Let me preface this with - I have never had a problem with a manual transmission in 30+ years of abusing them in British, Japanese, and German cars.

When I first started tracking my 78SC in the fall of 2005 it shifted ok. I had a Wevo shifter installed and new Swepco put in during the cars build into a track car. Within a couple events I noticed that downshifting into 3rd I would get a little "snick" as it went in.. sometimes. This was regardless of rev matching, slow shifting, or how warm/cold it was. After about 15-20 events this became a substantial "crunch" EVERY time into 3rd so out she came. I had it sent to Gary Fairbanks, who said it was pretty trashed (I didn't baby it at the end) and he completely rebuilt it and added an LSD while he had the unit. Back in the car and it seemed fine... for about 5-6 days on the track. I now once again am getting the little "snick" sometimes, more on a downshift than up but it can happen both ways. I will yank it again this winter but i'm wondering if there is something I can do to beef it up or is this a $1500 - $3000 per year transmission? Gary is reputed to be one of the best 915 guys, and I will call him for advice but figured I would see what others have done..

Thanks!

 

I have had a little of what you described with 2nd gear. Figure its synchro wear. The only change I have made to it is a factory short shift. My 915 box has been realiable since I bought the car in 1999. The car has been pretty much a track only car since 2000 (club racing and DE).

The Po had it rebuilt 6 months before I bought the car.

 

I'm running the '81 SC in my avatar. I've done over 20 events at Sebring. Pulled the tranny and replaced the synchro's 1 time (it was a problem when I bought the car). I've added Swepco and a Weltmeister short-shift kit, and aside from the usual 1st gear problem it has worked fine. Go figure...

 

Thanks guys, as this will be the 3rd rebuild in 6K road miles and 40 DE days i'm giving serious thought to trying a different transmission guy. Fool me once and all that...

Sure wish Dan J. did transmissions!

 

Gary, I had Rennwerke in Elmsford do mine. I've got 25 DE days on it and it's been great. No issues at all. I went down to the shop to see the gear box when it was apart and he pointed out all the issues. I inspected the work before they put it back together as well. They did my clutch and a bunch of oil leaks while the engine was out as well.

 

Musante Motorsports...

 

Sacrilege!! ... if Dan Jacobs doesn't do rebuilds i'll figure something else out. Do appreciate the thought tho!

 

915 gearboxes arent magic, they are pretty easy to rebuild and it's easy to spot worn components. I am not a fan of Swepco gear oil in these boxes any more as some of the synthetics are just better, yes the 915 is picky about gear oil, but it can be done. I have a customer with a 915 in a car with a 3.6L engine and it doesnt kill itself all that quickly. I do gearboxes but am in MA. I wonder if fairbanks just overlooked something.

 

Gary Fairbanks does a good job. I have been dealing with him for 25 years. Make sure your shift linkage is adjusted right, and shift GENTLY. Don't tell the tranny you want 3rd gear, suggest it. I shift like an old lady and every time I bring my tranny down to Gary he can't believe I race it as there is so little wear. Also make sure your clutch is adjusted right and your pressure plate is good. Everything needs to work right, then it should be an excellent tranny unless you shift it like a race car

 

I'll be putting in a new clutch this winter and think I am going to get the Wevo bearing retainer installed when I get the tranny apart also. WIll be sure all parts in the chain are as perfect as I can make them and see what happens next year...

 

Dawe Motorsports.

 

Gary:
Mike makes excellent points about shifting a 915. You can't shift it like you do your 964. If you shift like he recommends, the 915 will perform well and last.

 

Believe me, I wrote a check two months ago for close to $3K for a rebuild and to have a used Porsche LSD put in.. I have been vigilant about not bashing on it. It may be a linkage or clutch issue for all I know. The main question was to see what others have done (if anything) to keep their 915 trans'd track car happy. Have learned a lot between here and Pelican in that regard, now to speak to my local guy and get chewed out for not just calling him 1st..

 

i agree w/ others about the 'way' you shift these. they can be silky smooth when done right, but you still won't be able to bang through the gears.

lots of people throw the wevo stuff "on top" of whatever condition 915 they currently own and expect it to work great. while the shifter feel is improved, it's only a band aid solution and the nice-feeling shift still won't fix the slop inside the box. it does make sense to put the wevo stuff on top of a fresh gearbox w/ factory-new tolerances, since at that point you have a healthy trans and the wevo stuff will take the human error factor out of the equation. it won't let you shift IM-precisely and will prevent you from adding wear-n-tear to a new box.

maybe when you get it done this time, you may want to add the wevo goodies to it as well? i've been tracking my bone stock 915 approx 3 yrs and it has slowly gotten worse to the point of needing a full-on rebuild. hopefully this winter. i only want to do this once so it will come back 'dealership new' when i'm done w/ it

 

The box was newly rebuilt when the Wevo shifter was added and I have had it in since day one..