1984 Chevy Truck Backlash adjustment on pinion

DAVID BRIGHT

MEMBER
1984 CHEVROLET TRUCK
V8
4WD
AUTOMATIC
200,000 MILES

I am repairing a 1984 chevy 3/4 ton 4x4. Man brought me this truck, rear inspection cover removed, and driveshaft removed. Said he had been driving it like this for a while off the front axles. I pulled the axles and the third member out and found a broken pin and broken spider gears. Ring gear and pinion gear looks ok. Third member bearings seem good. Found spider gears and pin at local junkyard. I put third member back together and installed. I installed shims and spacer the same as they were when I took it apart. When I adjust the sleeve to were it rolls smooth and I snug the saddles down, It puts it in a bind. I realize this is a critical adjustment and if not done properly can ruin a rear-end. Is there an easy way of adjustment? Thanks

1 Reply

DCS1998

MEMBER
41 POSTS

To answer your question, there is no easy way.

I had a '84 (Broke pin and spider gear and messd up carrier), took the ten bolt out and put a '78 GMC 12 bolt in. It sang like a bird!
Went to the Dealership and got every carrier and pinion shim the had in stock plus a new "crush sleeve" for the 12 bolt.

Long story short, it took SEVERAL days and nights to get it right. And I worked in a machine shop for 25 years!

But it sounds like you have too much shim on the ring gear side of the carrier, too much pinion shim between the large bearing and the pinion or you havent torqed the pinion nut down (it is somewhere around 100 ft/lbs) which would seat the large bearing aganst the pinion. MAKE SURE your 'crush sleeve" or spacer thats between the large and small pinion bearings is in place before putting the 100 or so ft/lbs on the nut, as it WILL ruin your bearings.

In short, I would carry it to someone and have it done if you have never set up a rear end before.

If you choose to take a stab anyway, I will help you as much as I can with what tools you will need and such.

David