gearbox repair time!

Ferraripete · Ferraripete's Garage

as several of you remember, i had a pretty big (sounding) incident w/ my gear box in a second to third upshift. well, i am finally going to have it trailered to the shop next week to see what the damage is.

i suspect at minimum, i am looking at having to replace the 3rd - 4th gear sets and additional hard parts associated.

my question is should i do a short gear replacement? what gears are replaced? 2nd, 3rd, and 4th? how about just 3rd and 4th?

how is driveability impacted? where do you get the gear sets? are there recommended ratios? what is the cost differential between the short gear versus the stock replacements?

this is not nor will it be a track car...it is too nice to beat up but it has been a very exciting street car. i have owned this car for many years and i have tastefully upgrading it during my ownership (no cosmetics other than zuffenhaus wheels). are short gears a great mod or will i regret it?

Thank you all for your help and guidance.

pcb

A930Rocket · 02-13-2011, 08:36 AM

Talk to Brian Keith Smith. He regeared his car and although he drove it on the track, he might still have some insight.

Ferraripete · Ferraripete's Garage

i have known brian for years but have not seen him for years likewise. do you have a contact number? does he still live next to the late benny parsons?

can you send me a p.m.?

thank you.

Peter

A930Rocket · 02-13-2011, 10:13 AM

PM sent.

Ferraripete · Ferraripete's Garage

thank you. i will call brian now.

best,

pcb

TDIDog · TDIDog's Garage

Hi FerrariPete, I regeared mine. 2nd,3rd, & 4th. Once you shift out of first it accelerates fast. Cruising speed is a little noisier. The ratios I went with are 2nd 1.55, 3rd 1.05, 4th .77, factory R&P at 4.22. I used a ratio calculator on computer to keep RPM at about 1500 drop between shifts @5000. 4th is slightly low, but all I could get. I looked at changing the R&P ratio as mine was shot, but it didn't change the spread between the gears. I am not an expert, but if you want more info let me know. I haven't driven the car in a couple of month, as it is put away for winter.

Ferraripete · Ferraripete's Garage

i spoke to brian and he indicated that he only regeared 3rd and 4th. he did not have the ratios committed to memory but he did indicate he wished the 3rd was a bit longer.

he was more concerned that the issues i have had w/ my gearbox were not resolved the first time i had the problem. now i have the very same repair to contend with w/ only 1k miles on the clock since the last repair. hmmm?

i worry the symptom was repaired and not the problem.

pcb

A930Rocket · 02-13-2011, 02:14 PM

Can you post a link to your old thread Pete?

Did you have it rebuilt once and then have to have it rebuilt/repair again? Now your on your third rebuild/repair? Who did the work the first two times? I'd be inclined to not take it back there unless it warranty work.

Yes, I think BKS is right. Sounds like someone just replaced the broken parts without looking at the underlying problem.

Ferraripete · Ferraripete's Garage

gear box repairs...short gears?

here is my old post. sorry if my new post is a bit of a rehashing. i should know better than to tie up additional bandwidth.

i appreciate the interest and help guys.

pcb

JFairman · 02-13-2011, 05:13 PM

In your origonal post you asked where to get gearsets for a 930 box.

If you go to ebay and do a search on "porsche 930 parts" you will find alot of gearsets for sale... first through fourth.
There's a couple ring and pinion sets too.

Seems the ones currently listed are mostly in Colorado and LA, and the prices are up there but alot of ebay prices are ridiculous and not set in stone.

When going through the ebay pages set it to 200 items per page view down at the bottom so you don't have to reload next pages as often.

Ferraripete · Ferraripete's Garage

i will look now. thank you for the advice. can anyone tell me the benefit of changing gears as opposed to ring and pinion?

930LDR · 06:19 PM

I went with shorter/closer 2, 3 and 4. Huge difference in acceleration. I've got the gearing charts and rpm drops on my blog (Blood, Sweat & Broken Gears). Mine is a track car. If I was more concerned about street driving I may have spent more time finding oem style cut gears as mine do whine a bit but I got used to it pretty fast. I also would have opted to shorten up first a tad rather than worrying about 4th. I bought mine all from Guard.

I have the excel spreadsheets that I can send you as well if you want to play around with your own mix of ratios.