Pontiac G8 Forum banner
1 - 20 of 30 Posts

·
Registered
Joined
·
1,032 Posts
Discussion Starter · #1 ·
I have another thread going where I was trying to figure out a clunk from the rear. Long story short, the spider gears in the differential center section are FUBAR. I also discovered one of the axle boots had split. Finally I had decided to upgrade the rear cradle and differential bushings as long as I had it all apart. I'm starting this thread to document the repair of all.

Starting off, the rear cradle was dropped an the differential removed. The differential was split for inspection of the internals.
Gas Bicycle part Machine Metal Auto part


I've been thinking about the various options on what to do here and have not made up my mind yet. Option 1 is some form of rebuilding the original differential. This is complicated by the fact that some parts are no longer available. This is further complicated because the differential itself is an oddball. Option 2 is swapping in a Camaro rear. This hopefully would solve most of the finding parts problem in option 1. Though I would need to source a rear and once I got it I would have to rebuild it because it's history would be unknown to me. Option 3 is to buy an expensive custom rear. But I don't take the car to the track so not only is it expensive but it is way overkill for me. I will stick to options 1 and 2.

I decided to do some more teardown of the differential to assess how bad the damage is. I removed the rubber axle seals.
Gear Bicycle part Automotive tire Gas Machine


There is a snap ring that needs to be removed. I have a couple of snap ring pliers but this snap ring was too big for them. But I managed to get it out. After that I had to tap the other side with a dead blow hammer to loosen things up and the spacers and the center section came out.
Automotive tire Wheel Rim Automotive wheel system Gas


I spun the center section bearings by hand and they felt 'lumpy' for lack of a better word. I spun the pinion by hand and it was way worse. So all the differential bearings are shot too. The ring and pinion look OK, but I need to clean them to inspect them better. If those guys are shot then I'm pretty much only left with option 2.
 

·
Pontiac Crazy
Joined
·
662 Posts
I agree with Hot Rod out of experience. Earlier this year I broke a CV shaft while visiting family up in Iowa. The nearest replacement Camaro shaft was 2 hours away in Des Moines. If I had needed a G8 one, I have no doubt that I would have been stuck for days waiting for one to be shipped in. Instead, I had the car moving again later that same night.

Get whatever Camaro diff you can pick up for the cheapest then swap in a gear set with your desired ratio and an Eaton TrueTrac with billet main caps.
 
  • Like
Reactions: T-Type and Hot Rod

·
Registered
Joined
·
1,032 Posts
Discussion Starter · #4 ·
I agree with Hot Rod out of experience. Earlier this year I broke a CV shaft while visiting family up in Iowa. The nearest replacement Camaro shaft was 2 hours away in Des Moines. If I had needed a G8 one, I have no doubt that I would have been stuck for days waiting for one to be shipped in. Instead, I had the car moving again later that same night.
If the Camaro differential is a direct bolt in, wouldn't the half shafts be the same G8 vs Camaro?
 

·
Pontiac Crazy
Joined
·
662 Posts
If the Camaro differential is a direct bolt in, wouldn't the half shafts be the same G8 vs Camaro?
Yes, I have a full Camaro suspension swap. I was using it as an example for parts availability. You would still use G8 half shafts in your case of just swapping the diff. Though, you do already have the entire cradle dropped.... just saying
 

·
Registered
Joined
·
1,032 Posts
Discussion Starter · #6 ·
Ah, OK. So out of curiosity, what would be the benefit of swapping out the cradle? Just better parts availability?

As to the differential I'd be looking for one out of a 2010 - 2015 Camaro SS, correct?
 

·
Pontiac Crazy
Joined
·
662 Posts
Better parts availability, slightly narrower hub to hub (for those trying to squeeze every last bit of rubber underneath), lighter knuckles (aluminum vs cast). You also get more aftermarket options for certain things like the cradle bushings. Camaro Cradle Swap PICS

Yes, 10-15 SS. I think gear ratios are auto 3.27, manual 3.45, and 1LE 3.91. Do not get a ZL1, it's different.
 

·
Registered
Joined
·
1,032 Posts
Discussion Starter · #8 ·
So I've been researching this this Camaro differential swap. I understand I need to get something out of a 2010 - 2015 Camaro SS. The bolt in options are 3.27, 3.45 and 3.91 as mentioned.

