IDK how my ring gear broke a tooth but need rebuild advice (yes I read every thread regarding rear diff rebuilding. My issue is different)

87WE4!!

New Member
#1
Hi everyone,
I hope all of my club brothers and sisters are doing well . I have sone unique questions. I did do a search but I only some of my concerns were resolved. So I had to start a new thread. Let me start by saying that I strongly know my way around these cars and am very up to date on the technology but I am far from en expert and most of y’all probably forgot more then I’ll ever know about our cars. I got major love and respect for you guys because y’all read our problems and offer solutions. This is the way the whole world should operate. That being said I come to y’all because I have an issue with my rear G80 diff. Let me start by saying that I’ve either assisted in or completely rebuilt both engines and GM transmissions.
But I’ve never done more then remove clean and paint the exterior, and change the oil in a rear end.
Ok so for those who haven’t had a chance to read my intro I APOLOGIZE FOR THE LONG STORY. BUT ITS REVELANT. I’ve owned my WE4 Regal since I was 17 and bought it brand new a few days after my 17th birthday after making a deal with my mom she lent me the cash to buy my dream car which was a Grand National (long story I was a wild teen who was very disrespectful especially to my mom. I had no dad so I had a chip on my shoulder and was expelled from my High school and transferred to a HS on the other side of Brooklyn my mom offered me the loan if I agreed to finish my last 4 months of high school. And if I paid her back in monthly payments no interest or liens. Unfortunately at the time every Grand National was sold out and we were told GM wasn’t making them anymore. The WE4 fell in my lap because someone per ordered it and couldn’t complete the sale so they called us back 3 days later and I was like “close enough for me”
In 1997 my mom passed away unexpectedly at age 56 from a heart attack. Now the reason why I had to write that whole above paragraph was because that car taught me respect and responsibility and made me turn my life around by going to college and becoming a FDNY firefighter in 1991 till I retired in 2013. This car brought me closer to my mother and made me get help for the anger that I took out on my mother because my dad was taken from me by cancer when I was 9 years old. I paid my mom back every dollar for the car. When she passed I couldn’t even look at that car without tearing up. So my sister let me park it in my sister’s garage on Long Island from 1998 till she retired and sold her house. So she shipped it to me here in Florida. The shipper knew it didn’t run because I never prepped it for a long storage. All I did was park it, removed the battery and gave it to my sister and put a cover over it and never looked at it again. I wasn’t smart enough to drain the gas or anything.
So I have the car about 45 days now and I’m really back into this car again. So I replaced everything fuel related from the tank to the injectors. Long story short I did everything (even changed oil pump gears and packed it to prime the engine). Everything is awesome. Except I decided to change the rear LSD fluid. I noticed a big chunk of the ring gear was broken off laying on the bottom. And it was pretty much bone dry it looked like the fluid caked on to the bottom of the diff and the the spider gears looked like they were glued together it was just full of gunk.
Honestly I think the rear was seized from not moving for 21 years and the mover put the car in neutral and dragged the car out if my sister’s garage and they yanked it with their winch till they broke it loose. When the car came to me it rolled perfectly but wouldn’t stop lol the brake pedal was seized and the powermaster was short and I had to replace that last week.
This car is bone stock and I put every one of the 59k miles on the car. And I never beat on this car since I got it. So I definitely didn’t break it. But since I’m the original owner and all the numbers match I’m definitely hell bent on fixing that rear.

So I was lucky enough to purchase a NOS set of clutch and pressure plates and a preload spring. And so far I removed the entire carrier and marked what caps and shins go where. (I haven’t touched the pinion yet). The old clutches are so stuck and seized together that I had to use a flathead screwdriver to separate them. Everything else looks great. The spider greas look fine they cleaned up nicely. The only issues are the ring gear. And I can’t see the pinion gear well enough to rule out anything cracked or missing because the rear is still in the car. Both axels and splines look great nothing leaking from the seals.
Can you guys kinda give me a list of what size carrier bearings I will need as well as shims. And I’m seriously wanting to convert to 4.10-4.11 ring and pinion gears because I love that feeling of being slammed into the seat when I hit the gas. So if you guys could help me in what company I should go with for bearings as well as the gearing that I want. All I bought so far is NOS partial rebuild kit with clutches, plates, and a stock preload S spring. I know I should pay someone to do this and honestly if I still lived in nyc I probably would but I really want to do this myself. And I have nothing but time.

I apologize for my long story. But I had to paint a picture as to why I stopped driving the car and just abandoned it for 21 years.
 

Chuck Leeper

Waay too old!
Staff member
#2
And I’m seriously wanting to convert to 4.10-4.11 ring and pinion gears because I love that feeling of being slammed into the seat when I hit the gas
Just my $.02:
Dismiss that idea...That gear will put the engine rpm's waaay over the top, screw w/ the speedo, etc. Leave the ratio alone.
 

pacecarta

MAGNA
Staff member
#5
pull carrier ,ring and pinion and all bearings and seals ,clean housing and replace all
you can get an eaton style posi , ring and pinion kit and bearing install kit from quickperformance
outer bearings and seals available at most parts stores
 

87WE4!!

