How hard to change rear end gears?
03-25-2018, 06:20 AM
#1
Burning Brakes
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Location: Somewhere near Fort Wayne, Indiana
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How hard to change rear end gears?
I've got a 96 with d36 and 2.59 gears.I'd like to change it to a 3.07 or better ratio. I've done gears in solid axles before, but the IRS is new to me. How hard is it to pull the center chunk and replace the gears? Would it be better to pick up another unit to build and then just swap? I know the batwing is different between the early years and late years, but is the centersection the same? As in, will an 84 differential bolt up to my 96 batwing? This is mostly a driver, but I'd like to do some autocross this year, so should I go for 3.07 or step up a little farther to 3.53?
Found some stuff...
https://www.corvetteforum.com/forums...hlight=batwing
Found some stuff...
https://www.corvetteforum.com/forums...hlight=batwing
Last edited by 64Scout; 03-25-2018 at 07:41 AM.
03-25-2018, 09:08 AM
#2
Le Mans Master
Depends on how you do it. Changing complete different diff with or without batwing is a weekend project. To change gear set will require some special tools and possibly carrier. You would want factory manual and watch YouTube videos then decide if it something you want to try. Installing used D36 3.07 assembly should be reasonable.
03-25-2018, 09:12 AM
#3
Race Director
I would think that anyone who is not a straight up professional driveline person would be better off replacing it as an assembly. Its pretty easy to screw up bearing preloads, and backlash.
03-25-2018, 09:30 AM
#4
Instructor
HAve a professional do it. I purchased a differential from Zip corvette's and it failed. sent it back for repair and the one I received failed a second time. went to a professional this time.
03-25-2018, 10:18 AM
#5
You mention 'experience' - Have you any experience with anything Dana/Spicer?
Removal of the assembly isn't an issue.
If you understand the FSM regarding the effort 4B-1 section I'd think you'll have few issues. You can fabricate your own spreader. You either understand set-up or not, only you know if you can or not.
Even if you bought a used 3.07 D36 you'll have to either 'trust' it's condition or have bearings, seals done and the differential checked.
How many miles on your 2.59? Any issues?
Do you have the FSM?
In that thread you linked I mentioned avoiding an '84 - that is a 'for sure'.
Removal of the assembly isn't an issue.
If you understand the FSM regarding the effort 4B-1 section I'd think you'll have few issues. You can fabricate your own spreader. You either understand set-up or not, only you know if you can or not.
Even if you bought a used 3.07 D36 you'll have to either 'trust' it's condition or have bearings, seals done and the differential checked.
How many miles on your 2.59? Any issues?
Do you have the FSM?
In that thread you linked I mentioned avoiding an '84 - that is a 'for sure'.
Last edited by WVZR-1; 03-25-2018 at 10:25 AM.
03-25-2018, 11:25 AM
#6
Safety Car
the other issue would be correcting the ecm for the new gear ratio. your car, like mine (also a '96) is a one year off regarding the computer. you would need to either buy a Jet interface box (or a clone Tech2, I believe they probably could change the ratio, but you would need to research) or search out someone able to reprogram the 96's, possibly a dealer.
the Jet interface/software that I have does all the recaculations
the Jet interface/software that I have does all the recaculations
03-25-2018, 01:08 PM
#7
Melting Slicks
Well I rebuilt a chevy 12 bolt from scratch once, yeah it came out okay, but truthfully, it wasn't easy. Personally, I'd sooner rebuild the engine. Take it to a pro with the tools and experience to do the job right.
If you mange to do the labor part on the car (disconnect the drive shaft, disconnect the axles / half shafts, separate the differential from the batwing and drop the differential, and then do the reassembly), the bench labor for setting up the differential with the new gears should be minimal and money well spent.
If you mange to do the labor part on the car (disconnect the drive shaft, disconnect the axles / half shafts, separate the differential from the batwing and drop the differential, and then do the reassembly), the bench labor for setting up the differential with the new gears should be minimal and money well spent.
03-25-2018, 01:27 PM
#8
Safety Car
My son just spent $325.00 to have a set of gears installed/shimmed in to spec by a shop that the owner builds and races his own stock cars. Other shops in the area wanted more so shopping around will pay off. Call some Napa places, other shops and see who they recommend. The transmission shop my son used was recommended. Then we actually saw his exhibit at the Power / Piston Show at the Cleveland IX Center.
We had the rear end out, delivered it to his shop and helped him take it inside to his bench was one reason for the reduced cost.
I would do all the U-joints if you go down this path as the drive/half shafts will already be out for the most part unless they have been done recently. (just my opinion to do preventive maintenance when it is already taken apart).
