So I am getting ready to tear into my rear end. It howls at low+ speeds, so I assume it is the pinion bearings or preload. Took the cover off and gears are good and wear pattern looks good. Internet is full of wrong info on identifying GM rear ends (especially Buicks), but I assume this is an 8.5 based on the 2 sticky-outs at 5 and 7 o'clock. My questions are: 1. How easy or what tools are needed to pull the axle shafts out (it has the bolt-in rear axles, not c-clips). Service manual says use the GM special tool to pull them out, which were probably all melted down 40 years ago. What else might work? 2. If it is stock (3.08) and never been messed with and I am putting the same gears back in, is it safe to assume that putting all the same shims back in will give it the proper tolerances without having to do all the measurements?
Yes the rear pictured is 1971 1972 Buick/ Olds 10 bolt 8.5 Corporate rear . Axle shaft should come out pretty easy... You can use the drum flipped trick as a slide hammer ...but be careful if you hammer too hard you can tweak the drum... a big steel chain can do the same thing...OR get slide hammer the proper way. Beating on the axle flange edges is not normally a good idea. If the wheel cylinder was removed you can use a 1/2 -3/4 steel 1-2 foot long drift to hit the flange from the back side also keep it closer to the thick radius parts of the axle shaft . Shimming and noise. - Normally if you KNOW for sure the 3.08 gears are original to the rear and they are quiet YES just put all the original shims back after replacing the bearings should be good again.... BUT be sure you have found the noise culprit before trusting the gear set is not the one making the noise... Jim
Jim, will popping the axles out mess up the wheel bearings or seals? Seals currently don't leak and it would be great to retain them. Of course, the whine may be a bad wheel bearing, but the wheels are pretty smooth and quiet when you turn them. Thanks.
All depends. If they are really stuck and hard it could mess up the seal...bearings should be fine...BUT again that is for you to inspect. Jim
Once the axles shafts are out one way to tell IF the bearings are bad is to just spin them by hand & feel/listen for roughness. IF, there is any roughness/noise get new bearings & go to the machine shop to get the old bearings pressed off & the new ones pressed on. Just check on this site posted by Larry'70Gs on how to identify your getting the proper seals or bearings OR to be absolutely sure get them from Jim. Tom T.
Thanks folk, guess I'll start tearing into it. By the way Jim, I always thought a Monza would be super cool to beef up (I always liked their egg-shape), but I'm out of shop space.
if its truely the pinion bearings. once you pull the carrier and turn the pinion the noise should still be there, if you turn the pinion and the noise goes away after carrier is removed it's in the carrier. try to measure backlash b4 tesori g apart to try to match. pinion noise normally will come and go when driving when to apply and let off the tbrottle
Yah... I like them... But really long ago it was cheap and light and did not have to build much motor to keep up with the other guys...Just kind of grew on me after 25 years...lol. I have another spyder that was suppose to get on the street...Looks like daughter #1 will be taking that one for the track. We are just taking the LS and installing it in to the s-10 J D Race track for a runner and stock weekend warrior for a little wile... The s-10 has seemed to become the monza /vega of the day... light truck with lost of aftermarket support for motors and such. Oh well...
JMOHO... You may find it easier in the long run to bite the bullet and spend 2 hours and just pull the whole rear end out of the car. Unless you have a rack to work under, youre gonna find its a bunch of crawling around that a lot of us cant tolerate any more. Put it up on two horses and work like a mechanic, and not a kid. There are diagnostic noises to help figure out whats what. Whining all the time, coasting, accel or decell, turns, EVERYTHING must be checked as it comes out. Dont just "tear into it". Check the real basic stuff first, like is it full of oil, or are the U-joints dry, you know, the stupid stuff. Follow the BOOK. TOOLS?? If you have trouble pulling the axles, are you gonna be able to read backlash with a dial indicator? Do you have an inch pound wrench to check the pinion pre-load and reset it going back together with either a new or the used crush collar? An impact wrench to collapse the colllar? If you change the lower bearing (the one farthest inside), youre gonna have to check all the depth stuff and maybe adjust the shim pack. Theres the back lash shims on either side of the carrier. DO NOT MIX THEM UP. If it needs 1 or 2 carrier bearings, all the shim adjusting will need to be rechecked/redone. If the pinion bearings are bad, is the seal leaking? All this dirty greezy work, and you have to maintain a clean room atmosphere making adjustments. Now would also be the time to box the lower arms and install a sway bar.. just sayin' on theat. Its always easier to spend someone elses money eh? I had the differential outa the '72 last year for a cursory exam. It was good. I did it for piece of mind, plus some cleaning and U-joints/suspension. Good luck with the job Doc! If you can do it, thats one more notch on the gun belt! ws
one benefit to leaving it in the car especially if working g by yourself is first not having to man handle a fully loaded housing. second when you go to crush a new crush sleeve leaving the housing in the vehicle will hold it in place, you wont be having to worry about it moving when your trying to put several hundred pounds of force into crushing a new sleeve
Lost my engine-pulling, heavy-lifting helper when my youngest daughter ran off to college, so I won't be pulling it. When I first got the car, pinion seal had leaked all the oil out. I replaced seal, refilled, put in new u-joints, and checked preload. I'm starting to think more along the lines of a bad carrier bearing now (noise coming from diff when axles spin but pinion is not moving.. kind of a crunching sound). I've done all the measures and shimming when putting new gears in before, but I was hoping for an easier job on this one (and I've never dealt with bolt-in GM axles). I'll check lash, etc. as I tear into it. Time to dust off my old dial micrometer. I see I'm not the only one who paved their shop floor with cardboard boxes.
if it's a wheel bearing simple removing the axles will make the house goes away....spinning b4 removal then after to see if any difference in sound
Numbers match that for a 71 GS. Brian, just noticed you're from Erie PA. My Nephew just started his medical residency in one of the hospitals there. He's from Austin, TX and never really dealt with cold or snow much so I guess it is a crash course.
The wheel bearings will be sealed. They don't get gear oil. If you ran it out of oil you likely toasted the gears. They generate a ton of heat.
1970 -1976 BOP A-body wheel bearings are OILED from the center Not seal like 1969 and older. I do not know which guy your answering...But both this 12 bolt olds 1970 and the 1971 1972 lark first pictured are oiled bearings in this thread.... Jim
