rb20 transmission with rb25

[jrock7885]

I just got my rb25det today i got it at a really good price but it is automatic.I have a rb20 transmission and was wondering if it would bolt up. please help thanx.

[dillards1234]

I am pretty sure that the RB20 bell housing is smaller the the RB25's bell housing not to sure though

[pirate87]

I am pretty sure that the RB20 bell housing is smaller the the RB25's bell housing not to sure though

not true, all RB bell housings are the same size. You'll need to remove the auto transmission bearing and replace it with a manual transmission pilot bearing. The bearing from a 300zx works, and its should be about $3 at autozone.

[240z4u]

Trans is physically smaller, but the mounting holes are the same.

Evan

[Cjmartz2k]

I will work, just don't do more than bolt on's to that RB25 motor, or you'll eat that transmission alive.

[DriftingisLame]

The rb20 trans is similar to CA/SR/KA trans, they can see about 400 tq, and are proven to be much weaker than the RB25 trans. They are lighter however..

You can bolt the RB20 trans to any RB block.

[dillards1234]

yeah thats right the trans is smaller but the bell housing is the same size. never needed to see if a rb20 trans would fit so yeah...

[Coolwhip]

you can bolt on either RB transmission onto either RB engine. The bellhousings from the RB20 and the RB25 are completely different and will not interchange.

the RB20 transmission will have no problem holding up to the task of the RB25. However, like said its inferior to the larger RB25 transmission.

Again, the 20 transmission is the same as the SR/KA gearbox. As many have seen those gearboxes have held some pretty large number setups but will show its reliability issues when pushed to extreme limits.

[jrock7885]

thanx everyone for the info it looks like im going to use the rb20 transmission.

no custom drive shaft for now.