how hard are synchros to work on?

Eldorado · 11-13-2006, 07:40 AM

having very basic knowledge of the workings of the clutch or transmission on *any* car, I've got a question that may require a "dont even bother" response.. i dont know..

some of my synchros are worn out.. most notably when i shift from 2>1 at any speed, and from 3>4 fast.... or from 5>4 at any speed.

is it even worth bothering to fix? or should i just live with it?

Techno Duck · Techno Duck's Garage

Its my understanding that in order to change even just the synchros, it will require some specialized equipment such as a hydraulic press. There are a few threads (notably on Rennlist) that give a brief description of what needs to get done.

You can probably have them changed by a competent shop for roughly $700-1000.

Its my understanding its not exactly a job a home mechanic should try to undertake. But i bet with patience and the factory manual at your side you can probably figure out how to do it. To paraphrase one person though, read the factory shop manual on the transmission and it will probably scare you away from doing the job.

Personally its something i would let a professional do, even if i had basic knowledge.. there are alot of things to worry about like shims and spacers.

The best you can do is just double clutch whereever you get the common grinds. My 1st to 2nd though not terrible, is a pain in the butt sometimes having to wait for the synchro to catch up. I always double clutch that shift when the transmission is cold (it grinds all the time when cold).

I will say its weird to drive a rebuilt transmission, i drove my friends '88 Turbo less than 5k miles on the rebuilt transmission (new synchros on every gear). It was the first and only 944 i have driven that did not have the 1st to 2nd grind. Talk about smooth! If i decided to keep this car for the long run.. i would defenetley have the tranny rebuilt and a LSD put in while it was apart. but thats about $1500 right there!

mlue · 11-13-2006, 08:14 AM

Kyle, have you changed the Transmiision gear oil yet?

Eldorado · 11-13-2006, 01:51 PM

oh yea the gear oil was replaced with 80w90 synthetic... much better after that.. but still not the greatest..
you cant push it into 1st even if you're doing 10kph..

i dont have the 1>2 grind, but it does grind (badly) from 2>1.

i guess i'll just live with stopping in 2nd, and down-shifting from 5th to 4th by going through 3rd first..

my transmission already has an LSD...
there are a couple transmission shops around.. i guess i can go in and ask them.. as well as the local porsche shop, just for reference.

thanks techno.. anyone else have any differing advice?

Ferrara_racing · 11-13-2006, 01:57 PM

I'd budget more than 700 clams, my 944 clutch job was 2K. There is a lot of disassembly needed to get to the promised land on the 944. Speaking of clutches , I'd throw a new one in if you have the syncro's done..

Techno Duck · Techno Duck's Garage

Removing the transmission is only about 1/4 of the 'hard part' to a clutch job. The rest of it is taking off the rusted exhaust bolts, speed and reference sensors, moving back the torque tube..getting the clutch pivot pin out an.....etc.

Eldorado · 11-13-2006, 02:11 PM

maybe for it's 30th birthday, if i even have it that long (odds are not in that favour, but you never know)... to celebrate it becoming a "historical vehicle", I'll give the transmission an overhaul and a nice sparkly new paint job.... lol

jcommin · jcommin's Garage

I agree with Techno Duck, don't try this at home.

VINMAN · 11-13-2006, 04:55 PM

I changed all of mine, then again I have a press , gear pullers,etc...
Honestly wasnt that tough of a job.

Eldorado · 11-13-2006, 05:06 PM

wanna fly up and do mine, vinny?

it'd be cheaper than having a shop do it! lol

VINMAN · 11-13-2006, 05:42 PM

Good excuse to get away for the weekend!

Zero10 · 11-13-2006, 06:41 PM

If 80W90 made it better, then try Redline MTL.
Almost completely cured my grinding gears problem, and it was pretty bad.

Eldorado · 11-13-2006, 06:56 PM

hmm... i'll consider that actually.. might as well...

91S2 · 11-13-2006, 07:13 PM

having my synchros done right now along with the clutch... and then some. i was contemplating if i made a smart decision going to my mechanic. glad to hear most of you agree this isn't the typical DIY. although, definately Not too anxious to get that bill

Techno Duck · Techno Duck's Garage

91S2, who are you using to rebuild your tranny? And if you dont mind me asking, how much is it costing you total (parts and labor). You can PM me if you prefer..and i understand if you care not to divulge.

Also where on LI are you? I am in the Oyster Bay area.

91S2 · 11-13-2006, 07:58 PM

pm sent

hpaulb · 11-14-2006, 06:37 AM

There is always the rout of a used tranny if you can trust the source. I can help guide you through the romoval. I'm going through it with Dan now.

AFJuvat · 11-14-2006, 01:10 PM

It isn't all that hard. You will definately need a press and some gear pullers. They key is knowing exactly what you are looking at and taking good notes as to where everything goes.

AFJ

Eldorado · 11-14-2006, 01:53 PM

afj, how long would you say the job would take realistically? and what is the book value?

Zero10 · 11-15-2006, 08:40 AM

IMO the key is getting all of the adjustments correct. Set the lash on the R&P incorrectly and that is the end of a now good transmission.
If I had a really good manual to rebuilding one I would give it a shot, otherwise I would only trust a qualified transmission shop (a.k.a. not one of the ones I've ever been to!).