BC

Thanks.

DFWX

A bit different question - how hard is it to just replace sychros?
(I figure to try - if I do - on a trans out of a parts car I have.
What would be a reasonable price for a shop to charge to do this - if I provide the parts and the transmission out of the car?
Mark

BC

Thats a good question Mark. I'm all ears. It seems Jim has said that many times if the synchros are bad, so are some sliders and gears.

jyoon

you need to remove all the shift bars, shift selectors and the diff to get the top shaft out that holds the gears and synchros. this stuff is all fairly simple to do. you will need a slide hammer that you can rent from the local parts store. then you need the press to get the gears and synchros off. reassembly is a little more difficult.

i think this would take a shop around 3-5 hours to remove and reassemble. getiing the tranny out is the hard part.

BC

Really? I was thinking that was the easiest. 6 or so bolts, and boom, the trans drops out. Maybe 10 bolts. You get it low enough to take the TT/Trans bolts out. Then the CV joints.

jyoon

if you haven't dropped your tranny before, the shop manuals are a little out of order. the first step should be to remove the half shafts. if you follow the order in the manual, you have no way of preventing the tranny from moving while loosening the half shaft bolts.

hacker-pschorr

Don't you have to drop the rear suspension brace that goes under the trannie?

While the trannie is out, damn good time to upgrade the rear sway bar.

928ntslow

Actually, you can sit in on Greg Browns tech session as he will be discussing Transmissions this year at Sharktoberfest.

Stig- seriously, did they try to sell you some swamp land with that line? If you pull the converter, this is what it looks like behind it...you are looking at the pump housing. Go back and kick that guy in the crotch!




Behind the pump housing is this..

BC

True.

mpesik

[QUOTE=928ntslow]Stig- Go back and kick that guy in the crotch!

SteveG

It's just Stig . . . no worries.

Vilhuer

I haven't opened '78-84 manual box more than just to take a look inside. Wasn't pretty when four small diff gears were in pieces. '85-95 is little different and possibly little bit easier since syncros are one piece rings. Anyway, if I had a choice between doing engine and gearbox rebuilds gearbox would win easily. There's nothing really difficult to it. Automatic gearbox is different animal. I'd like to open one of those some day just to learn what it looks inside but can't give any promisees of geting it back together ever again.

BrianG

Actually, that might not be too far off........ WIth the GM TH series of auto-box, if you remove the pump-body, pretty much all of the drive parts pull straight out the front. When I was first taught the TH series on a TH 700R4, the teacher did exactly that. He pulled the pump and turned the housing vertically, and the innards pretty much fell onto the bench. He wasn't much of a teacher.

DFWX

While probably other things are wrong in any trans with over 100K and synchros out, it would seem better to replace the synchros to prevent further damage - than to do nothing for lack of funding to rebuild the whole thing. Given the cost of gears, I could probably buy a whole car for little more, if not less - or just buy used transmissions and keep gear jamming as long as each one lasts...
I am increasingly being convinced that for serious performance work, the 928 drivetrain has got to go and a conversion done to something stronger and more affordable to upkeep/modify.
I won't pretend that I could rebuilt a transmission.

For something completely different... is there a manner to change a LSD to a true locked posi-unit? Obviously that would be drag racing trans set up...
While transmissions are a bit time consuming to remove, expereince could reduce the time substantially and probably a few quick-remove elements added.

It seems that with 928s the real obsticle for radical performance is the transmission - which was a no brainer for American V8s - just buy the trans and differential/rear end you need - and cheaply if used. Even pro set ups used are cheap. I have about decided that at some point in the ongoing super 928 project I'll have to sanc the Porsche drive train (trans and diffential) and fab in USA stuff. Oh well.
Mark
DFWX

Newbie928

Does anyone have a tutorial on replacing just the synchros?