928ntslow

Since I haven't driven anyone elses 5 spd, I would like to know if my GTS' gearbox is the same as the rest. I know gear boxes vary from one car to another and from manufacturer to manufacturer.

Seems like the 928 is no slush box. I am still getting to know the car, but find I have to string it up a while in 1st to get a nice positive shift into 2nd, without the car jerking back when letting out the clutch. The only way to avoid that is to stomp the gas. I guess it is necessary to bring 1st up to at least 3500rpms for a clean shift into 2nd.

The real question is though, my gear box is not a quick shifter. I find that the quicker I shift, the harder it is to get the shifter through the gate. I can also feel the tail end of the gears spinning before they mesh...this is while the clutch is in and I am shifting from 1st to 2nd, 2nd to 3rd or 3rd to 4th. I could probably make the instance happen in all gears if I jam the shifter to each gear. There is no serious gear grinding going on, but just the shifter not slipping right into gear and the gears not instantly meshing.
I HAVE found that if I shift slowly and smoothly, this occurance does not happen. I just have to be a robot and be very methodical about the speed of the shifts. Double clutching will help too, but who has time for that!

After I got the car, I changed ALL of the fluids and bled the brake system and the clutch slave...used the Super Blue. I thought I had a bit of air in the slave and re-bled it this past weekend, but still the same shift persnicketyness.

Is there a trick I need to learn or is it possible that 2 or 3 of the synchro's are going out?

BTW, no noises when sitting in nuetral with clutch in or out...or even in gear with clutch in.

ErnestSw

My experience with the GT is similar to yours. The 928 manual gear box (this is my third manual shift 928) needs a firm push rather than a quick snap. Once you're used to it it seems quite natural.
I've never driven an automatic 928, but if they're like most automatics they're designed for smoothness when driving conservatively. The manual shift will always need more revs for smoother shifting around town. I usually shift up around 4000 rpm which leaves me in the torque band after the shift.
It's unlikely that your synchros are the problem unless you're grinding.

Blown Beast

What fluid did you put into the box/rear end?
Did you remove the slave cylinder from the bell housing and push the rod in by hand all the way to the end a couple of times?

Gretch

I can easily shift my GT up or down through the gears without using the clutch at all....done the usual way, matching engine speed to gear speed.

The only time I have found symptoms like you mention is when the weather is cold and the car has not warmed up yet....I chalk it up to lack of sycronization (thick gear oil?). once the car is warmed up a bit she shifts just fine, otherwise I need to run her up a bit in first, or she will grind her teeth going into second.

Generally I don't drive my 928 after Thanksgiving, so it doesn't occur very often...

Weissach

If you have to wait until 3500rpm to get a clean shift, there is something very wrong. I usually upshift at about 1600rpm(because there is so much torque, theres no need fo more rpms).The 5-speed should be very smooth. I find 5-speeds smoother driving the the automatics. How many miles are on the car?? Maybe the flywheel is warped or bad syncros. Have it checked out.

Jim R.

On my GT, smooth gear changes are not a problem at any RPM's. The gearbox does not like to be forced into the next gear, but can still be shifted quickly. I have gotten more accustomed to it after putting some more miles on, but it is not as easy to shift quickly/recklessly as a couple of prior cars, my '98 M3, or even '00 Boxster. I did change to Mobil 1 synthetic in the tranny and rear, with smoother cold shifts than whatever was in there when I bought it.

If the car "lurches" with low rpm and light throttle shifts, there may be something wrong with the car. Is there anyone local with another 5spd to try driving? (or have someone drive your car) See if there is a big difference with yours.

Jim R.

928ntslow

Rob, I had the slave off and pushed the rod in once. I made sure it was seated well. Wouldn't bleeding, allow the plunger to recess all the way back into the cylinder anyways? I re-filled with Mobil 75W-90 Synthetic. I initially thought that the clutch was not disengaging all the way to where I would have to adjust at the pedal, but due to no noise at any time as mentioned previously, I disregarded that.

