Bonzai_7T

Hello all -

It's been a while since I've been on here.. anyway.

I recently decided to go pick up my 7 after lending it to someone for a few years. Well the transmission isn't as nice as when I left it and now the person has lost the title.. lame. Anyway to the question

Can a 91 TII transmission directly bolt into an 87 TII Car? What are the big differences between the 2 transmissions (if anyone happens to know)

Thanks!

Turbonut

iTrader: (1)

You'll need the trans crossmember out of the S5.

arghx

iTrader: (3)

The 87 TII has a different 5th gear synchro than 88+, as I found out when I got my tranny rebuilt. gearing is also shorter on the s4's in general.

farberio

iTrader: (7)

fifth gear is a different ratio between them. But they swap in with no problems using the transmission series cross-member.

Bonzai_7T

No way to make the S4 part work? Anything else other than that? Do you happen to know if it's a stronger box at all?

Bonzai_7T

wow.. a little lag on the board.

arghx

iTrader: (3)

no s5 trannies will swap in just fine. I have put an s5 n/a tranny into an s4 n/a by swapping the crossmember. I'm just saying that the s4 and s5 are not the exact same trannies.

The s4 does have very short gearing though. When I drive an s4 T2 and then an FD I notice a difference.

Turbonut

iTrader: (1)

I've never tried it, but some have said that the tail shaft can be changed e.g. put the S4 tail shaft on the S5.
Maybe someone will chime in that has done this.

The TII gear ratios are the same except for 5th. The S4 .762 and the S5 .719. Maybe 150 RPM difference at 70.
Actually the S5 is the same gearing as the FD.

RotaryEvolution

iTrader: (30)

the transmissions are almost identical, you can swap the tail housing or you can use the crossmember as others have said. you need the mounts as well, the S5 has a V mount at the tailshaft where the S4 has a flat mount onto the tail housing. neither is superior but they are different. in fact just about all the parts for S4-S6 are interchangable, just the FD transmission bolts in way different than the rest but is no stronger, in fact, the shorter throw in the shifter results in more cracked syncros than in FCs.

Bonzai_7T

Wow. ok thanks for the info guys. Between the 2 of them I'll get something workin.

RotaryRocket88

iTrader: (7)

His location says Japan, so I'm gonna take a guess that he'll be using J-spec transmissions. ALL J-spec transmissions have a 0.806:1 5th gear. It's not like the US-spec transmissions with different ratios between S4 & S5. I have one of each J-spec transmission actually, and the shorter 5th gear makes for some high freeway RPMs. 80mph is at ~3600 RPM, but I can still manage low 20s MPG on the highway.

But as far as case design and crossmember/tail housing interchangeability, it's the same as US-spec transmissions. The crossmember must match the tail housing.

farberio

iTrader: (7)

I didn't know that about J-spec trans.

And apparently I did not read his location all that closely.

RotaryRocket88

iTrader: (7)

^ Me either until I ended up with 2 of them and wanted to know what ratios they really had. Going from a 0.711 (NA trans) to a 0.806 5th gear took some getting used to, but there's next to no downside anyway.

Bonzai_7T

Thanks for the info guys. Lame me forgot to change my location back from Japan.. sorry (haven't logged on in 3 years) I'm in Florida now.