JamesC

iTrader: (5)

Use jack stands to support the car. Remove wheels/tires; allow the axle to hang in such a way that the sway bar doesn’t obstruct the removal of the diff cover.

JamesC

iTrader: (5)

Remove calipers/carriers and rotors (with PBR’s, I simply removed the two carrier-to-backing plate bolts and lay the assembly aside).

JamesC

iTrader: (5)

Remove the diff cover and drain the lube. With the car in neutral, rotate the differential until the pinion shaft is accessible. Note the pinion shaft bolt is above my index finger, the pinion shaft above my middle finger.

JamesC

iTrader: (5)

With the car in gear, remove the pinion shaft bolt. Use a 5/16 six-point box end wrench and dead blow hammer. A couple of moderate whacks should do the trick. If the pinion shaft doesn’t slide out, rotate the differential (neutral) until the top of the shaft can be accessed. I used a tack hammer to gently tap the shaft down a 1/2 inch or so. Rotate the diff again. The shaft should be exposed enough to allow insertion of the pinion shaft bolt. Use it to twist/wiggle the pinion shaft free.

JamesC

iTrader: (5)

Push the axle inward to remove the C clip. A magnet is helpful.

JamesC

iTrader: (5)

Remove the axle. (Don’t move the diff with the axle(s) removed.) Note the wear where the bearing rode.

JamesC

iTrader: (5)

A slide hammer will eliminate the old bearing and seal (the bearing in the pic is an axle saver or off-set bearing and doesn’t resemble the OE, which can be seen further below).

JamesC

iTrader: (5)

Clean the axle tubes. A mop handle wrapped with a clean rag will work. Shoot down with brake clean. Check that portion of the axle tube which houses the bearing and seal for irregularities. Lube the bearing thoroughly with gear oil and insert it as far as the seal shoulder. A driver, slightly smaller than the axle tube, and a couple of moderate whacks with a BFH (I used a four-pound sledge) will drive it in.

JamesC

iTrader: (5)

Lube the rubber in the seal. Square the seal up in the tube. A driver, larger than the axle tube, to insure that the seal will be flush with the tube, and a whack with the BFH will do the trick.

JamesC

iTrader: (5)

Lube the axle completely. Guide the axle into the axle tube carefully so as not to snag, tear, or otherwise damage the seal. With the axle(s) inserted all the way, install the C clip and pull outward.

Lube the pinion shaft and reinstall. I used the tack hammer to gently drive it upward. Insert the bolt in the pinion shaft to align the holes (pic 4), then transfer the bolt to the retaining hole. Push the bolt with your finger while driving the pinion shaft gently upward. When the holes align, the bolt will pass through the pinion shaft. Put the car in gear and tighten the bolt snuggly (the manual calls for 27 pounds).

JamesC

iTrader: (5)

Button up with RTV or a gasket. Refull with fluid, about two quarts, and GM’s limited slip additive (if your car is so equipped) p/n 1052358. Reinstall brake components, wheels, etc.

I used new Moser 26-spline axles and Timken bearings and seals.

By the way, I rented the slide hammer and bearing driver set from AutoZone.

A how-to for replacing the pinion bearing seal can be found in the following link:

https://www.thirdgen.org/forums/tran...ring-seal.html

Thanks to Sonix, jwscab, and sofakingdom. Other tips are welcome.



JamesC

Stevo

iTrader: (45)

Great write-up it should be a sticky. I just did this 2 weeks ago using the same method and everything went smooth. I also rented a slide hammer from advanced auto.

big gear head

I'd like to add a few things.

First, not all axle seals are created equal. Some have a nice coating on them to prevent leaks around the outside, others don't. I always smear a light film of RTV or other sealant around the inside of the axle tube before driving the seal in. This prevents leaks from scratches in the axle tube. It is also a very good idea to check the spring that is inside the seal to be sure that it stayed in place when you drove it in. I've seen them pop out several times.

I always use blue Loktite on the threads of the cross shaft retaining bolt when I put it in. If this bolt backs out you will have major problems when the cross shaft slides out. You will probably total your car, or kill yourself when the rear end locks up.

