Well today I got all the driveshafts out of the case. What a trick. That low growling noise that I get on cold startup, car in neutral, clutch out: looks to be a lightly spalled main drive / main shaft needle bearing. Fortunately the races on the drive shaft and drive gear look good. (Those are a couple hundred each)

And before anyone says it, I do want a cookie, and I'm going to get it now

Dave

 

Nice. I too have the same problem.

 

Good job...keep the pics coming. You need to do a How To write up on the tranny overhaul when you are done.

Tell me more about the tranny, what did it come out of, how many miles, etc.

Tom

 

Tranny and car have 61k, spend half its former life doing autox at the hands of Steve Wynveen (still active in an s2k). Mostly stock. I don't think he abused it, but in those circumstances the wear is greatly accelerated. I was a reluctant to take it to the track before I had the car fully sorted. (yeah, we all say that)

The 2nd synchro has always been a little rough and the tranny has made that noise for a few thousand miles. I decided to do the job for several reasons:

1) to replace the noisy bearing before the bearing gets so bad it ruins the races

2) to replace all the synchros, select spindle, t/o and pilot bearings, etc

3) to learn how to do it, I'm an engineer with a thing for learning "what's in there"

4) to make a nice writeup since nobody has really done one beyond the 5th synchro replacement. So far it seems that if you have a few specialized tools to get you by some tricky parts, everything is fairly straightforward. Having seen the wear on a few parts so far, I'm very optimistic that I'll see a great improvement if it all goes back together ok. I've got 150 pics so far, and details on how to build all the special tools and what's not really written in the FSM.

5) to do it on a budget, but to still do it properly. IMO you don't need all the SSTs, if you have a few modified pullers and sockets ready beforehand. It's a good thing this is a winter project since it can take several days for me to put together an appropriate tool for a few parts. To do this job in a weekend would require either a) all the SSTs and replacements already ordered or b) a really good writeup and all the tools built ahead of time. Hopefully b) will be an option for others when I'm done.

Dave

 

Dave,

Kudos to ya...that's awesome man. I'm sure your writeup would make for an excellent guide for others who are as adept as such tasks as yourself. It's always great to see forum members adding to the info pool on the forum, esp. how-to's!

~Ramy

 

Hello-

A writeup for SST creation would be great!

I used to deal a lot with older Porsche stuff. Many Porsche transmission rebuilders like to decribe the 901 and 915 gearboxes as some testy, magical, and mysterious chunks of metal that only a few trained professionals in the world could work on. The truth of the matter is that transmissions are pretty straightforward - all it takes is a couple special tools and some common sense. And, as you've found out, it usually isn't *that* hard to make/improvise them from other tools :-).

Retorquing those nuts properly is really, really important... if something goes wrong on the road, unlike your engine, you can't declutch and coast to a stop. Rather, you can lock up your rear wheels and go out of control - I've seen it happen with drag cars with big engines and not-so-big transmissions :-). The right tools are essential...

Some day I'm going to have to replace my 2nd gear syncro... its not exactly the way it was 90,000mi ago :-).

Take care,
Shad

 

3) to learn how to do it, I'm an engineer with a thing for learning "what's in there"


Good Eye Dave !! I like to do the same stuff as well, if it's broke, I fix it. Keep us posted and GOOD LUCK


PS - Did you make that 41mm deep socket ?

Tom

 

Looks like you're making some good progress. I can't wait to read the write-up once you're done. Although I would most likely not attempt to do this myself, (especially after looking at schematics of transmission internals) the engineer in me also likes to know how things work.

 

If you were watching over my shoulder, I assure you it wouldn't appear that way.

badddrx7, yes, the 41mm deep is on order, and there is a racecar chassis shop who will cut and weld in a section of pipe to make it deep enough.

bluerex, if you've got any engineering or mechanic sense I say it's not hard. Just time consuming. So far, I've been putting all the parts in zip-locs and scribbling where they came from FSM J-24 5 (4th synchro) and it's been very manageable. 90% of my time is lost fiddling with tool arrangements - once i get the puller/wrench/etc set up correctly, each step takes just a couple minutes. I thought I would need a big press for removing the last of the hubs and gears (as the FSM shows) but careful reuse of the gear puller appears to work fine.

I was worried about space in my tiny garage, but everything so far has been on a 5'x5' mat of cardboard and wood blocks in front of my workbench. Not much risk of breaking things once you get your 'sst's set up correctly. The only thing that has me a little worried is that I have seen some paint marks on a few gears and hubs that don't align to anything else in particular. I'm pretty sure they don't matter, but ??

I will reserve any back-patting for after I take it out and rake the gears, and even then I'll want to wait until it's lasted 10k without a problem. If it goes that well, I'll probably make my SST kit a little nicer and try loaning it out to people.

