GM 10 Bolt rear End

[Turbovert01]

So the GM 7.5 inch 10 bolt gets a really bad rap from people for apparently breaking on stock manual fbodys, while others say they run a spray and a 3500 stall and it still holds up fine. Here are some of the factors I have read affect its longevity, I may be forgetting some.


Auto vs Manual:

An automatic car will put less strain than a manual car, as it will not “shock” the gears like a manual car.


Street vs Sticky Tires:

Generally speaking Street tires will spin, sticky should hook, sticky tires will place more a “shock’ on the rear increasing the likelihood of failure.


Street vs Strip:

You will never get the same traction on the street that you can on a track. Track racing will give harder launches and shock the rear more = more likelihood of failure.


Turbo vs Naturally Aspirated

Some forums say that because turbo power usually comes on later in the RPMS that a N/A engine the rear is under less stressful launches in a turbo car. Of course this may change depending on stall size.


Stock vs Stalled Transmission

A stalled car will launch harder than a stock limited car, resulting in more strain and shocking of the rear. This effect could be be intensified if this stall brings you into your turbo powerband. (I am not sure how accurate this actually is but people have said this)


Stock vs Upgraded Suspension:

A stiffer, upgraded suspension will cause less wheel hop, meaning less of a shocking force = less chance of failure.


Rear Gear Ratio:

I’ve read conflicting opinions.


Now given this I have a two scenarios I need some opinions on whether you think the rear will survive as a STREET car either as stock or modified:

1. Stock 7.5 inch fbody 10 bolt
2. Modified (c clip eliminators, girdle, eaton posi unit, axles, yukon ring and pinion etc)

Scenario #1: A4, 3.8 turbo, 3000 stall converter, stiff suspension (TA, SFC, LCA), 3.42 rear gears, Street tires, Street application only.


Scenario #2 A4, 3.8 turbo, 3000 stall converter, stiff suspension (TA, SFC, LCA), 3.42 rear gears, M/T Drag Radials, Street application only.


For both of these will the stock or modified version survive? I am hopeful that my set ups factors may allow me to run drag radials on the street with a modified 10 bolt. Please only respond if you have experience with this and not what you have read online as the information there is conflicting.


Thanks!

*update* left off it will be about 400 RWHP and 400 lbft of torque

[LETZRIDE]

Now given this I have a two scenarios I need some opinions on whether you think the rear will survive as a STREET car either as stock or modified:

1. Stock 7.5 inch fbody 10 bolt
2. Modified (c clip eliminators, girdle, eaton posi unit, axles, yukon ring and pinion etc)

Scenario #1: A4, 3.8 turbo, 3000 stall converter, stiff suspension (TA, SFC, LCA), 3.42 rear gears, Street tires, Street application only.


Scenario #2 A4, 3.8 turbo, 3000 stall converter, stiff suspension (TA, SFC, LCA), 3.42 rear gears, M/T Drag Radials, Street application only.


For both of these will the stock or modified version survive? I am hopeful that my set ups factors may allow me to run drag radials on the street with a modified 10 bolt. Please only respond if you have experience with this and not what you have read online as the information there is conflicting.


Thanks!

*update* left off it will be about 400 RWHP and 400 lbft of torque

I'll start with the famous - "we're not God and therefore we cannot predict whether or not your rear end will hold up" - else I would predict the lottery numbers and be rich...and that is my stand up comedy for the day.

You have a lot of good information - an automatic is certainly going to lessen the impact on the 10 bolt versus a manual. However, once you introduce things like a trans-brake and stall converters it is a whole different ball game. Stall converters and how hard they impact your rear end I would argue would have more to do with the STR or torque multiplier within the stall - see post #2 of Stall Converter FAQ's here if you haven't come across that yet in your readings. The higher that number the more your torque is going to be multiplied the harder you are going to hit off the line.

Also remember that just because you have a 4000 stall for instance doesn't mean you can foot-brake and leave the line at 4000rpm. My YankSS3600 in my LS1 won't hold past 3000rpm before it pushes through my brakes.

The type of tires you use can also soften the initial blow the rear end. Wrinkle wall style slicks absorb some of the impact versus a hard stiff walled drag radial.

That being said, nothing is "safe" in the rear end when adding power. Although I will say I expect scenario 1 to last far longer than scenario #2.

To give you some food for thought I went through 2 10 bolts with my 3.8 stalled auto. I think it was when I was cam only for both failures not my bigger heads/cam setup I went to later. My two setups were as follows:

Setup 1

3.90 gears with a new zexel torsen posi. The car was cam only with a 3200 stall converter from TCI - I think that setup lasted about 2 years before I blew it to pieces at the track.

Setup 2

3.90 gears with an eaton posi, 3200 stall still cam only. This setup lasted just under 1 year and I lost my tire out the back of the camaro getting off the highway.

I thought the zexel being worm gear driven was maybe just too weak for a street/strip application even though I only used MT ET streets when at the track. I figured since the Eaton unit had forged internals it should hold up to my 3.8. It was just as fragile. In both cases the ring gear was totally fine. I believe you will shatter an axle or a posi unit before a ring/pinion in these cars - but that is my personal opinion given the axles are lowly 28 spline shafts and the posi's are just weak.

After the second incident in less than a 1 year time frame, I jumped into gear to find a cheap alternative that was still beefy - that put me over the ford 8.8 rear end. Lighter than the chevy 12 and Ford 9 but pretty much just as strong. My only mistake was initially going to 4.10 gears, I revved too damn high on the highway that it annoyed me lol. Yes 3.90 to 4.10 made just that much of a minute difference .

Pics of my Ford 8.8 swap and setup that went into my 3.8 can be found here: Ford 8.8 swap pictures into camaro