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Rookie does Rear Differential Rebuild

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53K views 39 replies 18 participants last post by  Mmusicman  
#1 ·
As threatened, I did rebuild of my differential. Please don't flame me for anything that I am sharing. I am simply being honest about what I did and how I did it. I am not advocating that anyone should do what I did. I am not a mechanic, just someone who wanted to give it a shot. Maybe someone else can learn from my experience as a rookie. So far, very happy with the results. Van is MUCH quieter than I can remember it ever being and even seems to accelerate quicker.

As far as parts, here is the run down: Master rebuild kit from Rockauto.com, $78 included pinion bearing cups and cones, pinion seal, carrier bearings, pinion nut, gear marking paint and a brush and RTV gasket maker. I chose to order a new gasket for a few dollars. I bought a new diff shaft locking bolt from Goodwrench for $3.50. Bought new rear wheel bearings and seals, synthetic gear oil and limited slip additive from autozone for a little over $100. I bought some tools from Harbor Freight. A mid-grade slide hammer set, a good quality seal/bearing driver kit and some cheap gear pullers. Between parts and tools, I probably laid out $255 for the job. NOTES: I found out that a shim kit was really not optional and I should have bought one in advance. The seal driver kit was adequate for the job and HUGELY important. Also, I would either invest in a better slide hammer to keep or borrow an industrial grade one.
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First, I jacked up the rig, lost the donut so I had room to work, removed wheels and brake drums. I decided to do the wheel bearings first. Also I decided to do the job without removing the rear-end. This was a choice that my back and neck are still paying for.
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The original problem is that I was getting a roaring noise that never changes pitch. I was hoping that it was merely a bearing problem and not that my gears were toast. On inspection, I was quite pleased with the condition of the ring and pinion gears. Lots of steel shavings on the magnet though.
To be continued....
 
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#2 ·
Good write up ! , thats the way i would of done it too , rebuild instead of buying a junk yard one with alot of miles , plus in a way its kinda fun building it up and learning how .
It would be nice if you could give a full list of tools needed and all the parts you had to use and where you got them .
 
#3 ·
It would be nice if you could give a full list of tools needed and all the parts you had to use and where you got them .
Or maybe in hindsight, a list of what I SHOULD have bought.
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I should say at this point that I matchmarked everything that I could think of to aid in the re-assembly. That and the pictures helped alot. I took about 100 pictures of mundane things just as a reference in case I got into trouble. I was working alone and needed all the help I could get.
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I had seen how this all fits together in youtube videos and diagrams, but it still wasn't very clear to me. The lock bolt secures the shaft (round shaft to the left of the bolt) It runs through the differential and spider gears and locks the axle clips into detents.
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With shaft removed, rotate axle and spider gears rotate for removal... I finally know why they are called spider gears, they resemble the motion of a spider when they are moving.
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Push the axle in and the clip can be removed. I figured that it would be difficult, but it practically falls apart.
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The axles slide right out with the c-clip removed...
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I inspected the axles and they looked good. No grooves where they ride on the wheel bearings. Mind you, I didn't use a micrometer, but they looked and felt good. Axles are around $100 and I was prepared to buy them if needed. I understand that there are spacers to relocate the bearing to a different location on the axle shaft. Luckily didn't have to do either. Continued.....
 
#4 ·
Here is a peek at the bearing and seal from the passenger side. I would call this normal wear. Remember, this van has NEVER had differential/Rear axle service ever. Not even a fluid change in 224k miles. I know- I should be shot. I change my engine oil religiously.
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I pried the seals out with a claw. Damaged them of course, but had replacements on hand so I didn't care.
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Time to remove the bearing... Set-up slide hammer with 3 claws... Set in place and then...
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proceed to beat the crud out of the slide. I might add at this point that the motion of using a slide hammer is NOT foreign to me. Afterall, I have been married 24 years and I have forearms like freakin' Popeye. This was a 5lb slide hammer that I was using and I beat the tar out of the bearing until I was blue in the face. Sorry, no PB Blaster for the win. More like PB Blaster takes a close second and the propane torch for the win. Even after torching the bearing red-hot, I still almost had a coronary beating these things out. Holy SHIZZLE!
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I cleaned and lubed the axle tube and the new bearing. The Harbor Freight bearing/seal driver kit was and exceptional product for the money and completely necessary. I got to use it for the first time to drive in the bearing and seal. I knew when the bearing was completely seated because it made a different sound when I hammered the driver.
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The driver's side was a little bit easier because I torched the bearing before I tired myself out. The wear on the old bearing was similar. I lubed the seals with gear oil. Overall, wheel bearings should be fairly easy to do. I simply would use a more industrial slide hammer and would not hesitate to torch the bearings first.

