915 3rd gear synchro

[NikosF]

I took my 83SC to a shop today hoping to get them to replace the shifter coupling bushings to improve my 915 (already swapped to Swepco 201) - they informed me my 3rd gear synchro is shot.

I'm a bit annoyed my PPI didn't pick this up - I've never had a 911 with a 915 before so when I test drove assumed it just have to be shifted carefully.

Am I damaging anything else by not getting this done soon?
What's involved in doing this?
Any ballparks on parts and labor hours?
What should I make sure they do once the tranny is apart?

Thanks!

[MARISOL78sc]

Just had mine totally redone after my 1st gear synchro bought the farm. It's not cheap as if your in there you might as well do it all and do it right. Here's a link to my thread http://forums.pelicanparts.com/porsche-911-technical-forum/907406-915-rebuild-advice.html

[sugarwood]

Can you describe what happens when you shift into 3rd?

[Reiver]

You couldn't tell the 3rd gear synchro was shot?
I doubt a PPI would pick it out if you couldn't 'feel' it yourself...it's not like they break the tranny down.
You can extend the life of that worn synchro by double clutching....I do that normally for fun even tho my box is refreshed. You can do that up and down but def when downshifting.
No, you won't hurt it any more than it already is basically...you can drive it until it fails to go into gear and then deal with it. Mine lost second gear but I could still use all of the others so it's not like you are stranded.
You probably have more than the one synchro / slider needing replacement too.

[Discseven]

Good syncro on left next to worn. Intelligent shop will advise replacing all syncros at same time. Worn syncros will still work but not as effectively. Best to shift into a worn syncro's gear slowly to compensate for syncro's wear.




Good dog teeth next to worn. If syncro is worn... good chance dogs for that gear are worn as well. Inspect all gear's dog teeth. Inspect all gears.

Engine and trans are dropped from engine. Gears are pulled from trans. Depending on what is found, time will vary. Rough estimate is 6 hours for trans work including engine/trans in and out of chassis. While engine is out, it's typical to attend a variety of other things given the accessibility of engine & trans so budgeting for this type of attention is always a challenge.... exactly how much should be attended?! Always a personal call.

[john walker's workshop]

Shift sleeve will wear also, where it rubs on the syncro mostly.

[NikosF]

Originally Posted by sugarwood

Can you describe what happens when you shift into 3rd?

It's not terrible - just a bit of resistance than on the other gears and a bit of a 'clunk' feeling when it slips in.

Originally Posted by Reiver

You couldn't tell the 3rd gear synchro was shot?
I doubt a PPI would pick it out if you couldn't 'feel' it yourself...it's not like they break the tranny down.

No - to be honest I couldn't. I've never had a car with a 915 before, and when you read comments on the boards and BaT - you get the impression a 915 is like shifting an old tractor - so I thought that was normal. None of the other 911s I test drove were fantastic in the shifting department.

I agree they can't pick up ever issue in a PPI, but I would have thought an experienced tech could feel it on a test drive

Thanks for all the other advice guys - I guess I'll drive it til it gets worse, heel-toeing in the interim, and start saving for a WEVO shift gate or something to do at the same time.

[sugarwood]

Here's one vote to scrape together the $2500 or whatever, and get it fixed. You're going to spend it eventually, so you might as well enjoy it.

[Trackrash]

A couple of things. I am assuming the shop drove the car?

Does it grind when cold going into third? Better when warmed up?

A weak synchro can go quite a while if you take it easy. Third gear is the weakest synchro in a 915.

If the synchro is "shot" IMO it either grinds every shift or you can't shift into the gear at all.

What did the drain plug look like when you changed the fluid?

My experience with Swepco is shifting improves when the trans is up to temp. Many will discourage the use of Swepco in a purely street driven car.

At any rate, if the trans has not ever been apart before you will most likely will have to have it done at some point in the future.

[Matt Monson]

Gordon has good points.

[juanbenae]

try a clutch adjustment and/or better yet a new clutch cable. they stretch and you don't note mileage. a new cable may buy you a few thousand miles or more of good shifting. if it's not grinding when spiritly upshifted you are prolly OK. for a while.

if a shop suggests major work that you've noticed no symptoms of look to see how many cars are out front waiting to be serviced.... if your's is it look much closer.

[NikosF]

Originally Posted by Trackrash

Does it grind when cold going into third? Better when warmed up?

A weak synchro can go quite a while if you take it easy. Third gear is the weakest synchro in a 915.

If the synchro is "shot" IMO it either grinds every shift or you can't shift into the gear at all.

What did the drain plug look like when you changed the fluid?

My experience with Swepco is shifting improves when the trans is up to temp. Many will discourage the use of Swepco in a purely street driven car.

At any rate, if the trans has not ever been apart before you will most likely will have to have it done at some point in the future.

Definitely better when warm. I don't think it is 'shot' - just on the way out. I remember when my Alfa's 2nd gear synchro was 'shot' - it was miserable. I'm definitely not at that stage.

Drain plug was mostly clean - a few tiny metal filings when I cleaned it. No 'chunks' of metal.

With 143k miles - I'm sure it is definitely in my future - perhaps a winter project - but good idea to get another shop's opinion.

Thanks for all the input. I'm a newbie to aircooled P-cars.