Is it possible to upgrade an early 5 spd. tranny to GTS or GT specs?
Are the cases the same? If so, is it possible to just swap out the weak parts?
How much HP/tq can a 79 trans withstand?
Are the 87 and newer tranny's similar to the GT or GTS? What's the differences?

Thanks!
BB

 

Way too many question to answer without writing phone book size reply. Simple answer is that there really isn't anything common bertween first and last gearboxes except some critical measurements and simple cover bolts.

 

Anything is possible: so yes, with the caveat that you only get an open diff or mechanical LSD.

I have 88s4 5speed w/ LSD in my 81 (10/80).

 

How much did the tranny run you?

 

cliff notes.

early boxes 79 to 84 are ok, the weakest gears and synchros. usually all of them are tough to race and have grindy shifts as they age. 2.75 and 2.22 are the ratios

85 to S4 gear boxes (US) are all borg warner synchros and are butter to shift and are prett tough and can easily handle up to 400rwhp . 2.2 is the ratio . GTs are a little tougher still, with 2.72 ratios.

GTS gear boxes are even tougher, they have PSD Limited slip diffs and can handle more like 440rwhp
2.72:1 is the ratio. they are rare and expensive.

 

Thanks for the info. I'm just worried about a 79 tranny pushing 400hp...

 

Worry about making 400 rwhp first.

Then just keep your eyes out looking for a newer 5 spd with LSD like half the rest of us.

 

One thing that we have all looked over, is that ive been banging gears with a stock S4 box, racing it for almost 8 full racing seasons. it still shifts like butter! (was attached to up to 334rwhp and now 400ft-lbs of torque)

 

haha... I was waiting for that.

 

Wow, any special oil you use with it?

 

Mike, that right there is some funny stuff.

 

Mark only uses Castrol right?

 

Redline NS 75-90 Jokers!

 

not in the transmission and not in the wheel bearings.

 

After three (3) years of searching I got a deal for about $2K and shipping.
18 months after getting it, it was another $500 + deposit to get a rebuilt TT from 928 INTL.
I traded my Saab 9000 Turbo to my mechanic to install it for me.