930 1st Engine Drop & Trans R&R

[b5aar]

Kind of looks like mine......Stage 1....tough to say for sure though.....

[911tracker85]

great thread and perfect timing.

once I finish installing the new clutch in my 951 track/DE car, this will be the first thing I do to begin my refresh of my 78 930 clone.

I'll be following your progress.

[MikeD930]

I dismantled the transmission today. The toughest part was figuring out how to lock the gears in order to remove the pinion and drive shaft nuts. Normally a special tool or modified clutch disc locked down at the bell housing shaft is used but I have neither and did not want to "damage" the removed clutch disc. I've read somewhere you could engage both two gears at same time but I did not want to risk damage not knowing whether this would work or not. Final option is to use idler reverse gear with gearbox in 4th gear. Apparently the shaft for idler reverse gear is pressed fit into the removed front cover which I did not want to mess with. One could make a custom shaft (one end is smaller than the main shaft) using a lathe. Again I don't have a lathe and didn't want to spend more time designing and subcontracting out machining. So I was able to place and hold the idler reverse gear by hand (depend on which nut is being removed determine which side the idler gear is placed on) and loosened the nuts (with trans set in 4th gear) using an impact wrench. Take your own risk if you want to use my method!

Front cover removed. Note idler shaft being part of front cover.




Below are the tricks I used to loosen the shaft nuts. These photos were taken after this was accomplished.

Placement of idler reverse gear for removing the pinion shaft nut (large reverse gear). Gearbox is upside down.




Placement of idler reverse gear for removing the input/drive shaft nut (small reverse gear). Gearbox is upside down.




Removed large reverse gear. Gearbox right side up.




Center case removed.




Checked for selector rods lined up...Checked good.




I found that 1st/2nd gear fork was not centered! Its gear selector rod is centered within the detent. No wonder why 2nd gear syncros would grind easily if I'm not patient and firm when shifting into 2nd gear especially during downshifting.






3rd/4th gear fork is fairly centered.





continue...

[MikeD930]

Removed gearbox assembly on bench in order of each component removed (beginning shown on right to left of photo).




Close up photo of 1st gear syncro. Dog teeth are not too worn. Syncro ring looks half worn.




Close up photo of 2nd gear syncro. Excessive wear on dog teeth. Look how rounded they are! Syncro ring looks half worn.




Close up photo of 3rd gear syncro. Some wear on dog teeth (beginning signs of hooked teeth). Syncro ring looks half worn. Note chipped/missing surface. I'm not sure if this was defective since new.




Close up photo of 4th gear syncro. Same condition as 3rd gear syncro. Syncro ring has some wear.




Close up photo of 1st/2nd slider.




Close up photo of 3rd/4th slider.




This is where I'm at for now. I will be dismantling each gear syncros over the next few days. Hopefully, I don't expect to see anything wrong. Looks like I'll need to replace all syncro parts (syncro rings, sliders and syncro hubs). I would like to skip replacing 3rd/4th gear slider and syncro hub (at least replace syncro rings). But I suppose it's best to replace everything and not worry about opening the gearbox again.

[quattrorunner]

Great photos.

[Miguel Antonett]

I'm a believer... Good job Mike!!!

[MikeD930]

^^^Hey thanks guys.

Quatto...hope the photos of how the gear selector forks were lined up help you out. The 1st/2nd gear selector fork was off!!!

[krasuskyp]

Excellent work / descriptions / photos, MikeD! Very helpful, well done.

How "hard / complicated" would you rate this overall? Any special tools / expertise required, or just basic mechanical acumen?

Any projected cost guesstimation of what you'll be looking at for those intended bits?

Any idea what route yer goin for clutch yet?

Again, I am verrrrrrry closely watchin you here... while I don't at all exactly relish the thought of droppin my drivetrain again, I'm somewhat actually considering it pending your results here.

Slippyish clutch / grindyish box somewhat temper driving enjoyment certainly...

[MikeD930]

Paul...I'd say the effort to disassemble the gearbox is easy to medium. No special tools were needed up to this point. I used 1/2" drive impact wrench with 30mm and 36mm impact sockets to loosen the shaft nuts. In my case a gear puller was not even needed to pull the gears/bearings (after removing the center case). Just make note of how everything was taken apart and place each removed parts in chronological order in area where no one (i.e. kids and curious adults) can mess with.

I figure it would cost around $2k just for the sycros parts and $1.5k for the clutch kit (KEP stage 1 w/Kevlar disc). But am looking into having my KEP clutch rebuilt. Plus I'm also looking into changing the gearing. It currently has short 2nd-4th gears and I want to make the gearing taller.

Here's a pic of my gearbox after removing all gears and components. Note there's no need to remove the shafts since its R&P, bearings and seals does not need to be addressed.

[Ronnie's.930]

Originally Posted by krasuskyp

... while I don't at all exactly relish the thought of droppin my drivetrain again, I'm somewhat actually considering it pending your results here.

Paul if you do decide to R&R your GEARBOX resist the temptation to glue these offending bits, from your last year's thread, back in place (No JB Weld, but on second thought, maybe blue RVT will do ya' right, though?)!



Mike, again well done!

[krasuskyp]

eeeek - still $3k and DIY

awesome

thanks fer the feedback, tho - very helpful and insightful

Yeah Ronnie... I'm gonna fersuredly RTVWeld the busted gearbox oil pump hose nozzle grabber ear into my transmission. Einstein.

The displaced synchro toof, on the otherhand...........

[Ronnie's.930]

Originally Posted by krasuskyp

Einstein.

[krasuskyp]

^bwhahahaa^

man, those just keep getting more betterer!

[Matt Monson]

Got your pm but am traveling and cannot reply on my damn iPhone. Will get to you tomorrow.

-Matt

[MikeD930]

Matt...hey no problem. Looking forward to hear from you.


Paul...looks like your polishing tool is imitating Einstein.

[krasuskyp]

heh, that's funny MikeD! We both got kittens ~ same time then, eh? Great shot.

Mine typically sprawl across my keyboard while I'm trying to work... PITA.

I found my pair weren't particularly helpful in fixing my gearbox - either must only be good for affixing roofs to cabs, or I didn't use enough JBWeld / RTV?

[MikeD930]

Hmm...I should have noted that I "stole" the pic from google. BTW, when I was a kid we had a female cat that would have litters which we gave away when they were old enuf. Fun times!

[quattrorunner]

Sorry haven't had a chance to comment on the photos much but they're very helpful and informative.
I'm not as fluid and smart as mikeD. I have finally figured out that voodo magic crap inside that gearbox. I don't really feel smarter because of it though. It took too much trial and error for me to feel like I'm smart. But yeah, mine is in forward motion too.

[gsxrken]

Nice work, Mike and great photos.
I still think gearboxes look like the inside of a Romulan ship.

[JFairman]

Only transmission I ever rebuilt was a BMW 2002 4 speed.. many years ago. It's a Getrag 4 speed gearbox with simple brass Borg Warner synchro rings.
When taking all the gears, bearings, shims, and synchro units off the main shaft I put them on a straightened out coat hanger to keep them in order. An old broom handle or dowel rod works good too.
Then I cleaned them with mineral spirits in one of those throw away heavy duty aluminum baking trays you get at grocery stores.

I've never done a 930 gearbox. Mine was completely rebuilt by the previous owners mechanic and it works great.
I always blip the throttle to match revs and double clutch on down shifts so the synchros are hardly used and they will probably last forever while I have the car.
If going quickly and braking while approaching a corner I heel and toe the brake and gas peddle while double clutching.
It's fun and down shifts are perfectly smooth that way.