930 Gearbox Disassembly

[SteveBuchanan]

Does anyone know a good way to break loose each of the nuts at end of the two shafts? They are torqued on very tightly. Is it safe to use a breaker bar on each to get the necessary leverage? Would an impact wrench be better than breaker bar? Here is a picture of the problem.

[YTNUKLR]

I use an impact wrench to remove them...never damaged anything that way.

[SteveBuchanan]

Thanks. Is there a good way to keep the shafts from spinning?

[YTNUKLR]

I use an old clutch disc, and I have a "clutch disc lock" that is just a plate, that is studded into the clutch, and through the engine/transmission mount holes. It's like a flywheel lock and works flawlessly.

[David]

Steve, I'm contemplating changing some gears in my 930 box. How difficult has it been for you? I figure I could send it to a shop to have them change to a lower geared R&P or I could change out some of the gears myself. Are there any critical shims or settings that need to be set when it goes back together? Can you leave the R&P intact and just change the gears? Thanks.

[ChrisBennet]

Originally posted by 125shifter
Steve, I'm contemplating changing some gears in my 930 box. How difficult has it been for you? I figure I could send it to a shop to have them change to a lower geared R&P or I could change out some of the gears myself. Are there any critical shims or settings that need to be set when it goes back together? Can you leave the R&P intact and just change the gears? Thanks.

Changing the gears in a 930 trans is dead easy. You don't even need a press, just a gear puller with long arms. Possibly not even that. Removing the dog teeth from a gear is a pain for 2nd and easy for the other gears if you have the special tools and a press. If you are getting new gears or used gears with the dog teeth already removed you can install new dog teeth without special tools (but you'll still need a press).
I'd advise you to have a shop set up the R&P.
-Chris

[9dreizig]

Hey Chris, after our conversation on Sat regarding the same subject. I saw there is a tool for $125 if I recall specifically for the dog teeth on 1st and 2nd gear.. Would that make it a simple ( relatively) task? Seems we'd blow that much having a shop do it..
Todd

[ChrisBennet]

Originally posted by 9dreizig
Hey Chris, after our conversation on Sat regarding the same subject. I saw there is a tool for $125 if I recall specifically for the dog teeth on 1st and 2nd gear.. Would that make it a simple ( relatively) task? Seems we'd blow that much having a shop do it..
Todd

The "tool" only works for 1st on 930, at least with the stock 2nd gear.
-Chris

[SteveBuchanan]

Hi David,
I'm not sure how difficult it is yet, but I think Chris' description of the process is accurate. Once the tranny is out it should go smoothly. I have a unique tool that will make reassembly and shift fork adjustment more accurate. I found a case where the guy milled out the side of it, thus exposing the shift forks and the entire gear set. I will post a picture of it tonight. It is in place of the shift fork alignment jig which is difficult to find for the 930. I think many guys do the job without jig or the cutout case. Since this is my first time working on a tranny I need all the help I can get.

[Walt Fricke]

Other than being dimensionally different, the 930 is pretty much like the 915. The shift fork alignmnent "tool" is just a flat plate with some holes in it. The holes are for the various shafts and rods that go through the end of the main case, so they simulate the case being in place.

The idea of a dummy full case piece is intriguing (a use for a case somehow damaged?), but seems overkill. You can, indeed, usually get by without this tool at all, because the shafts and rods are held firmly enough by their bearings/bushings located in the bulkhead between the gears and the ring and pinion, so they keep their alignment even when unsupported.

However, it should be pretty easy to make this tool out of a piece of wood. Use paper to trace where these openings are (some ingenuity required) and drill suitably sized holes in your wood piece.

Naturally, if you have some kind of tool available, why bother making one.

Walt Fricke

(who used the worn out clutch trick to hold the input shaft, then eventually disassembled a rubber centered clutch to get the splined part to weld onto some scrap steel and bolts to duplicate the factory shaft holder)

[9dreizig]

Walter,
What's your experience with removing the dog teeth from 2nd gear.
Irrationally Exuberant Chris say's it's all but impossible ( or expensive !! or both).

[9dreizig]

Chris,
http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=911M&section=TRANSM&page=2&bookmark=4&part_number=PEL-TOL-P224
This clearly says 1st AND 2nd gear.. so who's right ?? you or Pelican??

[David]

Anyone have a picture of the dog teeth tool? I can usually make any tools I need at work.

[ChrisBennet]

Originally posted by 9dreizig
Walter,
What's your experience with removing the dog teeth from 2nd gear.
Irrationally Exuberant Chris say's it's all but impossible ( or expensive !! or both).

It's not impossible, it's just that it's much harder than the other gears because the synchro hub removal tool doesn't work for 2nd. Perhaps there are some 930 2nd gears that have larger diameters so the tool would work with those? That's off my map of experience though.
BTW: My friend Palmer cuts off the 2nd gear dog teeth with his milling machine for me. It's good to have friends.
-Chris

[ChrisBennet]

Originally posted by 125shifter
Anyone have a picture of the dog teeth tool? I can usually make any tools I need at work.

SIR Tools makes the ones I have. Here is the one for "1st and 2nd" gear (that really only works for 1st):


-Chris

[Walt Fricke]

9D

For the 915 tranny you need two dog teeth removal tools. The dog teeth have different IDs and ODs depending on the gear, but two covers the lot. Sounds like maybe the 930 second gear is an "oddball" for which the proper tool is not available? At least not at a reasonable price for DIY?

Milling the old out sounds fine - I have heard of people using a cutoff wheel on a Dremel to do much the same thing - break the compression forces so you can push the old off. As I recall, a less precise improvised tool can be used to press the new ring on.

But having the right tools sure is nice.

Walt Fricke

[SteveBuchanan]

Here is a picture of the cutout case.

[David]

Thanks for the pic Chris. After thinking about my gearing for weeks: R&P, change gears, or G50? I've decide to do nothing. I figure I'm making a big change with the engine and EFI so I might as well see where the power band is before I go and make gearing changes.

[ChrisBennet]

Originally posted by 125shifter
Thanks for the pic Chris. After thinking about my gearing for weeks: R&P, change gears, or G50? I've decide to do nothing. I figure I'm making a big change with the engine and EFI so I might as well see where the power band is before I go and make gearing changes.

Wouldn't hurt to replace or at least flip some synchros and stone the burrs off the sliders. Don't need any fancy tools and the paper gaskets probably cost under $5 I bet. (The 3 for a 915 are about $1 each.)
-Chris

[David]

The tranny was shifting good when I pulled the engine. Another reason not to go into it is that this project is way over schedule so I'm trying to cut the scope back. With everything fresh and clean it should be easy to pull the engine and tranny and change gears a couple months after I get it running.