Weissach, I don't have to shift in the higher rpm range out of 1st, but if I am not on the throttle by the time I ease the clutch out, the car will "grab" causing a jerk when the clutch engages. Basically feels like poor shifting by the driver....though I know what I am doing...I think, LOL.

Low rpms and easy shifting can be achieved, but it is certainly not smooth like an auto tranny. I have tried different rpm ranges and it appears that the car likes to be driven with some aggression.

I have heard of others having the same issue as to where they have to shift a bit slower and more precise like the Ferrari gear boxes. I just thought the P car boxes allowed for quick performance shifting.

Scott M.

Keith;

As Rob mentioned, do a back bleed on the slave, do it about 5-6 times with the resevior cap removed. Nice and slowly.

The other considerations are a worn guide tube in the clutch or a worn out ball cup/clutch fork bushing.

Do you have any play vertically up/down in the shifter?

Scott

SharkSkin

Keith, you'll get used to it. I know I have a different box, but these are big, chunky units, and you have to be a bit patient with the syncros. I'd say just focus on being smooth and the speed will come with practice. Now that I'm used to it, My OB shifts like butter, though downshifting into 2nd takes some care, downshifting into 1st over 10mph or so is risky, and then there is the very rare grunch into reverse.

Just stop trying to shift it like those other cars you mentioned.

928ntslow

Interesting suggestions Scott. When you say back bleed, do you mean remove the slave and remove the resevoir cap, then push the rod slowly into the plunger 5 or 6 times to remove any air pockets?

Granted, the car is a 93 and only 78K on the clutch, but the PO could have mushed up the clutch. I would expect that with the issues you had mentioned, there would be some obvious noises coming from the clutch housing.

Dave, no issues getting into R or 1st.

drnick

definitely try running a quality synthetic oil in the box. mine sounds similar to yours but is better the warmer it gets and the higher the rpm when changing.

ColinB

Keith
My 89GT has the same slow shift with a ****** from 1st-2nd if you don't get it just right. I think it's inherent. However, before you concern yourself with anything mechanical check and change if necessary the transmission oil. Believe me you NEED Mobil 1 or suitable synthetic equivalent. It made a huge difference to my shifting .

Jim M.

Keith,
I had the exact same problem with my 89 GT, after changing the fluid to the Mobil 1. It wanted to grind all the time and I could feel the tail end of the gears just like you discribe. It was not that way before the Mobil 1 so I changed to Swepco and never had the problem again. I think the Mobil 1 gear oil is just to slick for our syncronizers. Try an oil change again and I think you'll be pleased.

Jim Mayzurk

Scott M.

Keith;

Yep, pull slave, pump your rod 5-6 times..

I loosen the bleeder valve and attach a plastic hose (brake bleeder) to it. Slowly push, pull rod back out as there will be no pressure forcing against it.

My GTS was like what you described, but I adjusted the clutch, bleed the line and taaa-daaah. Like butta (I have a twin disc setup though).

Speaking with Jay Kempf years ago about difficulty shifting he was certain that a worn intermediate shaft will also be a cause. Personally, I can't say i've seen a worn shaft.

Also fwiw, my 89 GT has some hesitation from 1st to 2nd but that's a slight synchro issue otherwise it is smooth as a Honda.

Scott
928x10

heinrich

Ditto what Nick, Colin, JimM said. Mobil One or other good synthetic. When I got my S4 I had slow or almost gated shifts and thought for sure I would need to replace synchros soon. I drained the ugly blue swepco out that the PO had put into there, and replaced with Mobil One synthetic and that was now going on 5 years ago, still shifts smoothly as butter. My 1-2 shift is just a tad slower than I would like, as in 1/2-second unless I force it (and I don't) but otherwise she shifts perfectly, no grinding and no backlash as you describe.

My 911 does have the symptoms you describe, EXACTLY ... and I haven't dreplaced the dino oil yet .... we shall see.