I'm posting in small segments because my internet tends to go down and I don't want to lose my work. Moderators, please let me know if this is overposting. Continued...
 
#7 ·
I wanted to go very slowly dissasembling the differential. (since it was all new to me) Lots of pictures and matchmarks. Before taking anything apart, I turned the pinion yoke and carrier to have a feel for the preload. Carrier and pinion together turned fairly easy but spin was arrested by friction very soon after releasing pressure. I could hear the sound of grinding sand when it turned. I also noted the sound of the backlash. (the "tick" sound where the ring gear and pinion gear make contact) Turning the pinion yoke back and fourth- tick, tick, tick. I removed the bolts that hold the collars on the carrier. BTW, it should be a law to use synthetic gear oil because the petrolem stuff really stinks!
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in the picture above, to the left of the left bearing, you can see a shim. There is a shim on each side and these space the ring gear to the pinion gear. The lack of a shim kit caused me some grief and panic later on. The carrier and shims came out very easily, just the lightest tug and it was out. I immediately marked the shims left and right.
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withe the carrier in my hands, I could finally inspect the carrier bearings. The right side bearings (cup and cone) were pretty bad. The left side bearings were BEAT! huge, deep pits in the bearing rollers. Absolutely trashed. This I am sure was the main source of my roaring noise.
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Note the markings on the ring gear that everyone refers to. With the carrier out, I could check the preload on the pinion and see how sloppy it was. I tried to shake the yoke and see if it moved from side to side. Didn't seem too sloppy, just a tiny bit of movement. When I tried to spin the propeller shaft, it turned about twice before the spin was arrested. It sounded like a coffee grinder though.
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Continued... have to take my daughter to school.
 
#8 ·
To remove the carrier bearings, I placed a gear puller over the bearing with a seal driver plate for support. I tried this method using only the force of the puller, PB Blaster and tapping, but the sucka wouldn't release. (Broke the puller jaw though- sounded like a shotgun) I fired up the torch again and heated the bearing while using previous method and it popped loose after a few minutes. Heat, tap, tighten, heat, tap, tighten.
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It wasn't that hard to pull the bearings, just can't be "torch shy". At least the cups didn't have to be beaten for the carriers. To seat the new bearings, I used the bearing race from the old bearing and the seal driver.
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The carrier is ready to go and now for the pinion. This is where you are supposed to install a special tool (Pinion holding tool) on the pinion yoke. It stops the pinion from turning while you loosten the pinion nut. I used a "big-a$$ed" pipe wrench to hold the yoke and it worked out great. Needed a cheater bar for my ratchet and the nut broke loose. The pinion nut is 1-1/4" and I had to borrow a socket from the in-law.
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Loostened nut completely and re-threaded it a few turns. Used nut to protect propeller shaft from hammer damage. I hit nut with hammer and drove the pinion out. (new pinion nut was in kit)
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The seal and outer pinion bearing was simply packed with dirt. No idea how the bearings survived.
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Both inner and outer bearing cups were in very bad shape. No surprise judging by the mudpack in the bearings.
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Pulled pinion seal with brute force, no need to save it.
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Continued...
 
#9 ·
I applaud you for your effort on this rebuild.

Now something that you have to realize is that you can NOT measure the amount of backlash based on the old parts being removed. That is not uniform from used and worn bearings to new bearings. There are several very critical measurements you need to make to properly rebuild that rearend.

Here is a couple helpful links:

http://www.chevyhiperformance.com/techarticles/148_0207_10_bolt_rearend_gear_install/index.html

http://selectric.org/manuals/rearend/yukoninstman.pdf

If the preloads are not right, unfortunately the rearend will not last long.
 
#11 ·
Now something that you have to realize is that you can NOT measure the amount of backlash based on the old parts being removed. That is not uniform from used and worn bearings to new bearings. There are several very critical measurements you need to make to properly rebuild that rearend.

