speedo recalibration
Thread Starter
Registered User
Joined: Feb 2020
Posts: 60
From: VT
speedo recalibration
Guy's
I'm sure this has been covered a million times. I have done some searching of old threads, but I'm not finding the answers I'm looking for. So hear goes.
70 Cutlass S
TH350
rear gear swap from 2.56 to 3.42 this winter.
Greenish drive gear inside trans.(18 tooth?)
35 tooth driven gear stock (I counted today)
2 inch housing has 36,37,38,39 stamped on it.
Can I just swap the 35 tooth gear for a 45 or do I need a new 2 inch housing? Do I need to change the drive gear? I have a "Oldsmobile service manual" and there's a chart that covers speedo gearing. It says turbo hydro transmissions had 18 tooth drive gears and 3.42 geared cars with H78/14 tires (about the same diameter as mine) had 45 tooth driven gears. It says nothing about the housing. From this it seems I don't need to change the drive gear. However my reasearch elsewhere says I need to use a driven gear that matches the stamped number on the 2 inch housing. Am I on the right track?
Thanks in advance.
I'm sure this has been covered a million times. I have done some searching of old threads, but I'm not finding the answers I'm looking for. So hear goes.
70 Cutlass S
TH350
rear gear swap from 2.56 to 3.42 this winter.
Greenish drive gear inside trans.(18 tooth?)
35 tooth driven gear stock (I counted today)
2 inch housing has 36,37,38,39 stamped on it.
Can I just swap the 35 tooth gear for a 45 or do I need a new 2 inch housing? Do I need to change the drive gear? I have a "Oldsmobile service manual" and there's a chart that covers speedo gearing. It says turbo hydro transmissions had 18 tooth drive gears and 3.42 geared cars with H78/14 tires (about the same diameter as mine) had 45 tooth driven gears. It says nothing about the housing. From this it seems I don't need to change the drive gear. However my reasearch elsewhere says I need to use a driven gear that matches the stamped number on the 2 inch housing. Am I on the right track?
Thanks in advance.
Out of Line, Everytime😉
Joined: Dec 2006
Posts: 10,100
From: Melville, Saskatchewan
From TCI's website.
Buick, Oldsmobile & Pontiac transmissions use a 2.078" diameter driven gear housing. Two housings, each made from either aluminum or plastic, are available for driven gears with 34 or more teeth. One fits gears from 34 - 39 teeth and the second one fits gears from 40 - 45 teeth.
Buick, Oldsmobile & Pontiac transmissions use a 2.078" diameter driven gear housing. Two housings, each made from either aluminum or plastic, are available for driven gears with 34 or more teeth. One fits gears from 34 - 39 teeth and the second one fits gears from 40 - 45 teeth.
Thread
Thread Starter
Forum
Replies
Last Post
