I installed my 8" trac-loc. the pig was complete when I purchased it. I didn't have the vibration before I put it in this weekend and it happens when I let off the gas and coasting. when I'm on it it's not as bad. also the rear seems tight (binding) around corners. is there a way to see if the rear is set up too tight without removing the 3rd member or is this normal for a posi? also the drive shaft seems too short. there is a 2-3/16" gap between the tail of trans and the front of the u-joint. is this normal and could this be the cause of the problems?
The driveshaft is not in the transmission far enough causing the vibration. You can change to a longer yoke on the pig but then you will need the correct U-joint to fit the yoke. Might be cheaper to have a new shaft made.
Pinion bearings going bad will cause vibration while coasting.(among other things)Is this the same drive shaft you had in the car with the old chunk??? As for the binding...could be carrier side play is adjusted too tight.I would pull it and have it checked out.Sounds like it may have a few issues.
same shaft, pinion bearing? the drive shaft is the same one. is there a way to see if the pinion bearing is the prob? should I try the longer drive shaft first? and then work my way down from there?
trac loc forgot to ask... could driving it with the posi side play being too tight cause any big problems?
Too much pre-load will kill the carrier bearings.As for the yokes,If this one is different from the old one you had in the car as rthomas pointed out it will cause your vibration since it isnt allowing the front yoke to ride in the tail housing bushing where it should be.A longer shaft will cure it too if this is the problem.Good luck.
preload is there a trick to see if there is too much pre-load in the posi... put it up on a jack and try ?????
is the yoke on the center section you removed the same length as the one on the center section with the trac-loc?
Really need to take it out to check it properly.check your yokes...see if there is a difference.I am betting thats your vibration problem.As for the side loading or binding...Sounds like a problem that will require removal and inspection by someone who does diffs for a living.The pre-load on the carrier bearings affects how the ring and pinion gears mesh.If its too tight it will eat the gears in short order and they will be nothing but noise.The clustch pack in the diff may be at fault too as far as the binding is concerned...Did you put a posi additive (friction modifier) in with the gear lube when you filled it back up??? The additive keeps the clutches from being grabby and helps them live a long happy life.
can a drive shaft be lengthened? there is 2-3/16 of shiney input shaft showing now as before it was out about 1-3/4". as far as the rear I know there was a very little play between the gears... not too tight. and yes I put the friction midifier in. should it work immediately or does it take while for th e gear oil to work it's way into the clutches? I have about 3 miles on it.
You can change the yokes you know.put your old yoke on the new chunk.Just dont use an impact wrench to install the nut.Put about 70 ft lbs on it and leav it alone.too much torque and you will trash the pinion depth setting.Too little and you will trash the depth setting.The proper yoke should put your drive shaft back to the proper depth.I have to add at this point...Depending on the type of posi unit you have.It may just be a bit grabby feeling when it goes around corners.Some are noisey...Some feel grabby...Some are allmost totally un noticeable around corners.If the clutches are fresh...it may take a few miles for them to work in.Drive it after you solve the drive shaft length problem and see how it behaves.
Does it have new clutches?? Sometimes they need some milage to stop grabbing on turns. Fix that driveshaft and put some miles on it.
I would point out that when you reinstall your driveshaft, it is possible to overtighten the u-bolts that hold the joint to the yoke. If you already knew that, then great. If not, you might think about that. I have made that mistake before. If you DID overtighten them, the joint is ruined and must be replaced now. I would crawl under there and give the front and rear of the shaft a good shake side to side. That would expose a loose fit in the tranny, a bad u-joint, or any wobble in the pinion that would indicate a bad pinion bearing. If there is any lateral play in a part, there is a problem. Also, swap the yokes if there was that big of a difference. Just don't overtighten the bolt as posted earlier, so you don't change the crush depth. Hope it is something simple.