This isn't a problem on the later rear ends, but the '60s and early '70s cars with the Eaton posi had a big problem with the thrust washers sliding out from behind the 2 pinion gears when you removed the cross shaft. Many people never noticed that the washer was gone and they just put the shaft back in and let it go. This would allow the pinion gear to eat into the soft case and ruin it. It also changes the preload on the clutches and changes the contact area of the gears, which will make them break easier. I just threw this one in for those of you who might also have one of the older muscle cars.

JamesC

iTrader: (5)

The GM bolt has red Locktite from the factory. As I'm a bit **** in such matters, I recommend a new bolt: GM 14056196 ($2.54) or Napa BK6351023 ($4.19).

JamesC

big gear head

Using a new bolt is a good idea. These bolts break often and can be very hard to remove.

JamesC

iTrader: (5)

Any other comments?

JamesC

JamesC

iTrader: (5)

CAUTION: Some members have caused themselves a serious problem when they round the head of the pinion shaft bolt. I'd guess that in most of those cases, a twelve-point box end and/or socket was used along with some yanking, pulling, and grunting. Sure recipe for disaster. ONLY use the 5/16 six-point box end. That and a crisp whack with a dead blow has worked for me every time.

If the bolt is broken, the following tool may be helpful:

http://www.etoolcart.com/fabbri-diff...actor-kit.aspx

JamesC

jb3829

iTrader: (1)

Is the new bearing called a differential bearing? Any part#'s? I checked around my usual stores but no one carries them. I'm looking at rockauto but I want to make sure I'm getting the right bearings. Thanks

JamesC

iTrader: (5)

I purchased my Timkens from AutoZone. Double-check the following:

Wheel Bearing Rear, part #5707
Wheel Seal Rear, part #8660S

JamesC

jb3829

iTrader: (1)

Thanks again James.......I assume the bearing would fit an 84Z 10 bolt? Autozone told me they didnt have anything for that year but the website says different

JamesC

iTrader: (5)

You should be good to go.

JamesC

I H8 WWD

iTrader: (5)

Subscribed for future reference.

bvahnee

iTrader: (2)

Just so were clear, when you refer to "lube" do you mean grease or the gear oil found in the differential?

JamesC

iTrader: (5)

Gear oil.

JamesC

bvahnee

iTrader: (2)

Excellent, thank you.

bvahnee

iTrader: (2)

I just finished installing new wheel bearings yesterday following this write up and it went smoothly. Just a word of advise, rent the slide hammer, there's no way around it, especially on old bearings, that tool saved my ***. Also, if you don't rent the driver and need a way to drive the bearing in, I used an old skateboard wheel and it worked great.

I thought new bearings would help with my excessive rear camber and brake sqeuling around left turns but no dice. oh well

Edit/Update: I installed a new axle shaft and that took care of the brake noise/camber problem. The damn guy that sold me the rear end left out how torqued the shaft was.

twobuy212

I haven't found an anwser to this question anywhere. I need to replace the front seal on my 3rd member(diff.) What is the best way to take this out? I have tried to remove it from the front but the only way I see of doing that is by a little force and bending the old seal than prying it out. Any ideas that are less threatening to the gears.

cIaRmOaCrZo

iv been thinking about replacing one of my axle shafts, both bearings, and seals. the reason is for the axle shaft, i was getting my car dyno turned and the tuner and a kid said my rear wheel was a bit wobbley while making a run. so then i had the rear of car up on jack stands and started it and put it in drive and noticed my driver side rear wheel was indeed wobbley. i slid into a curb 3 years ago and trashed my weld circle light rim on the rear, but i already replaced it...back to subject, to make sure it wasnt the wheel (the new one), i took the wheel off and put the lugs on against the rear rotor and ran it again. sure enough the axle flange is bent. so iv been looking around for axle shafts, but the cheapest NEW shaft i found was right under $200. should i get a used one?? but i dont want another worn out one or even bent one. AND another problem, im not sure if the axle bearings would cause this, but when im cruisin down the road and hit the slightest bump (and i mean SLIGHTEST) it makes a clatter noise. like a sharp "clack" or "ting". its very annoying and very embarrasing. and to narrow it down to the axle bearings, when i had it up on jack stands, i kicked the wheel and it made that "clack" noise. so i cant be suspension components... has anyone experienced this noise or problem???

bvahnee

iTrader: (2)

If you dont want to shell out around 150-200 for a new shaft you can do what I did, buy one on ebay. Yes, as crazy as that sounds, thats what I did. I bought mine off of a seller named "firehawkjeff" (99.9% rating), he owns a parts store called TA Creations USA located in Florida. Now I have a rear end from a 95 Z28 so I needed a late model shaft, but Im sure he sells third gen shafts also.

