F2 Iceland

993 6speed gearbox C4? Does it fit in a 93' 964 c4

Any1

Geoffrey

Yes, it will physically fit.

pete000

six speed 964's are sweet !

HoBoJoe

So a 993 C4 trans fits into a 964 C4? What are the modifications required if any?

Chris M.

Someone on here has one and his username is something like TTAmericaRoadster. It's a 993TT engine with 993 6 speed AWD tranny in a widebody 964 cab.

CWay27

Is a 6 speed tranny from 993 a common mod. for 964? Beside the 6th gear, are there any advantages in doing it??

Ritter v4.0

When I frequented the 993 forum, I seem to recall some actually putting in 964 5 spds due to better spaced ratios than the short 6 spds. Guess the grass is always greener . . .

TRINITONY

yup a few of them have...think they said 6th is worthless or the gearing is too far apart so they choose the 964 box....i could do with another gear..lol

jeff522

I asked the same questing a few years ago. Most or the responses were negative. Examples; st gear is to short making city driving a pain. The ratios don't go well with the 964 rear end. Which means you need to change the finial drive ratio. The list went on. Needless to say I stayed with the 964 trany.

Tom W

Gearing is a matter of person preference and need.

My daily driver is a 993 with a 6-speed gearbox that was re-geared to shorter gearing about 5 years ago. It's quite nice and only a pain in stop-and-go traffic (but thats mainly due to the LWF, IMO). The stock 964 5-speed is less than optimal for track work and I can't imagine anyone thinking it would be an "upgrade" for anything but putt-putting around town when you are too lazy to want to shift. It is certainly a performance downgrade. I will likely pull the 6-speed out of the 993 and put it into the 964 this winter (and the 5-speed will go into the 993 until I can find a good used 6-speed gearbox).

Strega(UK)

The 993 system uses self contained viscous clutches in the diffs so does not use the complicated hydraulics of a 964, so I believe you have to fit the 993 setup in there. I think the ABS might also need some work too as it's probably all tied into the same thing. Basically, if you have a totalled 993 sat spare, swap the lot over!!

A guy a few miles down the road did it and he said he was very pleased with the handling afterwards.

Geoffrey

The 993 uses the exact same ring and pinion ratio as the earlier 964s (3.444) and is not that far off the 3.333 of the later transmissions.

Mark Brook

911 and Porsche World did an article on it a couple of years back. I'll try to dig it out.......

Bill Verburg

Some of the tt guys professed a strange desire for 5 spds, I speculate that the tts are torquey enough to not need the 6 spd to keep them in a usable pwer band.

Here's a compilation of most of the g50 5 speeds. all w/ the same rev limit and tire choice


For a dual purpose car i like to keep ~160 for a top end, this retains a reasonable rev level on the interstates.

Here is a compilation of 6 speeds

the issue w/ the stock North American 6 speeds is the overly tall gearing

PAOLOP

No, this doesn't fit.
You sholud replace all trans items.

Paolo