Problems I see are as the ratio goes up, so does the price big time. Another issue is I have 3.70 gear (manual car), none of those is an exact match. My preference is 3.70 though I do understand the closest two wouldn't be hugely different. I'm thinking I can get a prettty cheap 2.92 and rebuild it with a 3.70 gear or as closd as i could get. But I don't know if that is possible without some extra modification. I'm looking for some advice.

Also can i expand my search to Chevy SS and the PPV? Or are those the next gen and they wont fit perfect?
 

·
Registered
Joined
·
2,948 Posts
Be aware, different diff manufacturers, ring/pinions are not interchangeable. G8 is a ZF, Camaro is a AAM (American Axle).
 

·
Registered
Joined
·
5,226 Posts
Size difference too. 8.2” vs 8.6” from the Camaro.
 

·
Pontiac Crazy
Joined
·
662 Posts
You mentioned you would rebuild one with an unknown history anyways. Just grab the cheapest one from a Camaro you can find then change the ring and pinion to your desired gear ratio. You can get 3.73 for the Camaro diff.
 

·
Registered
Joined
·
1,007 Posts
Reading between the lines , because I have never opened a G8 diff,
The cheapest repair would be if your 3.70 gearset passes visual and a proper crack test by a real lab.
Buy a used G8 diff and put in the 3.70s knowing you will need to do proper set up.
Thing is, you would be back to where you were and " ya already broke that "
Think I would be on the Camaro diff band wagon here with the closest thing you could get to your 3.70
3.70 /3.91 = .946 , not huge.
 

·
Registered
Joined
·
1,032 Posts
Discussion Starter · #13 ·
Here's my current dilemma. I am not opposed to the Camaro differential but looking around they are expensive (IMHO) for used units. The 3.27 is around $700. The 3.45 is around $ 1400. I found a 3.91 and the asking price is $1800 and the listed mileage is 91k. Pricey and no guarantee they are still in good condition (remember these are pulled out of the more powerful Camaros and not Grandma's Buick). So yes, I am still entertaining just rebuilding my original differential. Though the center section would be aftermarket and hopefully much stronger. But replacement parts are not easy to find.

Speaking of hard to find parts I am also struggling with the passenger side axle. It has a split boot IB and the OB looks bad. I thought I had found replacement boots but it turned out they were not correct for my car. If I can't find a solution to the axle issue, I may be looking at swapping over to a Camaro rear cradle assembly. That has it's own issues. Yes, it bolts right in but from what I've seen it's not that straight forward. It's not clear to me if all the brake connections are the same. Is the bolt pattern for the wheels the same? An of course there is the does it need to be repaired somehow issue.
 

·
Premium Member
Joined
·
10,473 Posts
...I am not opposed to the Camaro differential but looking around they are expensive (IMHO) for used units. The 3.27 is around $700...
Currently, a
Low mileage 3.27 LSD Camaro differential
is available in the parts for sale section. Perchance the seller know its history. :unsure:
 

·
Pontiac Crazy
Joined
·
662 Posts
If I can't find a solution to the axle issue, I may be looking at swapping over to a Camaro rear cradle assembly. That has it's own issues. Yes, it bolts right in but from what I've seen it's not that straight forward. It's not clear to me if all the brake connections are the same. Is the bolt pattern for the wheels the same? An of course there is the does it need to be repaired somehow issue.
Brake connections are different flarings. Camaro uses inverted 45 but the G8 has a bubble flare. You can use your G8 brake lines, they just won't bolt to the control arm tab. Just zip tie em in place.

Yes, the wheel bolt pattern is exactly the same. Many people have put Camaro wheels on otherwise stock G8s.

I'm planning on posting a complete, updated thread regarding the G8 to Camaro suspension swap (front and rear). I'm just waiting on my new coilovers to be built and a custom metal insert that I need.
 

·
Pontiac Crazy
Joined
·
662 Posts
Can you point me to your existing thread on your swap?
It's the thread I linked before: Camaro Cradle Swap PICS

Not mine, I've just contributed. There's a separate thread for the front, which is one of the reasons I want to make an updated, unified post.
 

·
Pontiac Crazy
Joined
·
662 Posts
Sorry, I forgot you posted that earlier. So clearing the spare tire well is an issue I see. Also the one electrical connector will need to be modified.
You can reuse the G8 sway bar and the tire well isn't an issue. I did that with someone else's GXP that I did the swap on. Electrical connector is an easy cut and splice, 4 wires.
 
  • Like
Reactions: T-Type
1 - 20 of 30 Posts
Top