The chatter sounds like the same problem I had, the bent shaft would actually move the caliper in and out causing a god awful noise coming from the rotor/caliper. It happened on turns and bumps and yes it was embarrassing.

With the new shaft/bearings/seals all those problems went away. Good luck!

cIaRmOaCrZo

i dont think the that noise on mine is comming from the brake system. i had it sitting still and kicked it, and it make the same noise. i think there is alot of play in the c-clips. not for sure of course (or i wouldnt have posted my problem lol) or possibly the bearings are worn to bad. idk

JamesC

iTrader: (5)

If the bearings are bad, the axle probably is as well (Note the wear in post #6). The telltale sign is weeping/leaking from the seal--fluid will probably drip into the inside of the wheel. New Moser axles, BTW, cost me around $230, IIRC.

JamesC

engineman

I have the same car as you restoring and changing engine with a 383 what should i do with the 700r4 and the 273 gears?

engineman

I have 1989 Z28 305 restoring and changing engine with a 383 what should i do with the 700r4 and the 273 gears?

SR-71

Asking this question will get you a long list of opinions, based on what each thinks is best.

I would answer your question with a couple more questions-- What kind of performance do you want from it? What kind of driving do you want to do?

To most guys my build is all wrong. Wrong heads. Wrong headers. Wrong rear gears (3.08). But for what I want-- a high-torque highway cruiser that can still spank a 'Stang. Only goes to the strip for test & tune-- it's all correct.

twobuy212

I used a Stage 1 rebuild kit from B & M for the 700R4 tranny. Works great! I wish I had went ahead and placed the Stage 2 instead of the Stage 1 though.

85 ZXX

iTrader: (1)

Question, How many RPM's @ 100 MPH with the 3:08's?

SR-71

I have paid a lot of attention to this question as I planned my engine build, 'cuz I wanted to maximize fuel economy while keeping acceleration and top speed. So I ended up building my engine for low-end torque and stuck with my 3.08's.

RPM per speed depends not only on the rear gear, but also the transmission gearing, and tire size.

My Formula has the WC T5 trans with the 0.63 top gear option. So far, I have stayed with the Formula stock 245/50R16 tire size. In top gear, I get 130 rpm per 5 mph, or 38.5 mph per thousand rpm.:

MPH RPM
55 1430
60 1560
65 1690
70 1820
75 1950
80 2080
100 2600

If your T5 has the more common .74 top gear, then rpm at 100 mph will be about 3100.

85 ZXX

iTrader: (1)

Great information, thanks for sharing that! My T-5 was removed from a 89 IROC and I'm not sure what the tranny code is right now. In 89, I bought a new Mustang 5.0-5 spd and it would turn 2400 RPM's @100 MPH. It was rated @ 152 MPH top speed. Not bad off the showroom floor for $15,200. I really wanted the TA back then, but none were available in my area.

Dante93GTZ

iTrader: (5)

Is the process any different with the rear out of the car? I think my pass side axle seal is leaking - I'm assuming on a 10bolt that means the axle is in need of replacement as well. Where can I get one? The auto parts stores don't seem to have 'em.

Is there a diff between an axle shaft from a rear disc and rear drum axle?

JamesC

iTrader: (5)

Yes. Check below for more info:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

SR-71

Don't assume anything. Pull the axles out and inspect them, lest you buy something you don't need. I just went through the rear axle on mine. It had about 250,000 miles on it and had never been opened up. Heck, I bet it still had the original oil in it.

Anyway, one of my axle seals had a small leak, and the pinion seal was leaking. There was no detectable wear on the axles or the pinion. I slid the axles in without the seals so I could check for side-play in the bearings (still within new specs), then I put it all back together with new seals.

