Swapping in a higher ratio transaxle - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 03-02-2007, 06:17 PM   #1
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Default Swapping in a higher ratio transaxle

Howdy. We're dealing with my '89, 440T4/4T60, with 2.97 gearing according to original specs.

Since I don't have enough money to do the 6 speed manual project, I want to get a good, kinda lower mileage 440T4 to swap in. Does it matter which one I get? I imagine it has to be like 1988-1990, the newer the better if there have been any updates.

Are the axle splines different at all? And, most importantly, can I get one with a higher axle ratio? If I do, will my odometer/speedometer be messed up, or can it be reprogrammed in the memcal? Or can the drive gear be changed? Thanks.

I know that it'* going to give out in time though due to the supercharger and all, but it'll buy me some time. The last one lasted 172k miles
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Old 03-02-2007, 06:51 PM   #2
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Also, is it true that Pontiac transaxles shift firmer than Buicks? Even without electronic controls?
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Old 03-02-2007, 10:19 PM   #3
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I believe the 4t60 (non e) equipped w bodies came with a 3.33 fdr. And I know the LN3 bonneville had the option of comming with the 3.33.
You will need to adjust the pcm IIRC. Just ask Ryan about that.
Not sure on the whole shifting harder thing.
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Old 03-02-2007, 11:00 PM   #4
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To confirm Mike... and assuming you mean a lower gear ratio(higher numerically)

2.97:1 is a 3.33:1 diff geared up with the 37/33 drive/driven chain gear. You can order new chain gears for around $280 to your door from GMpartsdirect.com , plus a chain you'll have to probably find from a dealer. They had two different types of chains. Roller joint, and rocker join. I don't recall for certain, but I think the rocker joint chains were the latest and greatest from GM. The same design applies to the chain gears. You can run a 35/35 to have a 3.33:1 FDR, or you can run 33/37 for a 3.73:1 FDR. Don has the manual that has the part numbers for the chain gears and chain. Maybe if this is what you're looking for you can get the numbers from him.
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Old 03-03-2007, 12:03 AM   #5
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3.73 would be wicked, but I don't plan on having the auto very long so it wouldn't be worth it to rip it apart and change them, to me at least. Since I'm gonna pickup a junkyard pull, I figure I might as well get something a little higher.

But thanks guys. I'll email Ryan
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