6-powered fun machines since 1988

Doc,

I just saw in the Mancini Racing catalog that they now have rebuild kits for Auburn gear LSDs! It's a new product. So, I'd call Mancini Racing to see what it's about if a rebuild of the unit is in order.

Pat

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'68 Dodge Dart 4dr Sedan

I have also seen those so-called "rebuild kit". I have been doing that little trick for years using modified driving shell / sun gear shims out of auto trannies.

This kit has 2 big washer you stick in between the cone and the side gear, yes it does take-up some of the freeplay but does nothing for the worn cone and case surface.

On badly worn units the cone will have bottom-out on it's "face" and at that point you get little to no "limited slip" control out of the unit.
$30.00 for the "kit" is cheap so you should give it a try, get the thickest washers, I think they come in .030 & .040 thickness.
DD

Doc, back in my crazier machinist days, I used a lathe with a tool post grinder to refinish the tapers and dress the bottoms for clearance. It can be done. Is it worth it, probably not.

_________________
'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

I forgot to ask, have you checked to make sure the pinion nut has not backed off?

_________________
'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd