Porsche 964 transaxle...

[CliffBeer]

I know of a porsche 964 ('93 C2) transaxle which is rebuilt and available for a good price. The housing has "950 301 101" stamped on it. Does anybody know if this is a a) G50 b) which would work with the KEP adapter for SBF?

Thanks in advance.

[JohnC]

Cliff, here's a thread from awhile back on how to decode the tags on the different Porsche transaxles:

http://www.gt40s.com/forum/167685-post18.html

From what you've given, it looks like it would be a G50/03, without the LSD, and it could be from a 1990 to '94 C2 or a '95-98 911, depending on the date code.

There should be another stamping in the transmission with a letter code, and that will give you date of manufacture with K being 1989, L being 1990, etc. I don't know if the letter "O" was used or not....

HTH,

John

[CliffBeer]

Hi John,

Super, thank you, that's very helpful.

Looks like a nice clean and rebuilt tranny but I think I'll hold out for a G50 with the LSD.

If anyone wants this one just pm me - the fella is asking $1,800.

Thanks again.

[JohnC]

Sounds like a bargain, with used G50/50's going for $8K or better.

I paid $3.5K for my G50/03 couple of months ago.

[jmracecar]

This trans was on eBay not long ago. I wonder why it is for sale again....?

950 301 101 is probably part of the casting number for the center housing section. The real numbers are on the underside of this same section. They should start with G50...

[JohnC]

JM, since you're a Porsche tech, can you clear up the confusion on decoding the tags for these transaxles?

Any semi-official Porsche docs that you can post, or link to, would be appreciated.

TIA

[jmracecar]

OK, sorry for the delay. Here is my first draft of a response to this very reasonable question. It had to be pieced together from a number of places.

The main identification is on the bottom of the transmission, in the middle, on a raised surface, which is sometimes scraped from bottoming out on the pavement.

G50 04 3K 00542

This would be a G50/04

3 = index of "variants", example, 1L is plain 1990, 2L is M220 (LSD) 1990
K is the model year. K= 1989, L=1990, M=1991, etc.

00542 is the serial number, typically starts at 501, or 2001, or whatever.

The number on the side housing like 950.301 is just the casting part number for the housing -- tells us nothing really.

**The numbering was much shorter and less informative prior to 1988. So if you have an early G50 from 1987, or any 930 (early turbo), the numbers do not follow this outline. Otherwise, here we go.

G50.00 1987-1989** 3.2 Carrera, Rest of World version
G50.01 1987-1989** 3.2 Carrera, US/CDN/Aus/Jpn version
G50.02 1987-1989** 3.2 Carrera, Swiss version

G50.03 964 C2 1990-1992 1L is plain, 2L is M220
G50.04 964 C2 1990-1994 Swiss version
G50.05 964 C2 1992-1994 US/CDN version including RS America
G50.10 964 RS (street legal basic race car, non-US)

G50.20 993 C2 US/CDN/Swiss version
G50.21 993 C2 ROW
G50.31 993 C2 RS version ROW only
G50.32 993 C2 RS M003 (clubsport) version ROW only
G50.33 993 C2 RS Swiss version only

G50.50 3.3 Turbo 1989 first G50 turbo version (larger ring & pinion)
G50.52 965 C2 Turbo 1991-1994

Turbo = rear wheel drive
Twin Turbo = all wheel drive except for rare GT2 ROW race version
Carrera = rear wheel drive
C2 = Carrera 2 = rear wheel drive
C4 = Carrera 4 = all wheel drive

I will skip over most of the G64 (allwheel drive) versions, and all of the A50 (automatic, also known as Tiptronic) versions, and all of the Z64 front-drive transfer cases.

Some of the G64's can be converted to two wheel drive. That is another discussion.

Briefly:
G64.00 and G64.01 964 C4, not readily converted at all
G64.20 and G64.21 993 C4 trans, readily converted to 2wd
G64.51 993 twin turbo all-wheel drive trans, readily converted to 2wd

When the index of variants says there is M220 Limited Slip Diff, it only means that was what was in there in 1989 or when made, there could be something else in there now, or more commonly, a worn out limited slip diff that acts like an open diff. Also another discussion.

Now, what is/was the confusion? Whatever it is, it is probably understandable, Porsche did not make this simple, nor widely known.

My apologies in advance for any typos, errors or omissions.

[JohnC]

JM, thanks for that - the confusion I was referring to, are the various interpretations of this scheme which can be found all over the 'net. It's good to have the "real" info from someone who knows.

BTW, here's a pic of the code stamping from the bottom of my G50/03.

From what I had found earlier, confirmed by your decoding table, this "should" be a 1991 G50/03 with the M220 LSD, correct?

John

[jmracecar]

Correct. Exactly, that is what it "should" be. Select a gear & turn one output flange. If the other one spins in the same direction, it is a) still an LSD, b) still working. If they turn opposite directions, then it is either a) not an LSD, or b) not an LSD at the moment, and would need to be rebuilt with a fresh clutch pack. They do wear fairly quickly with track use or high power.

[Lynn]

Cliff,

These post '89 G50s are a bit long in their unmodified form for use in Mk I & II GT40s. It is my understanding that it is a pretty straight forward process to change the nose cap to an '87-'89 and shorten the shift rod to make them fit. There is one person, at least, here who cut off the round mount arm to make it useable. Another option to cutting off the shift rod is one of the CMS side shift setups.

Regards,
Lynn