4sp. ratio question
Thread Starter
Racer
Joined: Oct 2009
Posts: 441
Likes: 2
From: San Antonio TX
4sp. ratio question
how do you tell which ratio transmission you have ?
this is what I came up with as far as codes go ?
1976 Corvette Transmission Codes
Code Transmission
W Warner 4-Speed, Heavy-Duty Aluminum Case <<<<< This one
AM Turbo Hydra-Matic 350 with 350 L-48 Engine
XH Turbo Hydra-Matic 350 with 350 L-48 Engine
CZ Turbo Hydra-Matic 400 with 350 L-82 Engine
I can say it shifts pretty quick using the 3.36 rear end between 1st to 3rd ....in 3rd gear in town not even going over about 30-35mph with noticeable spread between 3rd & 4th
this is what I came up with as far as codes go ?
1976 Corvette Transmission Codes
Code Transmission
W Warner 4-Speed, Heavy-Duty Aluminum Case <<<<< This one
AM Turbo Hydra-Matic 350 with 350 L-48 Engine
XH Turbo Hydra-Matic 350 with 350 L-48 Engine
CZ Turbo Hydra-Matic 400 with 350 L-82 Engine
I can say it shifts pretty quick using the 3.36 rear end between 1st to 3rd ....in 3rd gear in town not even going over about 30-35mph with noticeable spread between 3rd & 4th
Last edited by Rmorgan&11; Apr 22, 2010 at 12:32 PM.
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
Spread between 3rd and 4th?... None of those automatics have a 4th gear. The TH350 has ratios of 2.52, 1.52 and 1:1; the TH400 has ratios of 2.48, 1.48 and 1:1.
Look at the trans pan - if the vacuum modulator is near the right front corner of the pan facing sideways, it's a TH400; if it's at the right rear of the pan facing aft, it's a TH350.
Look at the trans pan - if the vacuum modulator is near the right front corner of the pan facing sideways, it's a TH400; if it's at the right rear of the pan facing aft, it's a TH350.
Melting Slicks
Joined: Jul 2006
Posts: 2,292
Likes: 494
From: Salmon Arm, BC
I'm assuming you have a 4 speed from your description of running through the gears......Turbo-hydramatics are Automatic trannys.
As far as I know, you can tell the ratio by looking on the input shaft and you will see a number of grooves on the shaft. the number of grooves determines what ratio you have. I had a good link, but its dead now.
My tranny had 3 grooves....."W" code transmission (wide ratio)
Ratios
1-2.64
2-1.75
3-1.34
4-1.00
R-2.55
As far as I know, you can tell the ratio by looking on the input shaft and you will see a number of grooves on the shaft. the number of grooves determines what ratio you have. I had a good link, but its dead now.
My tranny had 3 grooves....."W" code transmission (wide ratio)
Ratios
1-2.64
2-1.75
3-1.34
4-1.00
R-2.55
Last edited by OMF; Apr 22, 2010 at 12:36 PM.
