turbo 350 question
Thread Starter
Cruising
Joined: May 2008
Posts: 14
Likes: 0
From: friendswood Tx
turbo 350 question
i have a 75 vette with a L-48 and a turbo 350 tranny
the problem is that the tranny will shift fine in first second and third but will not go any higher i am sitting at 4500rpm at like 70 does any one know whats up
the fluid level is fine its a littel over full i dont know if thats the problem or not
thanks guys you are life savers
the problem is that the tranny will shift fine in first second and third but will not go any higher i am sitting at 4500rpm at like 70 does any one know whats up
the fluid level is fine its a littel over full i dont know if thats the problem or not
thanks guys you are life savers
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
It won't shift any higher because it's a 3 speed automatic transmission and you don't have a fourth gear.
4500 is very high for going 70, but that could have a lot to do with rear end gears and tire size.
4500 is very high for going 70, but that could have a lot to do with rear end gears and tire size.
Thread Starter
Cruising
Joined: May 2008
Posts: 14
Likes: 0
From: friendswood Tx
it has the stock size tires but i dont know what gears are in it the car was in a barn for fifteen years and only has 25000 miles on it and before that it was just a weekend joy ride
what gears did the car come stock with
what gears did the car come stock with
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
I have no idea, but there is a code under the case cover of the rear end...it's hard to find, that will lead you to finding out the rear end gear ratio.
My 1977 with 3.08 gears, runs about 2700 RPMs at 70 MPH with relatively stock sized tires.
Drifting
Joined: Oct 2007
Posts: 1,458
Likes: 1
From: Collinsville MS
St. Jude Donor '08
clean off the bottom of the diff, right where the cover plate bolts up. should be a flat spot with the letters and numbers hand stamped in. Look for a 2 letter combination as follows:
AX or LR = 3.36 ratio
AC = 4.11
AB = 3.70
AA = 3.55
AW = 3.08
AV = 2.73
That is all provided the rear end hasnt been swapped out by a previous owner.
AX or LR = 3.36 ratio
AC = 4.11
AB = 3.70
AA = 3.55
AW = 3.08
AV = 2.73
That is all provided the rear end hasnt been swapped out by a previous owner.
Burning Brakes
Joined: Apr 2007
Posts: 1,028
Likes: 1
From: SOUTH ELGIN IL
If you can't read the codes you can turn the tires 1 revolution and count the number of drive shaft rotations. From there you should be able to estimate what you have.
I have a TH350 and run about 3700 at 70mph with 3.73 gears and 17" wheels. If you are running 800rpm more than me at the same speed you must have something pretty tall in there. Your next steps up would be 4.11 and then 4.56 I think - but 4.56 would be after market per L82shark's list above.
I have a TH350 and run about 3700 at 70mph with 3.73 gears and 17" wheels. If you are running 800rpm more than me at the same speed you must have something pretty tall in there. Your next steps up would be 4.11 and then 4.56 I think - but 4.56 would be after market per L82shark's list above.
Last edited by Dantana; May 27, 2008 at 02:26 PM.
