Feel something strange when shifting

ace123 · 10-28-2008, 09:38 PM

Hi,

I have a 1987 911. Here's the deal. When I shift from first to second it feels like something is rotating and then catches as it engages in 2nd gear. It only happens when going from 1st to 2nd. The feeling is in my hand through the shifter knob.

If I clutch in on 1st and then wait a bit then shift two second, I don't feel any rotational type of thing.

What you think is going on? Is it no big deal or should I be worried?

Thanks!
Marc

rnln · 10-28-2008, 10:23 PM

umm... I don't know if I am correct but I feel it too. There are many thread people talked about it. What you are doing is pausing in neutral, right? It's a known solution for this problem. Double clutch also help. Mine is worse going into third.
Is this your new problem or it's always been light this?

Aurel · Aurel's Garage

It sounds like synchro. What you feel is the gears meshing together, because your synchro is worn and does not slow down the first gear enough. When you put in neutral or give it more time with the clutch, you don`t feel that meshing together because the speed difference is less between gears, causing a smoother engagement of the 2nd gear.

Aurel

masraum · 10-29-2008, 05:35 AM

I agree with Aurel. But I'm not sure it's necessarily a worn syncro. I seem to remember my G50 (both of them) being like that in my '88. G50s are notoriously notchy between 1st and 2nd especially when it's cold out.

KFC911 · 10-29-2008, 05:50 AM

Quote:

Originally Posted by masraum

...G50s are notoriously notchy between 1st and 2nd especially when it's cold out.

Yep! Mine only does it when cold, and the first few times shifting, so I take it nice and easy and double clutch on the 1-2 shift the first few times and it's eliminated. FWIW, mine didn't do it until I changed the tranny fluid the first time several years ago. I don't know what "was" in there, but I filled it with Mobil 1 (but not the "good" stuff, I purchase mine from Autozone or somewhere), and the "notchiness" appeared. I've since tried Amsoil, and now have Redline in her but it's still there. I'm still thinking that the gear lube change made a difference, so I'm thinking of trying Royal Purple (maybe what was in her?) or the "right" Mobil 1. In the meantime, as I've done for several years, just "baby" the first few shifts, and you'll be fine. Make sure you're using synthetic (regardless of brand) for your G50.

ace123 · 10-29-2008, 02:16 PM

Yeah - you are right. When it is cold it is definitely worse. Once is warms up then it feels much better.

2 questions:

1) If I accidentally do the fast shift, then what is happening? Am I effectively grinding the gears down?

2) So if I had to fix that what kind of cost am I looking at and what is involved? Is it a tranny rebuild?

Thanks!
Ace123

burgermeister · burgermeister's Garage

Mine is the opposite - shifts pretty good when cold, and gets crappy as it warms up. The, when it gets really hot (track day), it shifts better again. But always notchy, 1-2 and 2-3. I suspect it's synchros.

I have the Delvac Mobil1 in there BTW. It replaced who-knows-what, possibly the original fill. I have considered trying Swepco - I know it's not the 'proper' oil, but perhaps it will improve the shifting.

I have also noticed that the generally prominent gear rattle (idle in neutral and accelerating in any gear below 2000 rpm) is absent when the car is cold (40 deg or so).

Zeke · 10-29-2008, 05:38 PM

Quote:

Originally Posted by ace123

Yeah - you are right. When it is cold it is definitely worse. Once is warms up then it feels much better.

2 questions:

1) If I accidentally do the fast shift, then what is happening? Am I effectively grinding the gears down?

2) So if I had to fix that what kind of cost am I looking at and what is involved? Is it a tranny rebuild?

Thanks!
Ace123

You are not necessarily grinding gears down, but you are not doing your synchros any favors. The dog teeth are what gets damaged and the result in the end is that the tranny won't stay in gear.

Who knows what a rebuild costs? I've heard all the way up to 10K. That's insane. But, I think every part you buy new for a tranny rebuild costs a hundred bucks each.

Aurel · Aurel's Garage

Quote:

Originally Posted by milt

You are not necessarily grinding gears down, but you are not doing your synchros any favors. The dog teeth are what gets damaged and the result in the end is that the tranny won't stay in gear.

Who knows what a rebuild costs? I've heard all the way up to 10K. That's insane. But, I think every part you buy new for a tranny rebuild costs a hundred bucks each.

Mine was rebuilt for ~$2.5k. But they replaced bearings, gears, synchros...Only synchros might have been enough, and would have cost only ~$1k, but you never know...shifts really well now.

Aurel

ace123 · 10-29-2008, 07:47 PM

Yikes! 2.5K is some major cash. I know its a tough question, but how long do you think the tranny can last in its current state. Especially if I'm really easy on the shifting?

burgermeister · burgermeister's Garage

As long as you can perform your shifts clunk and grind free, you're not damaging anything. You just have to tolerate barely keeping up with the minivan ahead because you take 2 to 3 seconds for a 1-2 upshift.

You might try taking 1st only to 5K instead of 6K ... it seems to help the shifts on my car at any rate.

KFC911 · 02:31 AM

Quote:

Originally Posted by ace123

Yikes! 2.5K is some major cash. I know its a tough question, but how long do you think the tranny can last in its current state. Especially if I'm really easy on the shifting?

Learn to be smooth and easy (especially when cold and if it's "catching" on the 1-2 shift, you're doing damage, and you NEED to change). You can't speed shift these cars even when warm, and 1st is just to get you going. I take my car up to redline on a regular basis, but ONLY after everthing is nice and warm...keep her below 4K until warm. Do that, and your tranny will last a long, long time...abuse it...maybe 1 year

.

ace123 · 10-30-2008, 12:51 PM

Yeah, I read in the manual that you should keep the RPM under 4k for 10 minutes or something like that which is probably until it is warm. I usually shift between 4k and 6k on every gear except for 1s to 2nd. When cold I shift when the RPMs go back to <1k.

JWLindsey · 10-30-2008, 03:51 PM

A little late to the party, but my '87 does the same thing. It did improve a bit with new shifter bushings and a switch to Redline NS fluid but I can still feel the synchros shaking hands on the 1-2 shift. It does improve as the fluid warms up but you can always still feel it and high revs don't help at all. My trans is the original with 176k on it, so this may be just high miles or the way the G50 works.

Good luck.

-JWL

rnln · 08:55 AM

all the above explained the grind and that weird feelling, what about the luck. What causes the clucking feel?

My G50 used to shift normal even witth he mobile1 from autozone. Now I have redline and new clutch (spring disk) and has this problem, also I can produce slight clunk once in a while. I think it happen when my gas/right foot is a little (mm sec) late compare to my left/clutch foot, or depress clutch a little quick while moving. Is this normal or is there something with the installation? Knowing the famous rattle with spring disk clutch at very low rpm.
added: actually I an not sure it should be decribed as clunk or light thump feelling.

Quote:

Originally Posted by burgermeister

As long as you can perform your shifts clunk and grind free, you're not damaging anything. You just have to tolerate barely keeping up with the minivan ahead because you take 2 to 3 seconds for a 1-2 upshift.

You might try taking 1st only to 5K instead of 6K ... it seems to help the shifts on my car at any rate.