G50 syncro lifespan?

[chrisbruck]

For a predominantly street driven G50, any ideas on typical mileage to expect out of the stock syncros, particularly 2nd and 3rd?

Mine's got 156k and 2nd is starting to get "crunchy" especially when cold. Barring any ham fisted shifts, when do most start rebuilding these? Mine's still good you just need to take it easy going to 2nd. Just curious....

Or perhaps I just need to drive a 915 for a while then my G50 will feel smooth as silk again!

[Lyle O]

Funny you mention about going into second; mine is also a little clunky, but only when cold (first few shifts, really). I've got 112K on the clock. Once the car is nice and warm, all is smooooth. FWIW, I put Redline 75-90 synthetic in last summer, and there was an improvement.

[Jesse16]

Mine has about 220K and maybe 14 DE weekends. First and more so second are a bit crunchy when cold also, budgeting a rebuild maybe next winter. Will do a fluid change this spring sometime and try to really notice if any improvement. Been 3 years and 30K or so since last fluid change.

[Hnichols]

Would synchro wear manifest itself first when cold? Or would stiffer cold shifts be due to another problem? I would think that temperature wouldn't make a huge difference, but I really don't know.

[KTL]

The synchros can go for years and years w/out rebuilding, even if crunchy. They're not like the 915 which can eventually let go of the synchro pieces that then cau$e collateral damage to your tran$

Mine has 83K on it and has been crunchy going into 2nd when cold for a long long time. Usually takes only a few shifts for it to get better. I've tried all sorts of gear oils and none have struck me as being leaps and bounds better than the others. Mobil 1 from local parts store, Mobil 1 SHC/Delvac, Redline, Swepco, Valvoline HP dino. All seem about the same to me. I currently use the Valvoline in the white bottle and it works fine.

I noticed in the past few years of track driving that the 3rd gear upshift and 2nd gear downshift would crunch as the temps got hot. The way I "fixed" that is to double-clutch on the downshifts and be more patient/gentle on the 3rd upshift.

[chrisbruck]

Sounds like mine is on par for pretty much normal then.... not a huge deal, I just take it easy going into 2nd.

Plus it's more "clunky" than "crunchy" so I'm not too worried about breaking anything in there. I may swap out the Kendall fluid for Mobil 1 or something similar to see if it helps any.

[pavegeno]

135K on the clock. I take my time between all the gears, especially 1st to 2nd and 2nd to 3rd. When cold, it's a little stiffer. From 1st to 2nd I get what I'd call a slight "nick" feel from 1-2 and 2-3. Never a metallic sound or feel, just something. Been that way since I bought it at 67K miles. No better, no worse.

Would be great to understand better indications of when a rebuild is necessary or indicated.

[Josh D]

Originally Posted by chrisbruck

Or perhaps I just need to drive a 915 for a while, then I'll know what I'm missing!

Fixed it for ya!

[awhnry]

My suggestion is to never use the transmission for a downshift. It is really totally unnecessary for modern cars with good brakes. Even on the track, the downshift should be the last motion as you release the brakes and turn into the corner so that the trans is in the right gear for the corner. Anything more than that is purely just ego.

[KTL]

I think you mean never use the transmission for engine braking? Agreed, brakes are much easier and cheaper to service than clutch/transmissions and/or engine rebuild.

To further awhnry's point, I think its a waste of coordination and clutch operation to sequentially change down gears under braking. For example, going from a long straight to a slow corner I go right from 5th to 2nd at the end of the braking zone instead of going 5-4-3-2. Easier to match revs/heel-toe at lower rpms as well, IMO.

[alfisti]

My '87 has 226k miles on it. I wasn't told the gearbox had been rebuilt - but it shifts surprisingly well. I only get a slight "nick" (well said, pavegeno) on the 2-3 shift. Compared to the Alfa Romeos I had, this is downright miraculous. Still a joy to shift.

Thanks
-Glenn

[gamin]

Mine is a little crunchy into second when cold. Smooth when warm. Looks like the norm. 103K miles.

[chrisbruck]

Quote:
Originally Posted by chrisbruck View Post

"Or perhaps I just need to drive a 915 for a while, then I'll know what I'm missing!"

Originally Posted by Josh D

Fixed it for ya!

