The speedo is corrected with purchasing new 'speedo gears' that get installed in the tailshaft of your transmission.
Rearend Q's
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 859
Likes: 7
From: Spring Texas
St. Jude Donor '05
Rearend Q's
I have a '90 Automatic with the D36 and the 2.73 ratio - My question is...
Is there a better ratio for the D36 (3.55 or 3.73)? Or... Will I need to find a D44?
Also, I think I was told or read here on the forums that the D36 to D44 swap required more then just the "batwing" to install.. yes / no?
If so, can anyone supply me with a parts list or direct me to one or... maybe someone who has everything I need to do the swap
Thanks for the help
Is there a better ratio for the D36 (3.55 or 3.73)? Or... Will I need to find a D44?
Also, I think I was told or read here on the forums that the D36 to D44 swap required more then just the "batwing" to install.. yes / no?
If so, can anyone supply me with a parts list or direct me to one or... maybe someone who has everything I need to do the swap
Thanks for the help
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
D36 to D44 swap requires...
Dana 44 Differential (Pumpkin & Batwing)
Dana 44 C-Beam
Manual transmission Driveshaft (~1" shorter than yours is)
I don't think your 2 series D36 carrier can get a shorter gear. If you had a 3 series carrier (3.07s) then you could go up to a 3.73 I think. I don't know if you've done anything to your car, buta stock L98 really won't benefit from anything over 3.07s.
Dana 44 Differential (Pumpkin & Batwing)
Dana 44 C-Beam
Manual transmission Driveshaft (~1" shorter than yours is)
I don't think your 2 series D36 carrier can get a shorter gear. If you had a 3 series carrier (3.07s) then you could go up to a 3.73 I think. I don't know if you've done anything to your car, buta stock L98 really won't benefit from anything over 3.07s.
Thread Starter
Burning Brakes
Joined: Apr 2004
Posts: 859
Likes: 7
From: Spring Texas
St. Jude Donor '05
The car has headers & no cats, SR intake, 24# injectors, 1.6 RR's, 52mm TB, custom chip - It runs good, but I want better...
anything better than a 2.73 has got to help... once it gets rolling it runs great.
So... what do think? Look for a D44 w/ 3.73's?
anything better than a 2.73 has got to help... once it gets rolling it runs great.
So... what do think? Look for a D44 w/ 3.73's?
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
check this one in parts sale section for D44 :
http://forums.corvetteforum.com/show...02&forum_id=55
http://forums.corvetteforum.com/show...02&forum_id=55
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
3.73 is too much for the automatic, 3.33s would be good if you can find them, 3.07s are all the SR or the L98 needs though.
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Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
you should be able to find a D36 with a 3.07 rear... (mine has one)
You might also want to look at some '84's. They came with a 3.07 rear standard, and the 'performance' RPO'd cars came with a 3.31 D36 (or was it a 3.33).
You might also want to look at some '84's. They came with a 3.07 rear standard, and the 'performance' RPO'd cars came with a 3.31 D36 (or was it a 3.33).
Last edited by mikey whipreck; Jun 14, 2005 at 08:32 AM.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Originally Posted by mikey whipreck
you should be able to find a D36 with a 3.07 rear... (mine has one)
You might also want to look at some '84's. They came with a 3.07 rear standard, and the 'performance' RPO'd cars came with a 3.31 D36 (or was it a 3.33).
You might also want to look at some '84's. They came with a 3.07 rear standard, and the 'performance' RPO'd cars came with a 3.31 D36 (or was it a 3.33).
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by scorp508
I'm sure someone will correct me, but in '84 wasn't the 2.59 standard, the 3.07 "performance ratio" and 3.31 optional only if you had Z51?
Where's CFI-EFI when I need him?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Rat Cheer!
The 3.07: ratio (RPO# HE3) was the standard ratio in 1984, standard or automatic. The 3.31:1 gears (RPO# GW4) were the "performance option" for the '84 and required the Z51 handling package. The Z51 didn't automatically come with 3.31's. Most were built with the 3.07's, but Z51 had to be specified to get the GW4. The 3.31's are pretty rare. Out of 51547, 1984's built, 410 were equipped with the 3.31 gears.
RACE ON!!!
The 3.07: ratio (RPO# HE3) was the standard ratio in 1984, standard or automatic. The 3.31:1 gears (RPO# GW4) were the "performance option" for the '84 and required the Z51 handling package. The Z51 didn't automatically come with 3.31's. Most were built with the 3.07's, but Z51 had to be specified to get the GW4. The 3.31's are pretty rare. Out of 51547, 1984's built, 410 were equipped with the 3.31 gears.
RACE ON!!!
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by CFI-EFI
Rat Cheer!
The 3.07: ratio (RPO# HE3) was the standard ratio in 1984, standard or automatic. The 3.31:1 gears (RPO# GW4) were the "performance option" for the '84 and required the Z51 handling package. The Z51 didn't automatically come with 3.31's. Most were built with the 3.07's, but Z51 had to be specified to get the GW4. The 3.31's are pretty rare. Out of 51547, 1984's built, 410 were equipped with the 3.31 gears.
RACE ON!!!
The 3.07: ratio (RPO# HE3) was the standard ratio in 1984, standard or automatic. The 3.31:1 gears (RPO# GW4) were the "performance option" for the '84 and required the Z51 handling package. The Z51 didn't automatically come with 3.31's. Most were built with the 3.07's, but Z51 had to be specified to get the GW4. The 3.31's are pretty rare. Out of 51547, 1984's built, 410 were equipped with the 3.31 gears.
RACE ON!!!
Cool- I wasn't sure how they were optioned, but I was pretty sure that the gearing was either 3.07 or 3.31. I didn't realize the 3.31 was that rare though...
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
The option code GW4 is listed as good for 1984 and 1985, only. I don't have the 1985 info, that I do on the 1984. Therefore I can't confirm or deny if the 3.31's were available in 1985 or not. I do know that GM and Dana discontinued the 3.31 gears, early on. The 3.33 is a Dana 44 ratio.
RACE ON!!!
RACE ON!!!
