DTFASTBEAR

The 915 tranny on my 86 Carrera has seen better days, especially the synchro’s for 1st, 2nd and even 3rd. After 155k miles, I am thinking about getting it rebuilt before we start time trailing next spring. I’d hate to be fighting with the gearbox trying to downshift and send the car off the track!

Should I be looking to have someone rebuild my own gearbox or should I look for a core exchange on a tranny already rebuilt?

What mods and other maintenance work should I consider at the same time with the transmission out of the car? The clutch is on its last legs, so I’ll have to replace that. My motor is stock, so I don’t think I need any sort of performance clutch. Thoughts on using 930 synchros?

What about the Wevo (sp?) gate shifter kit that is essentially an internal ‘gate’ for the gears? Does anyone have experience with this? Is it worthwhile? What about the higher performance "couplers" that I've seen.

Also, is a short-shift kit easier to install with the transmission out of the car?

I know there are a LOT of questions in here, but I’d appreciate any advice as I’ve never undertaken a project on a car that is likely to cost as much as this one. Speaking of that, any guesses on what this will cost me?

Thanks,

Dean
'86 Euro Carrera cab

pbs911

Personally, I would go with the exchange since my concern would be down time. My SC is my daily driver. If you go exchange, however, you may be getting a transaxle that was in worse condition than yours.

Also do all the numbers match on your car? If so and you want to keep it that way you would want to go with a rebuild.

As for the short shift kit, the installation takes place at the shifter lever and is easily accomplished with the trans in the car. Keep in mind that a short shift kit may put more pressure on the shifting mechanisms and decrease the life of the trany. These cars were not made for speed shifting. But a shorter shift pattern is nice.

Stephen Masraum

Personally I would prefer to have my tranny rebuilt, but it would be more convenient time-wise to just be able to swap trannies.
Get your tranny or rebuild from an expert. I think I have heard that Paul Guard is the best in the US. A well built 915 can shift very well, but I have seen more than one thread on newly rebuilt 915's that work horribly and need to be re-rebuilt.
I have seen a thread on the Wevo, but don't really remember the gist since I have a G50. I think it was on the Pelican Parts Forum.
I don't think the short shift kit would be much different since all of the parts go inot the shifter and it's inside the car.
It can be a good tranny, just get it done right the first time.
Hopefully you'll get more responses from people with more experience soon. I know the wait can be murder.

Steve Weiner-Rennsport Systems

Hi Dean:

Steve's advice is right on target; get your transmission rebuilt, not an exchange unit. There are SOOO many variations of 915 that you should get your own tranny back as you have the very latest & greatest version of this thing!

I offer this advice from experiences. We have been doing 915 overhauls & upgrades since 1975.

FWIW,....this is also be the most appropriate time to install an LSD, if you do not have one. Most of the labor is already accounted for when the tranny case is empty,...

Howard

Dean,

I am also looking to rebuild my tranny due to a bad sychro at 2nd, but I plan to do it myself since I would like to add an oil cooler and squirters since it's a track car.
I have seen ads by Vertex on core exchanges and the price seems reasonable (around $700) but I have no feedback for you as far as quality of work, I'm rather sure Vertex most likely subs the work out but I could be wrong. Here's the site - www.vertexauto.com if you are interested, let me know how it works out !
I've been checking prices on gears and synchros and just parts alone will cost $400-$500, FYI.
The factory SS kit is easily installed in the shifter housing, not the trans, the throw will be decreased at the expense of a more difficult shift due to less leverage, again, FYI.

emcon5

Dumb question: Keeping in mind that every one is different, what would a ballpark price be for a rebuild?

For argument's sake, say it we replace the synchro's for 1-2 and 2-3 and add a LSD.

Tom

Steve Weiner-Rennsport Systems

Hi Tom:

You are right on that one, there is no doubt that every transmission IS different.

Syncros are just a small aspect of the parts that wear and need replacement when a full overhaul is done.

Normally, a 125K+ 915 will need 4 syncro's, 2 operating sleeves (sliders), stop blocks, anchor stops, maybe some dog teeth on gears that have been hammered, and perhaps a pinion bearing. Every one is different,...

LSD's vary in price by which type is to be installed. The labor is the same; the parts cost is not. Parts required are the LSD, and a set of ring gear bolts and locks.

We charge 8 hours labor for a 915 overhaul; add 3-4 hours if an LSD or ring & pinion is installed.

In short, there is no typical overhaul cost due to the wide variations in conditions found in Porsche transmissions. These things seem to be abused a lot more than engines do.

HarryD

Dumb question. What's a LSD?

DTFASTBEAR

HarryD, it's a Limited Slip Differential.

Thanks to everyone for all the advice!

Anyone care to comment on using 930 synchros? I've heard they are "toothless" (I don't know what that means) and that they would be preferable for the Time Trial events I'll be running next year.

Thanks,

Dean

Carrera51

Dean:
I think you would be better off getting your trans rebuilt as opposed to swapping it for one already done. I here that CA has the highest concentration of Porsches of any state, so I would guess that there are plenty of reputable shops that can handle rebuilding a 915 box. I wouldn't waste your money on a short shift kit. I don't have one in my 84 and I club race and do a lot of DEs every year and my trans has been fine after 2 + years of track driving. A friend had an 80 SC that had a non factory short shift in it when he got it. He ended up having a gear box rebuild after losing 1st gear and his mechanic thought that the short shift contributed to the problem. Definately drop an LSD in it while it is apart. My 2 cents.

DTFASTBEAR

Thanks, everyone, for the advice. Given what I've read here in addition to advice from my local PCA group, I think I will get my own core rebuilt rather than buying another unit. It removes a big variable for me, as I know what this tranny has (and hasn't) been through!

No one seems to be very supportive of the short-shift kit, so I think I'll avoid that, at least for now.

I hadn't really considered an LSD, but that might make sense. My euro motor moves me out of stock class in PCA events, anyway. Any recommendations on whose LSD is best?

Still no comments on using 930 synchro rings... I haven't found info on this anywhere, but a trusted source told me to go that route.

Thanks again!

Dean

Thom Fitzpatrick

I don't recommend dropping any LSD in there, as it tends to make the giraffe dinner plates wobble green telephone cam exponetially...

Carrera51

Thom:
Could you explain your last comment? I don't get it.

Dean:
A euro motor puts you in E-class for club racing. That's where I run my car due to the non-stock brakes. I recommended a limited slip if you are taking the car on the track. I have driven my dad's 964 on the track (which doesn't have LSD) and sometimes I experienced wheelspin in tight corners under acceleration. My 84 has the factory LSD (according to what PCNA told me when I called to see what it came with from the factory after I bought the car. I gave the woman I spoke with the VIN and she read off the list of options that the car came with.

Howard

Carrera 51,

I think what Thom was referring to was ...you know...LSD....halucinigenics.....LOL.

Pretty funny Thom...LOL