Does the 2nd gear of the 997 transmission top out at around 62 mph (100 kph) and 3rd at around 90 mph like most cars?

A little off topic, but doesn't an Audi transmission fit onto the Boxster engine? I thought I wrote that down in my notes. I couldn't remember if the Audi transmission was just a cheaper option of if it also had ratio benefits.

 

Many audi engines have the same bellhousing bolt pattern as the boxter/996...

The critical part of the equation is if the transmission mount is in the same place. The 996 has three points of contact with the engine/transmission, so the transmission mount is pretty important.

 

my 996 2nd gear tops out around 74mph.

it kinda sounds like the swap might be worth it if converting a c4 to c2 or replacing a bad 996 box since used boxes r so much cheaper.

 

997.1 = 2005-2008. 997.2 arrived for 2009 model year with the 9A1 motor.

 

So I haven't found it yet, but, has anyone documented up the swap a little?
My 2nd gear has the feel of a gear headed south..

Just the details,
Mounts - any changes needed?
Electrical connection (Backup lights)
Clutch slave plumbing?
Drive line connection?

Cheers.

 

I too am considering this very thing. My 996 is in need of rebuild and a friend has a 997 S trans available. What I have today in a '99 996 body with G96.00 trans with factory LSD mated to 2002 3.6L engine. It seems the 997 S trans will bolt but that I need new cables because the shift linkage is on the driver's side (instead of the passenger's side) so the length is different. The cable connection might be different also but not sure about that. The unknown is the transmission mounting brackets opposite the engine side. Will my mount work? Do I need to make mods or find a different mount and if so what mount?

Thanks,
Gary

 

I've also seen comments about retrofitting a 997 shifter to a 996 so at least that bit sounds plausible.

The upside is the front mount is pretty simple,.

I was wondering of a turbo trans would fit , I kinda like the larger wide mount it uses..

 

I remember reading on another thread that the 997 transmission is actually bigger / longer than the 996 unit, making it a little tricky to install. From what I understand the main difference is you have to use 997 shifter cables because they are a different length. They also run on the other side so you have to get them away from some coolant lines. The only part I don’t understand is how the mount works but I assume worst case if the 996 mount doesn’t line up you have the use a 997 bracket.

 

The front mount is sort of T shaped, two studs on the body at the top of the T and then the front rubber mount has 2 bolts that go cross ways through the rubber mount at the lower leg of the T.

Either way the mount in front doesn't look too mad to change the length or width of. Probably easiest way would be to get the mount with the 997 trans so you have both and can sort the hole alignment out..
I'm looking a the C4 transmission, which adds the different front diff assembly.. I'd probably keep the 996 diff, and just adjust the driveline length if needed.

Be awesome if someone had the actual length from the bell junction to the front of the nosecone of both..

I keep looking at the used ones, but from what I can tell the 996 getrag is kinda like the 996 engine, some small glitches that add up to a 3-5K pain in the rear..

 

Gents,

I have successfully put a 997 C4S 6-Speed (G97.31 AISIN) trans into my 996 track car - a C2 that "identifies as a GT3" but is decidedly not. The stock trans was a G96.00 6-speed that started popping out of first, then second, started grinding going into 2nd when down shifting and rev matching. When I emptied out the oil there was "glitter" in the oil. Anyway, she is in need of a rebuild and a friend offered me a used 997 C4S trans for a very accommodating price and promised it would fit. Yep. It fit but it was a tight fit. Mainly the top of the trans oppose the engine side was a little higher than the 996 trans and was pushing up against coolant pipes, the front power/drive shaft "flange" was hitting some coolant rubber hoses, and the shift linkage is on the opposite side. It was a bit of a bugger to get to fit and make clearance but I got it. I haven't road tested it yet all seems to shift and engage properly. There is a little more stiffness in the shifting and that is probably due to the junkyard 997 shift cables being router around coolant lines and the transmission mount which caused a few higher stress bends. Not a show stopper but a difference. I did not try the 996 cables because folks on this board said you needed the 997 ones so I never compared them. I also called and emailed Numeric to talk to them about this conversion and how their cables might support this. Well, after 4 days of calls, emails, and voice mail with out a return call or email I gave up and bought the used 997 cables as per this forum indicated they would work and they were $125 with the body plug and insulation whereas the Numeric set was $500 or so. In retrospect the numeric cables probably would have made life much easier and the shifter feel smoother but they did not answer so I rolled the dice and went with the supposedly proven (and cheaper) option. The real trouble with the cable routing was the last bend to get under the transmission mount and align with the cable holder bracket. I could make plastic notched cable sheath cap fit into the bracket but it was with extreme force and a lot of residual tension in the cable assembly. I did not like that so I though (wrongly) I could rebend the bracket to give up an 1/8" to 1/4" favorable to relieve the stress. My tools and I did not have the talent to pull that off so I ended up cutting the bracket between the two mounting "forks" where the cable sheath cap locked in. I then cut and bent each piece individually to where I felt very little cable stress when bolted up. The only problem is one bolt hole is insufficient to hold the now individual bracket in place. Over time that would surely loosen up so I put a piece of metal between the two pieces and welded them together, as well as put a few dollops of weld to strengthen where I had cut and weekend the bracket. It felt very solid afterwards and with two bolt holes the bracket would now be fixed.

Again, if the Numeric cables were more flexible to aid with the routing and long enough to use the stock bracket w/o stressing the cable, that might have saved a ton of work and been a better solution - however since I don't know their length and flexibility to deal with the more tortuous routing path, I don't know. May have been the same problem in the end.

Sadly I did not take many pictures as I was working through this but I did take some. I will see if I can start a new thread title something like "997 Manual Trans into 996 Success." Give me a few days to get the pics that I do have and see how to edit them with arrows and such and then I will upload. I did want to give you guys my quick synopsis here as this thread did help me decide to do it and figure it out.

 

*weakened* the bracket...dang auto correct