3.90 differential install--Help!!
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Joined: Dec 2002
Posts: 69
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From: Livonia Mi
3.90 differential install--Help!!
I have a 6 sp. with 3.42 gears, I bought a differential with 3.90 gears and will try to install it myself. I got a copy of Corvette Fever magizne (April 01) they do a diff. change but removed half the car to do it. I have heard you can undo the lower ball joints and save a lot of work. Does anyone have any pictures or can give me advice on tools I will need and the ABC's of how to make the change. All advice will be appreciated.
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Re: 3.90 differential install--Help!! (Gee3)
I'm in the same boat. Don't know if you read my prior thread (link below) but it covered the same exact topic. There is a difference of opinion on what needs to come undone and how.
My game plan right now is to just undo the upper ball joints and drop the transaxle and then loosen the torsion tube as per Mike's site at:
mikemercury.home.att.net/342.htm.
http://forums.corvetteforum.com/zerothread?id=561870
It doesn't look so bad but PITA level looks to be up there. I'm figuring to do it in one full Saturday, perhaps into Sunday if necessary. I have a lift and tranny jack along with power tools so it should speed things up a little.
Mike's site also has all the torque specs to save time. He did a good job documenting his install.
My game plan right now is to just undo the upper ball joints and drop the transaxle and then loosen the torsion tube as per Mike's site at:
mikemercury.home.att.net/342.htm.
http://forums.corvetteforum.com/zerothread?id=561870
It doesn't look so bad but PITA level looks to be up there. I'm figuring to do it in one full Saturday, perhaps into Sunday if necessary. I have a lift and tranny jack along with power tools so it should speed things up a little.
Mike's site also has all the torque specs to save time. He did a good job documenting his install.
Pro
Joined: Feb 2001
Posts: 685
Likes: 0
From: Somewhere in the Mid West
Re: 3.90 differential install--Help!! (Gee3)
I did this myself in a 6hr time span without a lift.. It was not easy laying on the floor, but worth the experience. Instead of undoing the ball joint I simply took the whole upper A-arm off the car with the ball joint still attached. I tried and tried to remove the ball joint, but figured it wasn't worth the broken knuckles. Tools that are helpful:
- 3 hydralic jacks
- 4 jack stands OR 2 stands for the rear and 4 pieces of railroad ties(SP?) or equivalent under the front end of the car stacked 2 on bottom and 2 on top(Tick Tac Toe pattern)
- Torque Wrench (100ft/lbs)
- Compressor
- Impact gun and sockets
- Impact ratchet wrench and sockets
- Locktite
- Misc. tools (screwdrivers, prybar, wrenches, rags, etc..)
- 2 qts of Diff. Oil
- Friend (not needed) but very helpful.
- Lots of muscle if No friend available
Also, pick up a new O-Ring for that sits between the Diff and the Tranny. I don't have the part #, but Mike Mercury has it on his write up. He has great documentation on this http://mikemercury.home.att.net/342.htm. Get an alignment done as well sometime in the near future. Gook Luck!! :cheers:
[Modified by hrdtopv8, 11:15 PM 5/20/2003]
- 3 hydralic jacks
- 4 jack stands OR 2 stands for the rear and 4 pieces of railroad ties(SP?) or equivalent under the front end of the car stacked 2 on bottom and 2 on top(Tick Tac Toe pattern)
- Torque Wrench (100ft/lbs)
- Compressor
- Impact gun and sockets
- Impact ratchet wrench and sockets
- Locktite
- Misc. tools (screwdrivers, prybar, wrenches, rags, etc..)
- 2 qts of Diff. Oil
- Friend (not needed) but very helpful.
- Lots of muscle if No friend available
Also, pick up a new O-Ring for that sits between the Diff and the Tranny. I don't have the part #, but Mike Mercury has it on his write up. He has great documentation on this http://mikemercury.home.att.net/342.htm. Get an alignment done as well sometime in the near future. Gook Luck!! :cheers:
[Modified by hrdtopv8, 11:15 PM 5/20/2003]
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Re: 3.90 differential install--Help!! (hrdtopv8)
Good info. But did you loosen or remove the torque tube and after removing the upper control arms did you drop the whole transaxle? More on that would be appreciated.
Thanks! :smash: :smash:
Thanks! :smash: :smash:
Pro
Joined: Feb 2001
Posts: 685
Likes: 0
From: Somewhere in the Mid West
Re: 3.90 differential install--Help!! (78Vette-SA)
Did not do anything to the torque tube except loosen the TT cover (Removed half of the bolts). That's where a friend comes in handy. The extra person would pull the tranny down far enough so that the Diff. can just slide right out the back(and reverse the procedure for the install). BE CAREFUL not to let the tranny come to far down because the engine will rub up against the firewall..
After I took the A-Arms off I'll let the whole transaxle down using the 2 jacks and rolled it out of the way.. I wish I had pics, but did not have a Digi Cam at the time.. :nonod:
Here's the part# for the O-Ring: 12369456
[Modified by hrdtopv8, 1:09 AM 5/21/2003]
After I took the A-Arms off I'll let the whole transaxle down using the 2 jacks and rolled it out of the way.. I wish I had pics, but did not have a Digi Cam at the time.. :nonod:
Here's the part# for the O-Ring: 12369456
[Modified by hrdtopv8, 1:09 AM 5/21/2003]
Safety Car
Joined: Jan 2001
Posts: 3,879
Likes: 3
From: Hobart, WI
Re: 3.90 differential install--Help!! (Gee3)
link for my experience and some pictures:
http://forums.corvetteforum.com/zerothread?id=509986
Shortcuts are evolving. It is not nessisary to do anything inside the car with shifter etc. Remove the rear upper shock mounts to free rear carriage. Not nessisary to take down intermediate exhaust pipe from manifolds.
Not difficult.
Note: There is a team of two that do lots of these that are routinely <2 hours, drive in drive out.
[Modified by see5, 8:00 AM 5/21/2003]
http://forums.corvetteforum.com/zerothread?id=509986
Shortcuts are evolving. It is not nessisary to do anything inside the car with shifter etc. Remove the rear upper shock mounts to free rear carriage. Not nessisary to take down intermediate exhaust pipe from manifolds.
Not difficult.
Note: There is a team of two that do lots of these that are routinely <2 hours, drive in drive out.
[Modified by see5, 8:00 AM 5/21/2003]