Dave

 

It seems to me that rebuilding them on a budget requires a lot of experience - as in, which components can be reused, which can be repaired, and which need replaced. For old boxes like Porsches, I'm sure the price for replacements is astronomical, and if the documentation is also scarce, then I don't blame them for protecting the experience they've invested. In many ways, there is no substitute for experience.

For FDs I think it's a little different - though this gearbox is not used in any other vehicle (that I could find at least), the parts and documentation are out there. It's mostly a matter of replacing all the wearing parts (synchros, snap rings, shift forks and some bearings) as extra insurance it will come out right. DIY in this case will take much longer, cost only a little less than paying a rebuilder, but get you more new components in the box for the same $$.

10-4 on that one. I was able to remove the mammajamma locknut by cutting, but I knew I'd need that socket made to get it torqued properly again.

Dave

 

Looking forward to updates Dave. I know this will be on my "to do list" one day.

Oliver

 

Know the feeling/curse
Can't wait to see it! I've got a full set of syncros and seals sitting on the shelf. Been there since 97' Was going to rebuild the 93's tranny, but totaled it. The replacment's (94) tranny was semi-OK, so never got around to tackling it.

 

Hello-

Well, you're right that Porsche North America charges ridiculuous prices for replacement parts. Then again, so much can be reused from core transmissions... and cores aren't that expensive at all (especially if one or more syncros are gone).

The documentation is anything but scarce. Heck, a $15 Haynes manual from Autozone will give you what you need for both 901 and 915 transmissions :-). Plus, the most important special tool, a shift fork jig, can be made from a spare case piece from a core for free or purchased from many retailers for about $20.

It does require some mechanical experience to be able to take a tranny apart for the first time and understand where things go. However, speaking from 1st-hand experience, it doesn't necessarily require previous transmission rebuilding experience. If you have some common sense around a machine shop, it's pretty straightforward. As you now know, it's just like any other shop job... 80% setup (gear pullers and whatnot for you) and 20% actual work gets the job done right :-).

The reality is that transmission rebuilding is far more infrequent than engine rebuilding, so less people are inclined to think that they know what they're doing. And, in the vintage Porsche industry, well, people can be interesting. Many find it necessary to maintain a facade of sophistication... after all, Porsche is a status symbol, right? But, once you get chatting with shop owners for a bit and they realize that you're a gearhead like them who won't pay $1500 in labor to swap out a couple parts, they usually level with you and are pretty groovy folk.


Exactly. And, as another engineer, it's kinda cool to see it all apart, huh? :-)

Ya know, while it's apart, you may as well get the car competition ready by plumbing in some squirters, a drain, an electric pump, and a seperate oil cooler... (j/k).

Best of luck!

Take care,
Shad

 

Thx Shad. If you could, please take a look at my thread about 2nd gear clunk - I'd like to have your opinion on it.

Dave

 

The turbo FC has pretty much the exact same tranny as the FD. Many external components are different, but the fundamental transmission itself is the same. Mazda calls it the Type R gearbox - no kidding .

Thanks for all the info! Tranny rebuilding is one thing I've always wanted to tackle. I'm probably gonna do a 5th gear job on my neighbor's FD at some point - his is toast. I think 5th gear is a good learning experience.

Dale

 

5th synchro isn't hard. I think the only special tools I needed were an extended gear puller (extended by 4 pieces of 3/4"w x 14"l 12 gauge steel bar with holes 12" apart) and a 1-1/4 socket for the locknut. Just follow the FSM to be sure you get all the parts. And don't damage the speedometer gear - the price on those is ungodly.

Dave

 

I know this thread is old, but did you or anywhere else come up with any good substitute for the SSTs? This transmission is a pain. I was able to use a press for the bearings but that stupid locknut... what about it?

 

Go get yourself a 42mm socket and cut it in half around the circumference. Now get about 1.5 feet of iron pipe and weld it in between the halves to make a socket that fits. That's what I did. You can borrow it for the cost of shipping if you want.

 

For the 42mm locknut you pretty much have to do that.

Another way to make it is to buy a 42mm crowsfoot wrench and weld a bar across the opening so it won't stretch open. Then you can use a breaker bar on it.

Dave

 

Cut a socket in two and weld the 6 point end to a tube that will slide on the shaft weld the other end , the square drive to the other end of the tube .simple as that.If you can not cut the socket in two let me know .These tranneys are not hard to rebuild .Easy to make long gearpuller links as well .

 

you wanna do mine next?

 

Would you be able to extend this offer to me? I'm in the middle of one right now and didn't realize how many special tools it takes just to get the gearsets out of the casing.

If you are still offering, I'd like to borrow the tool.

 

Try PMing him

 

Sorry VTEC.. I gave it to Crispy. He got the deal of the century that day.