There are lots of places to buy axle shafts. Summit Racing and Jeg's both come to mind right away, though I don't know if you can't get a better price somewhere else.

Replacement Moser axles for my car's 10-bolt, $245 for a pair (sold only in pairs).
Apparently they are the same for either disc or drum brakes.
http://www.summitracing.com/parts/MSR-A102604/

Dante93GTZ

iTrader: (5)

Just got my bearings/seals swapped out a few minutes ago - I've got a 3.23:1 posi/disc rear that's going in my 91 Z28 so I figured it'd be best to do this stuff BEFORE it goes in the car.

The process was actually VERY easy - Nothing complicated. I rented the tools from AutoZone and everything went smooth. The axles felt totally smooth, no grooving at all!

Thanks for the info & pics! Very helpful!

Adversity11

Which Bolt are you guys talking about? I need to change the rear axle bearings and seal on my 89 formy and am new to DIY. Picture of the bolt please? Also is it a good idea to put grease on the bearing? I heard from a few people that putting bearing grease on the bearings will help them last longer and make them quieter.

Edit** I think I know what bolt you are talking about now. Is it the one that goes through the hole on the pinion shaft?
And when I bought my bearings it came with a smaller round metal washer looking piece what is that for?

Frank Telli

question: i have a 92 RS 25th Anniversary 305 TBI and i need need rearend gears because when its making a rubbing sound. My question is can i use 3.42 gears for my car?

JamesC

iTrader: (5)

Welcome to TGO, Frank.

As you can imagine there aren't many questions that haven't been asked and answered on-site, so a search will generally turn up the info you seek. The answer to your question is yes, but there are some things you need to know. I suggest that you peruse the following link which, I think, will answer most of your questions.

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

sandman92084

A helpful hint that I learned earlier today if it is a fourth gen rear from a car with traction control the wheel speed sensors need to be removed from the brake backing plates to be able to push the axles in far enough for the c-clips to come out

hilltop530

you see this is why I love owning a Chevy. People will take the time out of their day to write up a good step by step to help others out.

bravo sir.

NW Task Force

Need some real help here........I have a 1982 Trans Am rear end with disc brakes, posi, 3:23 ratio (all stock). The passenger side inside wheel started getting sprayed by gear lube while driving. The lube basically flung out of the slotted parts of the brake rotor. I decided to follow your axle bearing/seal replacement write up exactly. The job was straight forward and I felt confident that this was going to work well. I bought the "one-piece" units designed for worn axle shafts from Napa. I completed the test drive and discovered the same passenger side axle seal leaking again!!!! I reused the both original axle shafts. The problem side axle shaft showed wear similar to yours in Post 6 with some small pitting. I can only guess that this axle shaft will not seal period? If I do find another better condition axle, can I continue to use the replaced/new seal I just installed? Or maybe I have to start over with a new seal again? Bummer that I spent hours trying to seal this axle up with no success.........

SR-71

If the axle seal has been leaking, and the axle looks anything like those in post 6 or has any kind of wear where the seal runs, I replace the axle.

Nobody knows better than me how much it can hurt the budget. My budget it TIGHT. But if you're planning to keep the car for any length of time (mine is a permanent family member), new axles are a great investment. "Only" $260 from Summit or Jegs for a pair of Mosers.

With a good axle, regular seals cost about 5 bucks. Cheap insurance. Don't re-use the ones you just installed, just in case. I would rather not be pulling it apart a third time.

NW Task Force

I just purchased a good/used axle shaft from the same company. The axle shaft sealing area was much better than my existing one. I swapped in the axle shaft and did everything I did as before. Filled up the diff and took it for a test drive............... stupid diff fluid leaking out of the wheel end again!!! What gives? The axle sealing surface was clean/pitting free/no grooves/and the bearing/seal was new and installed exactly as directed in this thread. The bearing/seal that I used was one from Napa Auto Parts. It is a one piece unit designed for grooved axle shafts and actually moves the sealing surface to a new part on the shaft. Is this where I went wrong? Maybe stick with OEM two piece seal & bearing? I am seriously running out of options/ideas on what is causing it to not seal. The other wheel end received the same treatment on the one piece seal...........zero problems. Weird! This would be the 2nd attempt at fixing the leak.