Here is a couple helpful links:
Yes. I know. On September 13th, I posted:
Any pictures, videos, links, helpful advice would be appreciated.
You told me to skip the rebuild and replace with a junker. Your advice is appreciated, but weeks late. I did my homework before delving into this project. The chevyhiperformance.com link was one of the references that I used. There are several youtube videos that are helpful in setting pinion depth, backlash and preload on carrier and pinion. Everyone seems to discourage the effort because if not done properly it will not last. My emphasis was in doing the set-up correctly so that it would last.

Removing the front and rear pinion bearing cups was the hardest part of this project for me. My decision not to remove the rear-end made this job much tougher. I suppose that you can use a pulling method to remove the cups, but I chose to drive the cups out. There is a cutout at the top and bottom in the steel casing that the cups are seated in. (reference a few pictures up) I used my floor-jack handle to push against the cups and drove them out with a 10-lb sledge hammer. (Grueling work) And, yes, had to torch them red-hot.

The rear pinion bearing was surprisingly easy. I just torched it and pried between the bearing and gear with two chisels. Popped right off. (finally something easy)
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Seating the new rear pinion bearing was kinda tricky because I didn't want to damage the gear or shaft. I used the old bearing to tap the new bearing into place. Once seated fairly good, I tapped the bearing race with a punch and hammer. I had to make sure that the pinion bearing was pressed to the max. Pinion gear depth can be changed by using a different shim washer between the gear and bearing. I used the original shim.
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At this point, it was 11 PM on Saturday night and I called it quits. I had worked on this project for 10 hours. Professional mechanics will quote only around 5 hours labor for the entire job which I was only about 3/4 done with. Continued...
 
#12 ·
Infidel, What a write up, What a job. I'm glad you went this route. Junk Yard replacement has its place, but in my opinion, not here. This one will go into my record books as I'm probably not far behind. Once again thanks for stepping up. Jim
 
#13 ·
Junk Yard replacement has its place, but in my opinion, not here.
Thanks Astroturf, I think the rebuild was the right decision. I often make bad decisions... and now, back to the kitchen to cook bacon with my shirt off... :D
 
#15 ·
Woke up Sunday morning ready to get this knocked out.
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First, pounded in the rear bearing cup. Was not too hard. (found out later that I did not have it seated all the way. Used a cheater bar on the seal driver and pounded it with a 10-lb sledge- That'll shut her up!)
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#16 ·
At this point, all the brute work was done and now, just had to dial this bad-boy in. At this point, I kinda stopped taking pictures. I first did a test fit of the pinion install without the crush sleeve to get an idea of the pinion preload. I used the "big-@ssed" pipewrench to hold the pinion yoke and tightened down on the nut. I was very happy with the test fit. The idea of pre-load is that the bearings are compressed to the point that the "spin" of the pinion is arrested by friction at a certain point. You put a torque wrench on the pinion nut and turn it reading the torque. I was going to set pre-load to 15-17 inch pounds but it felt too loose and I eventually took it closer to 20 inch pounds. 20 inch pounds arrests the spin of the pinion after one full revolution.
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I installed the carrier with bearings and shims. Extremely tight fit, had to hammer the shims in. Began to question if I had the carrier bearings completely seated. Removed carrier and pounded the bearings onto the housing. Turns out that I did that job fine. I ended up fitting and re-fitting many times. As mentioned earlier, the rear pinion cup was not completely seated and I ended up wasting a lot of time before I realized what the issue was. The pinion gear would actually contact the differential carrier as it turned. After taking care of that problem, things went much smoother. My father in-law came over to help me dial this all in and we fussed with the adjustments for a few hours. Set backlash with dial indicator and magnetic mount. The idea behind the shims is that you install the carrier with bearings and cups. Measure the void between the bearing cup and casing. This gives you the total shim thickness desired. Then, you split the total shim thickness so that the ring gear will make the proper contact with the pinion gear. I was counting on using the original shims. I decided that I wanted a shim kit but could not find one on a Sunday afternoon. Checked Oreily, Autozone and Advance. Was told that best source for a shim kit would be Napa and dealership. In order to get the backlash and pre-load on the carrier close enough, I ended up grinding and belt-sanding one of the shims. (cheezy but worked great)
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Below are some links to the "proper" procedure.
http://www.richmondgear.com/01instructions.html
http://www.highperformancepontiac.com/t ... index.html

Finally put it all together with my new crush sleeve in pinion and used an impact wrench to get my preload right. I decided to use the impact because it is really tough compressing the crush sleeve. Did one more check of total preload and tooth mesh. The pattern looked pretty good and time was running out for me. I put the whole thing back together and filled with limited slip additive and synthetic gear oil.