THANKS!! What was I possibly thinking...

[Chuck.H]

Luckily my G50 shifts the same as when I got it over 20 years ago (I'm basically the original owner, it was pretty low miles when I got it). Never crunchy, but it has the same cold-start notchiness in first and second gears as it had when 'new'.

I will say that I have always shifted extremely gentle, using a very light touch on the shifter and matching revs on downshifts as best as possible.

On a related note, I rarely use first gear once it's warm, I just startup in second gear. Avoids the upshift, and it pulls great off the line in second gear with almost no slipping of the clutch.

Chuck.H
'89 TurboLookTarga, 371k miles

[Matt Monson]

Downshifting and loading the gearbox on track is NOT 100% about ego. It has its place in high performance driving, but like anything it's all about doing it in the right place at the right time in the right amount.

There's a turn at my local racetrack. It's a wide 180+ degree turn that transitions from entering on a fast downhill to existing climbing a hill.

If one trail brakes into it in 3rd (as my car is geared) and drops it to 2nd just as you apex, it wags the tail barely, locks the LSD, and you launch up the hill with the throttle to the floor.

I know guys who downshift to 2nd later in that turn and complain about how they push out to track out and have to lift because they aren't rotated enough.

But that's at the track. On the street, downshifting and using the tranny to decel is just to feel cool and because the engine sounds neat. That's ego.

I personally prefer avoiding absolutes when we start talking racecraft. There is usually at least one example that can be found to challenge the "all the time" claims.

[awhnry]

Yes, I appreciate the correction. My post makes more sense with your addition.
And yes, there are always exceptions to the general rules but again with modern automobiles, use the brakes not the trans to slow the vehicle on the street. And dont shift into first gear when the car is moving. On the racetrack, there will be exceptions just because you are trying to make pigs fly and deal with the car as it is rather than a perfect situation. Personally, my lap times went way down when I made a change in the final gearing which required far fewer gear shifts at Road Atlanta. I could spend that tiny amount of time concentrating on my braking and connecting the dots of turn in, apex and track out.

[don911]

pushing 250k on mine with plenty of track miles. The G50 is almost too good as I really want to do shorter gears but it's hard to justify a $10k bill on the perfectly good transmission. At least with a 915 it gives you a reason to rebuild every 50k miles.

[Matt Monson]

Originally Posted by awhnry

Yes, I appreciate the correction. My post makes more sense with your addition.
And yes, there are always exceptions to the general rules but again with modern automobiles, use the brakes not the trans to slow the vehicle on the street. And dont shift into first gear when the car is moving.

I appreciate your understanding and that final bolded parts IS one of the Porsche gearbox golden rules. They love that stupid those silly 3.5-3.8ish 1st gear ratios and for 30+ years can't seem to get a good drop on the 1-2 shift regardless of gearbox variant. And why? Some say they do it for the magazines, but I'm sorry, but if you can't use the darn thing any other time than when you start at the stoplight and try to save you clutch, then you are wasting my time.

I love the turbo G50's that got the 3.154 instead of the 3.500. Though that's still miles ahead of the 3.818 that they adopted for pretty much all the 6spd boxes from 993 onwards. Useless in my mind, and so useless, that a GT3 owner's manual advises you to start the car in 2nd gear on certain occasions. Silly stuff, really.

[Lyle O]

Great point about not downshifting into first on decel. It takes me back to the first vehicle I ever purchased: my old '65 Dodge van, which had a 3-speed manual trans (shifter on the tree!). First gear was NOT synchronized, so you really could only shift into first when standing still. That taught me well about when and when not to downshift, and I practice that to this day.

[porterdog]

Originally Posted by Matt Monson

On the street, downshifting and using the tranny to decel is just to feel cool and because the engine sounds neat. That's ego.

Must respectfully disagree with the bold part. While I can accept that downshifting to decel has no real advantages over the brakes from a mechanical standpoint, I drive this car because it appeals to my senses. I love the sound of a trailing-throttle downshift like 4-3. It's not ego, it's pure unadulterated enjoyment.

I can live with the results; avoiding the behavior would force me to enjoy my car less, and what's the point of that?

(NB: I drive it on dirt roads and in the snow, too )