3.91 diff install help/ pointers

[Jerry7297]

I will be getting a 3.91 differential in this week from Apex ( Thanks Chase). I see help with various parts of this kind of install. Can anyone chime in with install tips on any part of this install? It could be anything from axles to diff bushings. All help will be appreciated. Myself and some buddies plan on tackling this soon.

[Scott@Bjorn3D]

Get some new drive shaft bolts for the rear end. The drive shaft bolts are a torque once and may or may not hold being put back in again.

[Jerry7297]

Originally Posted by Scott@Bjorn3D

Get some new drive shaft bolts for the rear end. The drive shaft bolts are a torque once and may or may not hold being put back in again.

Thank you sir, will do.

[woodside783]

Where can I find these bolts?

[HardrockSS]

[OnkelMatze]

Prop to coupler:
Bolt-92228335 (x6)
Washer-92228334 (x6)
Nut-92228333 (x6)

Coupler to diff yoke:
Bolt-92139104 (x3)

Coupler to trans yoke:
Bolt-92138569 (x3)
Nut-90538867 (x3)

http://onlinegmparts.com/

[954camaro]

^ which are the ones I need to just replace the driveshaft bolts? And once you got that 1le differential there isn't anything else we need to get for the install right? Just the driveshafts bolts?

[Jerry7297]

Originally Posted by OnkelMatze

Prop to coupler:
Bolt-92228335 (x6)
Washer-92228334 (x6)
Nut-92228333 (x6)

Coupler to diff yoke:
Bolt-92139104 (x3)

Coupler to trans yoke:
Bolt-92138569 (x3)
Nut-90538867 (x3)

http://onlinegmparts.com/

This is disturbing cause I have taken off my drive shaft from my diff before and reused the bolts....

Are all those needed? It looks like we will just drop the rear cradle and remove the diff / axles from stock diff and reinstall them into new diff. Then bolt everything back up....

Here is a pic of the new diff. I will be replacing the diff bushing.

[strych9]

Originally Posted by Jerry7297

This is disturbing cause I have taken off my drive shaft from my diff before and reused the bolts....

Are all those needed? It looks like we will just drop the rear cradle and remove the diff / axles from stock diff and reinstall them into new diff. Then bolt everything back up....

Here is a pic of the new diff. I will be replacing the diff bushing.

Whatever driveshaft bolts that get removed for the diff swap will need to be replaced. No more, no less.

[Mr_Draco]

Originally Posted by Jerry7297

This is disturbing cause I have taken off my drive shaft from my diff before and reused the bolts....

These bolts are torque to yield and are designed to stretch when used and need to be replaced every time they are removed. You may not have had an issue yet but whose to say that the next time you use them, you won't stretch them beyond their limit causing a catastrophic failure while you're driving.

[Jerry7297]

Purchasing new ones now... Thanks to everyone for the help so far.

[954camaro]

If i am having a chevy dealership install my diff would they replace them for me?

[Mr_Draco]

Originally Posted by 954camaro

If i am having a chevy dealership install my diff would they replace them for me?

They are suppose to (you will have to pay for them if they do) but you are asking about a dealership here and they are not known to be the brightest of the bunch. The mechanic may not even know to replace them, also these bolts are a low demand item so they may not even have any in stock.

It would be safer to ask them if they are going to replace them or if you need to bring your own.

[Jerry7297]

I called a dealer today in town they did not have any of the bolts. Said it would take a week to get in. I am ordering from GMpartsonline.