New Member
#6
pull carrier ,ring and pinion and all bearings and seals ,clean housing and replace all
you can get an eaton style posi , ring and pinion kit and bearing install kit from quickperformance
outer bearings and seals available at most parts stores
Thank you. This is my first time doing this and I appreciate the list of parts needed. God bless you!
 

87WE4!!

New Member
#9
As for everyone else. Point taken. But does it have to be stock size gears? Keep in mind that I’m taking everything you guys say to heart. I’m absolutely following y’all lead. So if you say that 4.10 gears are out then I’m not going with them. I bought another Grand National about 5 years ago and that’s my “go fast” and mod car. This WE4 holds a lot of sentimental value to me so my upcoming restore plans are to keep it as stock as possible (with the absolute necessities of course Walbro 255, new gas tank, Hotwire, FPR, AEM digital wideband, boost, oil pressure,and water temp gauges,scanmaster, 60lb injectors &tt chip, and Alky kit) but all of those are necessities to keep the car running. Other then those mods I want the car to look as close to stock as possible inside and outside. I only asked about the gearing because I wanted a little more torque when I hit the gas.
2 questions please

1) a friend of mine has an “open” 3.73 rear from a Monte SS that he only wants $100 for because it’s me. Now there’s no way I’m loosing my (G80) but can I use the ring and pinion gears off that rear or do I absolutely have to stick with the stock gearing (understand that I’m only asking because it’s a good deal for the ring and pinion gears I need). Will that size cause me problems as well.

2) I checked around and the only way I could find stock sized gears is at a junk yard and I would have to buy the whole G80 rear for $900 (and that was a negotiation from his original $1300! Asking price). that had more rust and rot on it then I’ve ever seen. It honestly looks like someone left it out in the blazing Florida sun and heavy rain cycle for about 20 years. Plus I wanted to keep my car numbers matching so this is definitely gunna be a build by me.

Those were my 2 main concerns. Now I’m Curious to know
Can I sue a stock sized used ring and pinion from an open rear or is the (G80) gears different for some reason? And if that’s the case can I get away with just changing the ring gesr without pulling out that whole pinion set? It’s not leaking or anything.

If I want to buy a new stock sized replacement ring gear is there anyplace special to purchase it from I don’t care about the money as far as how much everything costs. But I’m hell bent on doing this job myself. It’s no rush.

But I really wanna say thank you to all that read my gear issues and stepped in before I made the mistake of buying the wrong gear. But seriously would 3.73 really be so bad. Just say the word and I’ll stick with stock gears.

Have a blessed day all
 

pacecarta

MAGNA
Staff member
#10
1 a monte is a 7.5 " it wont last under a turbo 3.8
2 3.42 gears are available new
3 stick with the 3.42 ..lots of things will change with a gear a change and not for the better ..on an all out rcecar the 3.42s should still be kept on a lighter faster car ive gone lower to 3.23 when using a th400
 
#11
1 a monte is a 7.5 " it wont last under a turbo 3.8
2 3.42 gears are available new
3 stick with the 3.42 ..lots of things will change with a gear a change and not for the better ..on an all out rcecar the 3.42s should still be kept on a lighter faster car ive gone lower to 3.23 when using a th400
Ok thank you for your help. The stock gearing is the way I will go.
 

Pronto

You're very kind. Some day it will get you killed.
#12
^The only 8.5 rear ends for the TB are on Olds 442s. Monte's are 7.5 and won't last or the gears won't fit in the 8.5.
 

mikestertwo

Well-Known Member
#14
Ok thank you for your help. The stock gearing is the way I will go.
I tried 4.11 gears in my '87 GN years ago. Someone talked me into them. BIG MISTAKE!! The car accelerated like crap! Only had them in for 50 miles and pulled them out. Went back to the 3.42's. Lesson learned! New gears are available from a couple of vendors like Richmond and Yukon
 

dank GN

BlackArts Automotive (661)993-8277
#15
I really hope you have some knowledge of diffs . I did mine myself and prob won’t do another after all the ins and out to get the shim pack right it was not as easy as slapping it in and bolting the cover back on . As suggested you really need to stick with 3:42 . These motors don’t turn high rpms so the 3:42 are the way to go and if u are making some decent power going down a gear set would be the way to go imo like 3:02 or something in that area that is if u are making decent power . Good luck and make sure your shim pack is set correctly so u won’t be one of the guys pulling it out again in a month .
 
#16
Tricky part is crushing the crush sleeve. setting pinion depth also tricky. You can make dummy bearing to help lessen the use of shop press. But some trial and error is to be expected unless you've done a buch of these. Also need a good mesh pattern. Google ring and pinion pattern for pics.