Doing a Trans swap 900 S Turbo & 900 SPG

[ehsaylor]

I own an 88 900 S Turbo Convertible and am considering purchasing an 87 900 SPG Turbo for a transmission donor. Does anyone know for sure if the two are compatible? Is 87 the same as an 88? Any feedback is appreciated. Thanks.

[cdaly]

All the transmissions will interchange. The only difference between them may be the primary gear ratio though, given the S Turbo and the SPG they're likely to be the same. You can identify the primaries by the number '6', '7', '8' in the gearbox number with the higher number giving a higher ratio.

[eggsngrits]

Additionally, the 1989 and up transmissions use a larger pinion, therefore they are more durable than the earlier ones.