5spd to 6spd ????

[grh]

Hello all,
Looking for info on putting a 6spd awd trans(G-64-20) into a 1994 c-4 that has a 5spd. Question! will we run into any issues as far as electric connections etc, just wondering what problems to look out for. Any info would be great!


Thanks!

[Bill Verburg]

you are opening a can of worms here, the 993 C4 trans is nothing like the 964.

993 AWD is passive, not hooked into any computer control other than ABS and ABD


The 993 C4 trans is not too different from a C2, it just has both ends of the output shaft available (but not required to use both) one going forward to the viscous coupler the other to the cup in the diff.. The 964 2wd and 993 2wd trans are easily swappable. The 964AWD trans can be swapped to 9932wd w/ a lot of effort.

the 964 AWD trans is totally different from any other trans. in that it has 2 co-axially located output shafts, you can't just disconnect the forward one as you can w/ 993 C4

The 964 is hooked into PDAS which controls 2 sets of hydraulically actuated clutch packs, 1 set is longitudinal the other lateral, also involved are 2 sets of accelerometers again 1 is longitudinal the other lateral.

All of the hydraulic are shared by AWD and ABS and ABD, it is possible to lose the brake fluid into the trans.


Joel Reiser did a 2 part series on changing the 964 AWD to 9932wd trans in the April ans Mat 2007 issues of "Panorama" you might want to read it.

[slammed1000]

whayne at ruf autocenter had a 964 ruf 6 speed forsale a while back that he hasnt sold yet....

[Bill Verburg]

You know I looked into this a little more it just might be doable, the front diff and torque tube is the same for 964 and 993, so you need a 993 G64 trans w/ the same cwp as the front axle(9:31 for n/a) and a 993 viscous coupler, You would still need to fool PDAS.

[grh]

Thanks for the info! This gives me some idea of what we would be up against.

Thanks again!

[ilko]

Are you thinking of putting a US 993 transmission in the 964?

[Garrett]

If you can get a C2 ABS control unit and the electrical connector plug from the harness, you can easily cut off the PDAS electrical plug, then splice the required inputs - they are all there. The PDAS just has a lot of extra wires not used by the C2's ABS control unit (accelerometer inputs, soleniod block controls, warning lights). Once you splice in the C2's harness plug to the existing harness' wires, you will have functional ABS and no need to "fool" the PDAS control unit.

Is the extra gear in a 993 tranny really worth losing the superior traction control system of the 964?

[grh]

Still not to sure what we are going to do. Just trying to get soom info on what sort of job we would be up against. What we want to end up with is a awd 6 spd car. Again thanks for the feedback it helps.

[slammed1000]

whayne at ruf said he is taking offers for his 6spd as his new trannys in. he asked me to make a offer. im sure the syncros are worn but it was built by ruf so im sure its pretty trick and overbuilt. i would say he would take $2500 for it....