915 Transmission Rebuild

[Boko2011]

Well it looks like the transmission in the 77 is starting to go!! Starting to look at rebuild options and wondering is this something that i want to tackle on my own?
What literature would be the best route to follow?

Another route would be me taking the transmission out and it being rebuilt by someone else... What would be the ballpark cost of getting it done?

I am decent when it comes to wrenching around a motor... I know how the motor works but i am somewhat oblivious as to how a transmission works... That is the main part that scares me about trying it myself... What would you do?

[callard]

Read Pete Zimmerman's bible on the 915. It will tell you what to do and you decide if you can do it.

[sjf911]

It depends on what you define as a rebuild. Simply replacing dog teeth and synchro hardware is relatively easy for 5th, 1st, and 2nd gears. 3rd and 4th require disassembly of the main shaft which necessitates sourcing or fabrication of special tools. Replacing the bearings is relatively straight forward except the rear most pinion shaft bearing. Mess with the ring and pinion preload or depth and you have to have serious tools, shim selection, and a lot of patience.

[Boko2011]

Well I guess to be more specific it grinds when going into first gear and pops out of third if you let off of the accelerator. How much do you think it would cost for me to take it somewhere?

[Peter Zimmermann]

Originally Posted by Boko2011

Well I guess to be more specific it grinds when going into first gear and pops out of third if you let off of the accelerator. How much do you think it would cost for me to take it somewhere?

How many miles on your trans? Any past repair history?

Trans have an aluminum or magnesium housing?

Where are you located?

[Andy911sc]

Peter Zimmermann,

I know you have the website with the complete rebuild of the 915 transmission, but did you ever make a book to sell? I don't always have access to a computer out in my shop, so a book would be helpful.

[Peter Zimmermann]

Originally Posted by Andy911sc

Peter Zimmermann,

I know you have the website with the complete rebuild of the 915 transmission, but did you ever make a book to sell? I don't always have access to a computer out in my shop, so a book would be helpful.

Unfortunately, when we ran the numbers to print/publish a trans repair book, or a magazine format, the project, on a professional level, just wasn't feasible. My best suggestion is to print the Tutorial and put the pages in a 3-ring binder. Sorry!

[Flat6Heaven]

As undoubtedly many others, that is exactly what I've done. And it is of immense use, THANKS!!
But an even more detailed version, in print à la "101 Projects" would surely sell... I'd buy at least one!

[Walko]

Sorry to hijack the thread but how often do the sliders themselves wear out.

My box is apart after having a rebuild six months ago ( not by the best mechanic is seems)

The new mechanic is saying the sliders and bearings are worn out. I'm not doubting him but the box shifted beautifully before coming out. Im just curious as to how much wear the sliders and shift forks can have on them before they need to be replaced.

It only came out due to shorten the gear stack.

Michael

[Peter Zimmermann]

Originally Posted by Walko

Sorry to hijack the thread but how often do the sliders themselves wear out.

My box is apart after having a rebuild six months ago ( not by the best mechanic is seems)

The new mechanic is saying the sliders and bearings are worn out. I'm not doubting him but the box shifted beautifully before coming out. Im just curious as to how much wear the sliders and shift forks can have on them before they need to be replaced.

It only came out due to shorten the gear stack.

Michael

Do you have a documented parts list for the repair done six months ago? If the sliders were replaced then, and are truly "worn out," it would only be because of the most abusive, unskilled driving one could ever imagine, and the dog teeth that mate with the "worn out" sliders would also be "worn out".

Sliders are normally only replaced at the same time synchro rings are replaced. They wear together, they should be replaced together.

What are your technician's reasons for declaring that the sliders & bearings are worn out? Shifting well, and a lack of noise, seem to point in the opposite direction...

[Walko]

Peter,

Lots of noise but this was from ring and pinion not having correct backlash.

Shifting fine.

I'll dig out the list of parts bought.


Michael

[maui44]

Peter "Z" is the man regarding 915's.

I had my completely rebuilt (By a very good shop in San Diego) several years back and it was about $3400. The labor alone was $1,331.
It you have the working knowledge, you can save some money doing it yourself.

[Walko]

No intentions of doing this myself I have a mechanic I trust now.

Michael