On the first test-drive, I was scared to death. I'm confident, but naturally skeptical as well. I drove it only a few miles and dropped off my father in law who was very tired of helping me. Ran the van forward, reverse, coast, accelleration and everything sounded good. I could not believe how quiet the van was. Went back and re-checked the driveshaft bolts and wheel lugnuts. Everything seemed fine, but I was very nervous about taking the van 270 miles to Myrtle Beach. Didn't have a choice though, had to get back for work. I have driven the van about 600 miles since the rebuild and still holding up well. I've gotten over the nervousness and I really get on the gas now too. Maybe my experience is beginners luck (even a broken clock is right twice a day). I would encourage anyone who has the tools and the time to attempt this if this. Also, would discourage anyone from trying this unless they really want to do it. I probably only saved $250-350 by doing it myself. The truth is that I am glad I did it.

Sorry about the lack of pictures of the dial-in. My father in law was nice enough to help and I didn't have much time left. (that, and the fact that he thought I was freaky for taking pictures) My plan is to crack it open one more time when I am at my house next time. I will have a real shim kit with me. I will inspect for wear and replace the modified shim with the proper part. I'll make sure to take more pictures at that time. I'm considering sandblasting and painting it so that it looks nice and slows down the rusting. The nice thing is that the bearings are all replaced and I can go back with posi-traction or change the gear ratio in the future without too much trouble.
 
#17 ·
Good job.

The only reason I suggested to you to just get another one from a pick and pull is because I do not believe a 10 bolt is worth the time and money of rebuilding it. They are a cheap rearend that GM used. The housings even warp after years of usage. Regardless of what you do, they will wear again and just fall apart. Its really ashame that you didn't get pictures of the tooth patterns for the backlash, that by far is the most important measurement you can find.
 
#20 ·
astro355 said:
Good job.
Its really ashame that you didn't get pictures of the tooth patterns for the backlash, that by far is the most important measurement you can find.
Why is it a shame that he did'nt post pictures of his tooth patterns for the backlash ? Dont you trust that he researched it out and adjusted his backlash correctly ?
Infidel , I think you did a outstanding job with this write up !
Here's a picture for referance for people who use this writeup
 

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#21 ·
webcat said:
Why is it a shame that he did'nt post pictures of his tooth patterns for the backlash ? Dont you trust that he researched it out and adjusted his backlash correctly ?
Infidel , I think you did a outstanding job with this write up !
Here's a picture for referance for people who use this writeup
No, seeing the real thing is far better than looking at a drawing. That's why its a shame. For anyone else that is considering this rebuild, that is the most important picture that could have been taken. I can't stress that enough.

It doesn't matter if I believe he did the research or did it correctly. That's not the point. :confused:
 
#22 ·
Infidel.
Thank you for sharing allthis great info and your pictures and story.

I wondered what this job might be like, and now I have a much better idea.
and several links to even more info.
I think I might giver a go especially if I can find a suitable 10 bolt 8.5 inch. ;)
I've got several astro axles here. I guess a front axle would be the same basic procedure.
Thanks for the encouragement.
I truely appreciate it.
 
#25 ·
nielswheels said:
I am in need of a rebuild on my Astro rear end...looks like hard work...great write up. If I wanted to put a "better" rear axle in.....what would be a stronger one that would bolt right up??? Thanks
read through.....I think it was Mr. Roboto found that older Furd E series have a similar offset, with a 9" R&P, that work in our vans with minimal mods. Not a direct bolt in..there isn't one, but it has a similar offset.
 
#26 ·
rev_les said:
nielswheels said:
I am in need of a rebuild on my Astro rear end...looks like hard work...great write up. If I wanted to put a "better" rear axle in.....what would be a stronger one that would bolt right up??? Thanks
read through.....I think it was Mr. Roboto found that older Furd E series have a similar offset, with a 9" R&P, that work in our vans with minimal mods. Not a direct bolt in..there isn't one, but it has a similar offset.
how much earlier? i missed that thread