Difference between 915 and G50 rebuild?

[yelcab1]

I did several 915 gearboxes and other than a few fairly non-expensive special tools, not much else is needed. I might be looking at a 993 G50 gearbox rebuild soon. So...

1. What are other special tools that might be needed?
2. How much more expensive G50 parts are?
3. How much experience can be carried over from the 915 to the G50
4. Should I do this or just send the box to someone?

[dannobee]

1. Something to heat the bearings and synchro sleeves.
2. Depends on what it needs when you get inside. Gears can get pricey.
3. Other than being a transmission, about the only thing similar is setting up the ring and pinion.
4. If you can already rebuild a transmission, a G50 is similar to any other modern transmission.

https://forums.pelicanparts.com/porsche-911-technical-forum/1157509-guy-his-garage-attempts-rebuild-g50.html

[john walker's workshop]

An electric frypan for the german soup and a $500 long arm puller. Don't slide the shift sleeves off the hubs or the springs, balls and clips will go all over the place and might go missing.

[Jsbarrie]

915 is about 5k to rebuild

[Matt Monson]

Expect parts to run 2-3 times as much. $200-500 synchros and $800-1000 shift sleeves.

[yelcab1]

So summary:

1. Something to heat bearings and sleeves. Checked. Have an oxy torch.
2. Gears are 2-3 times more than 915s. Checked. Have a bank account.
3. Electric frying pan. Checked. Have a propane portable camper cook top.
4. Don't slide the shift sleeves off the hubs. Checked. Will do it inside a plastic bag.
5. A $500 long arm puller. That is the only tool I need to buy then.

OK, would $10,000 do this job?

[dannobee]

Whoa, that's plenty if you're doing it yourself.

Use the kitchen oven for heat. Oxy-acetylene torch is overkill.

A thorough and unbiased test drive to determine which gear(s) are giving problems. And note any unusual noises from the trans. If it's tough for you to discern noisy from normal, have someone with some experience test drive it for you. There are plenty of people in the bay area that can help in that regard.

[jess p]

Well, I don’t have a G50 but I’m building some 915’s. In the past I’ve built a couple of trans for my 914’s and apparently I must have got the pinion depth ok. Wish I had a G50.

Currently I’m building an early 915 7:31 mag case, all new bearing, synchros etc. I’m also
building a 83 915 case with all new bearings, synchros, dog teeth etc.

JS Barrie is correct, it’s about 5 grand. Now, my big question, without that fancy vw tool
how do I do accurate pinion depth etc.

Thanks

82 911 SC
76 911 S
67 912
70 914
22 C8
01 C5
916 Ducati

[Matt Monson]

Shop rate to rebuild your g50 for you is generally $8-10k.

RMG, just south of you, was sold to Bob Grigby’s employees when he retired. He’s still “on call” with them for gearbox services. If you have any doubt about doing it yourself, this is the local way to go. Zero reason to ship to a specialist out of state.

[yelcab1]

So, $5K for parts with free labor is good for a G50 Rebuild? I have zero doubt about doing it myself, I just need to get the right tools.

The 996/997 gearboxes require a 50 ton press to rebuild. That is a bit harder to come by. If the only thing needed for a 993 G50 is an 18 inch long reach puller, that is acceptable.

[Matt Monson]

The press thing is only true for Carreras. All Mezger powered cars (GT series and turbo) are G50 derivatives. They are basically cable shift 993 gearboxes, with some changes. But the gears are splined, and not press fit.

[yelcab1]

From reading the other post referenced above (...guy-his-garage...), it looks like a long reach puller of up to 10 inch reach is enough. Is that so?

And a hot plate, as well as some tongs to pick up the hot parts are good ideas.

[john walker's workshop]

Got this 16" unit from Snapon, hence the price. Any shorter wouldn't work.

[dannobee]

You can either buy the long jaw puller than John posted, or get a Harbor Freight bearing puller set and some all-thread to lengthen the pull. One of the factory special tools I had at work we lovingly called "the erector set" that was just a high end version bearing puller set with 1/2" all-thread. Might have been for Tremec transmissions. It worked fabulous on G50's.

You'll also need some sort of bearing puller for the differential bearings.

If you have a pair of welding gloves, they'll work better than the tongs. Get the parts hot and they literally fall in place without pressing.

[AlBackus36]

You'll need something 2 or 3 inches longer than the HF master kit I got if you want to get into 3rd and 4th, but the rest of the box is doable with that kit alone. From pretty rough memory I would budget 1200 per slider, 1000 per gear w/dogs, and 200 per syncro block. That doesn't include bearings. Bearings were all over the place. 100-400/ea. I was able to find most parts through help from Matt Monson and some basic googling from the usual sources.

[yelcab1]

Dan, I have a basic Cheap-ass bearing puller set. I can find some all threads to extend the reach.
John, I'll cruise ebay to see if I can score a used 16 inch puller. Good to have tools.
And I have welding gloves so no need for tongs.
Al, I need to get into 4th gear, so the longer reach is required.

[yelcab1]

This 13 ton, 11 inch reach, 3 arm puller. Will that suffice for 3/4 gear?

[AlBackus36]

Yel,

The HF kit is 12 inches long, so nope. I think you need what John is recommending, or what Dan has recommended combining a bearing splitter kit with all thread. I remember needing 2 or 3 inches longer than the HF kit.

https://www.harborfreight.com/long-jaw-master-puller-set-22-piece-58003.html

[yelcab1]

Alright, I'll look for a 16 inch reach puller.