ssei bonneville trans in a n/a bonneville

tford

Registered Member
Joined
Nov 17, 2004
Is it a direct swap? The ssei is a 2000 and the sle is a 2001. Just bought the ssei with a blown head gasket for $200 to use as a parts car.
 
My experience is with the W-body (regal, grand prix) more than the Bonneville, but the experience should be the same when it comes to transmissions.

Typically the gear ratio in a supercharged car will be 2.93 versus your current 3.29 with the N/A transmission. Someone local to you with a powrtuner or HPtuners could put a transmission tune for the different gears into the car. There are benefits to the HD transmission, including the HD differential. You will need to use the HD axles from the SSEi as well, at least on the passenger side (not remembering if the drivers side is also different...)

I have also experienced varied results with the transmission cooler connections at the transmission. On older transmissions they were threaded connections, and with the newer ones they are a "quick connect" type with a locking spring/wire. You may not have an issue with those on the years you are looking at, but something to watch out for.

The torque converter is also different on the supercharged cars versus the N/A cars, as it is larger in diameter, and has a larger bolt pattern. There are some flexplates out there that have both bolt patterns, but not all that common. I would leave the N/A converter in the car, since it will not require a different flexplate, and you will want the higher stall speed for the lower powered N/A motor.

Swap the top end of the SSEi onto the SLE and you'll get a high compression supercharged car, which can be pretty fun. Obviously you need a tuner for all this.

Good luck.
 
Thanks for the detailed explanation. Hopefully I don't have to do this any time soon but I wanted a game plan in place because I know the transmission will be the first problem.
 
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