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ghostryder
07-29-2014, 05:32 PM
I am doing the auto to manual tranny swap and I have everything I need my question is can I just swap the manual differential with the automatic differential or do I need to replece the entire rear end with the rear from the manual car?

thanks
Al.

Les Borda
07-29-2014, 05:57 PM
Al there is no difference between differentials, the only thing that has some differences are the gear ratio's depending on how they were factory ordered. Some 5 speeds like the 90 Cougar I had had 2:73 ratio, some are 3:08 some where 3:27's. I have never seen an automatic with 2:73's only 5 speeds.

I stand correction here if I am wrong so chime in :D

Come to think of I was the only one in Toronto with the torque monster 2:73's...I never did like it.

S4gunn
07-29-2014, 06:03 PM
I am doing the auto to manual tranny swap and I have everything I need my question is can I just swap the manual differential with the automatic differential or do I need to replece the entire rear end with the rear from the manual car?

thanks
Al.


I am doing the auto to manual tranny swap and I have everything I need my question is can I just swap the manual differential with the automatic differential or do I need to replece the entire rear end with the rear from the manual car?

thanks
Al.

Al:
I've done an auto to manual swap and IMO, there is no reason to do the swap immediately. Here's why:
- As far as I know, all manual SCs came with a TL unit so your donor car (the manual) should have a TL unit.
- Apparently, all auto SCs came with a TL unit unless your vehicle is a 94-95 (http://forums.tccoa.com/showthread.php?t=62731). In that case, it's an open diff so that's a reason to swap differentials.
- Your automatic probably has a slightly shorter gear ratio (3.08:1 or 3.27:1). IIRC, a manual SC had a 2.73:1 rear end. Therefore your speedometer might be slightly off if you kept the stock automatic but a) it will result in slightly better acceleration and b) you can always correct it with a different speedometer gear.

My suggestion:
- If the manual diff is free, take it. The TL is worth maybe $75.
- If your auto car diff is an open, consider swapping in the diff from the manual donor car first a) rebuild the TL unit and b) consider upgrading the ring and pinion gears to 3.55:1 or 3.27:1 gears. I have 3.73:1 gears in my diff but my car is a track car and I never bother with first gear anyway. You might actually want a first gear for the street.

ghostryder
07-29-2014, 07:58 PM
thanks for the help gents. I will put in the diff and fatter half shafts from the 89 donor manual car it doesn't seem too hard to do