We had the rear end out, delivered it to his shop and helped him take it inside to his bench was one reason for the reduced cost.
I would do all the U-joints if you go down this path as the drive/half shafts will already be out for the most part unless they have been done recently. (just my opinion to do preventive maintenance when it is already taken apart).
03-25-2018, 08:20 PM
#9
Drifting
My son just spent $325.00 to have a set of gears installed/shimmed in to spec by a shop that the owner builds and races his own stock cars. Other shops in the area wanted more so shopping around will pay off. Call some Napa places, other shops and see who they recommend. The transmission shop my son used was recommended. Then we actually saw his exhibit at the Power / Piston Show at the Cleveland IX Center.
We had the rear end out, delivered it to his shop and helped him take it inside to his bench was one reason for the reduced cost.
I would do all the U-joints if you go down this path as the drive/half shafts will already be out for the most part unless they have been done recently. (just my opinion to do preventive maintenance when it is already taken apart).
We had the rear end out, delivered it to his shop and helped him take it inside to his bench was one reason for the reduced cost.
I would do all the U-joints if you go down this path as the drive/half shafts will already be out for the most part unless they have been done recently. (just my opinion to do preventive maintenance when it is already taken apart).
03-26-2018, 06:37 AM
#11
Burning Brakes
Thread Starter
Member Since: Oct 2017
Location: Somewhere near Fort Wayne, Indiana
Posts: 791
Received 103 Likes
on
71 Posts
You mention 'experience' - Have you any experience with anything Dana/Spicer?
Removal of the assembly isn't an issue.
If you understand the FSM regarding the effort 4B-1 section I'd think you'll have few issues. You can fabricate your own spreader. You either understand set-up or not, only you know if you can or not.
Even if you bought a used 3.07 D36 you'll have to either 'trust' it's condition or have bearings, seals done and the differential checked.
How many miles on your 2.59? Any issues?
Do you have the FSM?
In that thread you linked I mentioned avoiding an '84 - that is a 'for sure'.
Removal of the assembly isn't an issue.
If you understand the FSM regarding the effort 4B-1 section I'd think you'll have few issues. You can fabricate your own spreader. You either understand set-up or not, only you know if you can or not.
Even if you bought a used 3.07 D36 you'll have to either 'trust' it's condition or have bearings, seals done and the differential checked.
How many miles on your 2.59? Any issues?
Do you have the FSM?
In that thread you linked I mentioned avoiding an '84 - that is a 'for sure'.
Part of why I ask is because there is an early centersection with 3.07 gears on eBay for less than the cost of new gears.
My car has about 97,000 miles. I haven't had any issues with the differential, and it doesn't have any signs of leaking.
Last edited by 64Scout; 03-26-2018 at 06:43 AM.
03-26-2018, 06:48 AM
#12
All my experience is on Dana axles. D44, d44a, d35, d60, etc. I have a good friend who is well regarded in the local 4x4 community for gear changes, and if not him I know another guy who works for Dana setting up gears. There is plenty of knowledge and tools available to me. I do not have an fsm though.
Part of why I ask is because there is an early centersection with 3.07 gears on eBay for less than the cost of new gears.
My car has about 97,000 miles. I haven't had any issues with the differential, and it doesn't have any signs of leaking.
Part of why I ask is because there is an early centersection with 3.07 gears on eBay for less than the cost of new gears.
My car has about 97,000 miles. I haven't had any issues with the differential, and it doesn't have any signs of leaking.
I PM'd you and might like to share some information!
Last edited by WVZR-1; 03-26-2018 at 06:52 AM.
03-26-2018, 02:53 PM
#13
Instructor
I've got a 96 with d36 and 2.59 gears.I'd like to change it to a 3.07 or better ratio. I've done gears in solid axles before, but the IRS is new to me. How hard is it to pull the center chunk and replace the gears? Would it be better to pick up another unit to build and then just swap? I know the batwing is different between the early years and late years, but is the centersection the same? As in, will an 84 differential bolt up to my 96 batwing? This is mostly a driver, but I'd like to do some autocross this year, so should I go for 3.07 or step up a little farther to 3.53?
Found some stuff...
https://www.corvetteforum.com/forums...hlight=batwing
Found some stuff...
https://www.corvetteforum.com/forums...hlight=batwing
03-26-2018, 04:16 PM
#14
Le Mans Master
Member Since: Aug 2002
Location: Ventura County, CA
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Is it a necessity to install a new bearing/seals kit when doing the rear gears?
03-26-2018, 04:48 PM
#15
03-26-2018, 05:20 PM
#17
Race Director
03-26-2018, 06:36 PM
#18
Race Director
