10 bolt upgrades ("big" 8.5", 30 spline, w/big axle shafts and big wheel bearings)

Horntoad said:

This is a 1995 Tahoe 4WD 2DR 5.7L w/3.42 gears. Thanks for reading! (and I've already got 11" duo-servo rear drums I need to install; which is partly why I'm thinking if I've got to pull the axle shafts to install those, what else should I do while I'm at it)

Click to expand...

The 11" rear drums won't bolt on to an axle that came with the 10" drums. The bolt flange on the end of the axle tubes is different. You need the whole rear axle assembly to make that swap.

Supercharged111’s world is real world. So is yours, just different worlds that simultaneously exist. They’re just colliding here.

Caman96 said:

Supercharged111’s world is real world. So is yours, just different worlds that simultaneously exist. They’re just colliding here.

Click to expand...

I should acknowledge that the pull and pay near me has been quite benevolent over the years. And when I paid to have gears set up, well, he's since passed and the garage shut down. But it has set the bar for what I'm willing to pay. If someone quotes me $2600 for it I'll gladly ruin multiple sets to figure it out on my own.

I read somewhere that the 'hoes have the bigger brakes, same as the 2500 6 lug trucks with the 14sf. Dunno....

arrg said:

The 11" rear drums won't bolt on to an axle that came with the 10" drums. The bolt flange on the end of the axle tubes is different. You need the whole rear axle assembly to make that swap.

Click to expand...

Or modify/replace the existing flanges. It may be that the flanges can have some material welded to them and be re-drilled to suit the 11.x backing plates, or the flanges can be cut off the axle tube and replaced entirely.

I know that GM installed the 11.x" Duo-Servo brakes on "10-bolt" 8.5" GMT400 rear axles, if the correct option was selected when the truck was built. The 8.5" axle is capable of handling the added stress of the bigger, heavier drum, and increased braking force.

For that matter, I've got a set of 11" Duo-Servo brakes from a mid-'70s Monte Carlo with 8.5" axle that may replace the 9.5" Duo-Servo brakes on the 8.5" axle in the Nova.

However, it's good to know that the axle flanges are different on the GMT400 8.5" axles. The backing plates are not a direct bolt-on. That had not occurred to me. Probably should have, though. It'd have been nice if the 11.x brakes were a direct bolt-on.

In the end...I still support scrapping the 8.5 in favor of a 9.5 axle. Yeah, it's heavier. You'll never notice the difference in the way the vehicle drives, except when you step on the brake pedal.

b454rat said:

I read somewhere that the 'hoes have the bigger brakes, same as the 2500 6 lug trucks with the 14sf. Dunno....

Click to expand...

I've seen some 4wd Tahoe's in the yards with 11" brakes. But all the Burb's, C or K, got the bigger brakes. JB 6 package, gets you bigger and better, front and rear, than JB 5 which is what the 1500 pick-ups got.

Schurkey said:

However, it's good to know that the axle flanges are different on the GMT400 8.5" axles. The backing plates are not a direct bolt-on. That had not occurred to me. Probably should have, though. It'd have been nice if the 11.x brakes were a direct bolt-on.

Click to expand...

The flanges are indeed different. And they're both different from any other 8.5/8.6 that GM has produced before or since the GMT400. They don't interchange with anything else.

Ring and pinion, bearings, shim kit with crush sleeve. Option 4 would be the easiest, especially considering you want that (lame!) 3.42 gear. But I am most in favor of the 9.5" diff with some 4.10s.

Don't know what part of CT you're in, but check out these yards. DeMilo's (HTFD), A&B (E.HTFD), and Tom's (Bristol). Each yard has a 9.5" 3:42 gear rear. I'm in Manchester btw