915 rebuild

[jeff parker]

Trying to decide if I should try it myself or call Gary Fairbanks. I know some guys on here have rebuilt theirs. My thought are:

1. Will it really be much cheaper if I DIY?

2. Will it work when I'm done?

3. Will I just screw it up and have to pay somebody to fix it anyway?

[1980SC]

Uh, it depends...

I'm doing mine right now. It's really not that hard.





Rob
1980SC

[Jdub]

Do use fresh newspapers though.

John ;>

[VincentVega]

If you have the time and space it might be possible. However, I've read the Mr. Fairbanks results are great and not all that pricey. I could see how a successful rebuild could be very satisfying though.

[scca_ita]

I was going to try to rebuild mine as well. Where could I get information on how to rebuild a 915?

[Porschephanatic]

Wayne?

[on-ramp]

Originally posted by 1980SC
Uh, it depends...

I'm doing mine right now. It's really not that hard.





Rob
1980SC

quick question.....is the assembly idiot-proof? in other words, is it possible to assembly components backwards and still have the whole thing come together?

[marcesq]

some components can be installed in reverse (no pun intended) and fit together. That's what I gather from reading the various sources as I approach my rebuild in the coming weeks.

[Tinker]

Transmissions are no big mystery. The Haynes manual for the 911 has a exploded/blown up picture of the correct gear order on both the input and pinion shafts.

Before you begin, you should have some idea what is wrong with the trans; ie noisy, grinds, ect. That will give you an idea what to pay closer attention to when disassembling. The hardest part will probaby be the inspection of parts since you will have no idea if something looks worn, but the symptoms/driving experience will give you some ideas. You can always post pictures in this forum and someone is sure to respond. If you cheap you can always flip syncos to get more life out of them. But if things are worn and its popping out of gear, new dog teeth and sliders are recommended at a minimum. Parts are not too expensive.

You will need a few special tool, especially when torquing the flange nuts on the end of the shafts, but you can cheat with an air wrench by marking the nuts before removal or by using an old clutch disc to lock the shafts.

I taught myself on a 915 and have probably rebuilt six or so. You will learn several tricks along the way. The 4 speed 930 trans are a piece of cake and MUCH easier than 915's.

Don't be intimidated. If I can do it, a 12 year old could probably figure it out.

Tinker

[moazam]

Here is a simplistic question...

If a novice (i.e., idiot such as myself) were to work with a friend who has worked on non-Porsche transmissions....how long will it take to rebuild a 915 transmission?

I'm hoping it can be done in 3 weekend...am I dreaming?

[magilla]

I "assisted" someone who has done several (many). It removed much of the mystery, and is relatively straightforward. Jsut make sure you are ORGANIZED. Lay everything out in order on the table and don't mix them around. With the engine already dropped and the tranny seperated and drained, it took us from 9 AM till about 5 PM to do it and reassemble. Without all of the instaruction and gawking time, it could have been done in 5 hours, easy. Plan on 1 day to drop and seperate, 1 day to rebuild, and 1 day to install. This is with a person to help, and if you don't run into problems. If you do, or don't have someone to help, then double or triple the time.

Worst case, you can bring the parts to someone and have them help you reassemble.

[red-beard]

Here's my rebuild article for the 901. The 915 isn't that much different, but you will need the exploded view diagram for the shafts.

How much will you save? I can rebuild a 901 in less than 6-8 hours, including cleaning the case. The parts to repair it cost me the same as they cost you and they are not cheap.

So I think you'll save around $500-600 if you do it yourself.

[RickM]

Question:
If I open up my trans how can I tell if stock gears were changed out for non-stock ratios. Are they stamped with this information?

[red-beard]

The gears are marked, but unless you have reliable information, I would say you have stock gears.

Gear swaps are very very expensive. Hmmmm. I think I need one more very in there....very very very expensive. And they are not a no brainer, like rebuilding the replacable parts.

Unless the car was raced competatively, I would say you have stock gears.

[echrisconnor]

Is there a good 915 rebuild article or page similar to Red Beard's 901 site (Thank you Red Beard -- great article!)?

[Zeke]

Put your gear stacks on opened up coat hangers and tie back together for washing the parts. Even with the exploded diagrams, it's hard to see which way a couple of things go if you get them disoriented. An old clutch disc is a great tool to hold/torque the driven shaft. You would put the disc in a big vise. I found my big (32mm?) deep socket at AutoZone for $6. Don't forget to mic the gaskets before throwing away. And mark the position of the shift forks carefully before disassembly unless that was part of your problem. I realigned my shift forks w/o the special tool, but it's a little guess work and a little luck plus some general mechanical aptitude to accomplish this part.

[red-beard]

Well, I'm going to open up a 915 shortly (In the next Month or So, after the wedding), so I'll publish an update to the article to cover the 915.

James

[moazam]

Originally posted by red-beard
Here's my rebuild article for the 901. The 915 isn't that much different, but you will need the exploded view diagram for the shafts.

Where is it? I don't see the article...missing link?

[red-beard]

sorry

http://home.san.rr.com/pb914/rebuild

James

[red-beard]

So....who wants a 915 rebuild article? Show of hands