VROOOMMM...shift...crunch...ugh

UTKarmann_Ghia · 03-17-2003, 08:41 AM

Okay, I've been driving a stick shift for years and I'm good at it. Why the heck does 2nd gear crunch when I'm runnin the car? Usually doesnt crunch up to 4k rpm, but after that it's almost certain to crunch. I've replaced the helper spring (thank God) and successfully adjusted the clutch and linkage. Does everybody's 2nd gear crunch? Ugh...

Rot 911 · 03-17-2003, 08:50 AM

It will unless you in stop neutral for a split second. Just something you have to learn about the 915 transmission. Welcome to the club.

UTKarmann_Ghia · 03-17-2003, 08:54 AM

Does first gear have similar issues? About 1/3 of the time I have to take a couple of shots at getting it into first gear. It doesnt crunch (and now it's much better with the new helper spring) but sometimes you have to force it in. I have no other trouble with the tranny and it feels really good everywhere else.

HarryD · 03-17-2003, 09:03 AM

Welcome to a 915 tranny. When you shift, think..

Out of gear, Porsche, in gear.

old_skul · 03-17-2003, 09:12 AM

First thing to do: replace all the shifting linkage bushings. That means the ball cup bushing under the shift lever, the shift rod bushing at the shifter end, and the coupler bushings at the linkage coupler between the seats. Adjust your coupler while you're at it.

Also, drain your tranny oil, and replace it with Swepco. Make sure to loosen the top (fill) plug first, to make sure you can refill the tranny after draining it. You need one gallon of Swepco 201, the proper hex wrench, and a hand pump to do it. While you're doing that, it's a good time to open up the access plate on the tranny and see if your shift rod guides are in okay shape, and also see if any gear teeth fall out.

Still crunching? Time to replace synchros and dogteeth. A tranny rebuild will be $1300 or more, with proper parts, but a rebuilt tranny with core change can be had for around $1300.

UTKarmann_Ghia · 03-17-2003, 09:18 AM

I've replaced the ballcup and shift rod bushing. The coupler will get new bushings next week (since I cant replace them myself). Also got a new Porsche short-shift kit. I'm doing everything as to not replace/rebuild the tranny. I'm almost done, but if I do pause, it's fine.

Jamie79SC · 03-17-2003, 09:18 AM

Double clutching works wonders on the 915

old_skul · 03-17-2003, 09:21 AM

You can replace the coupler bushings yourself. You just clamp the peice the pin goes through in a vice, and hit it with a hammer a few times. It comes right out. You then R&R the bushings and pound the pin back in.

The Swepco will make a huge difference too. And yes, Jamie's right - double-clutching works wonders.

UTKarmann_Ghia · 03-17-2003, 09:24 AM

sounds cool, I purchased the bushings (sitting in my garage now), but I read, in 101 projects, they had to be "pressed" out and in. Cool, glad to know I can do that myself...I'll do it tonight and let you know

I did remove/inspect the coupler and they are certainly loose (most likely stock).

911SC Pilot · 03-17-2003, 09:55 AM

And double clutching is what???

jhugh · 03-17-2003, 10:03 AM

double-clutching:

1. clutch in
2. shift out of gear, into neutral
3. clutch out
4. blip throttle (if downshifting)
5. clutch in
6. shift into next gear
7. throttle to match new gear
8. clutch out

happens a lot faster & smoother than it sounds, with some steps happening more or less simultaneously. Definitely works wonders w/ a 915.

Dan Owens · 03-17-2003, 10:19 AM

Matt,

I hate to cause a problem here or dispute another P head but I'm going to give you different advise than Mark (Old Skul). DO NOT HIT THAT PIN WITH A HAMMER! Chances of breaking the coupler housing are very good should you do that. I know a lot of people have done it without problem but it doesn't come out with one whack so you'll be beating on it and the coupler is cast. I know several people that have cracked or broken the housing by trying to drive the pin out with a hammer. Use a vise and a couple of sockets and press the pin out. You can also use a large C clamp and a couple sockets or even go by a gas station or parts store that has a press and have then remove it for a couple bucks. It comes out fairly easy with a press of any type and you can swap the bushings in a 2 or 3 minutes easy.

Dan O
84' 3.2 Targa

nostatic · nostatic's Garage

"force" and "915 tranny" don't go together. The 1st to 2nd shift requires patience, timing, and a gentle touch (breathing through your eyelids helps too).

UTKarmann_Ghia · 03-17-2003, 10:27 AM

Dan, always happy to hear differing opinions since it helps me limit surprises

How would I use the sockets to press a pin out? Not quite sure what you mean. Could you please explain what you mean? Thanks.

jhugh · 03-17-2003, 10:30 AM

When Ted Robinson (machinist buddy) and I put new bushings in my shift coupler with a press, the pin wouldn't quite go in all the way... just the last couple millimeters were left. Ted (a man with EONS of experience with metal objects) said he thought if we pressed it any harder we'd crack the coupler. So we left it the way it is and it's just fine, with a much more solid & positive feel now. At 104K miles, the original bushings were well worn.

Cheers,

magilla · 03-17-2003, 11:41 AM

UTK, I am like you. I have been avoiding a rebuild for 2 years now. First and second gear are pretty bad, but I can always get it into gear, as long as I am do it slowly and easily. I anticipate rebuilding it myself when the funds are available, but I will likely be babying it for another year.

As far as I am concerned, it takes some of the fun away from driving the car, but it isn't getting any worse.

Dan Owens · 03-17-2003, 11:44 AM

You need to make some space for the pin to push out through if you don't have the proper press and attachments. So if you use a large socket that matches to the outside coupler diameter ( on the side if you're looking at the end of the pin) and put a small socket extension that matches the pin diameter on the opposite side, the force pushing on the small socket/pin pushes the pin into or through the large socket enough to get the two coupler pieces apart. You reverse the sequence to press the pin back in. This is only if you're doing it yourself and don't have a real press but a vise or large C clamp.

UTKarmann_Ghia · 03-17-2003, 11:47 AM

Ok Dan, I see where you are going, sweet. I was trying to envision just how I would do that in a vice and where the silly pin would go! I'm going to give that a whirl tonight as we're supposedly going to get some snow tomorrow and the next day...perfect time to take her off the road for a day or so

Dan Owens · 03-17-2003, 12:33 PM

Take you're time with the pressing and don't over torque it quickly. It may seem like it's not going to move at first but should once enough pressure is applied. I did mine with just a large C clamp and it worked fine. Took all of 15 minutes and I was ready to put it back in the car. Mark your position on the shift rod shaft (both directions) before you take the coupler loose. You should then be able to put it back and be pretty darn close to aligned.

old_skul · 03-17-2003, 12:33 PM

Dan's right, of course. The press method is far kinder to the coupler. Since I'm actually just a neanderthal when it comes to this stuff, though, the hammer method works great. Mind you, I wasn't wailing on the pin - I just tapped on it with a peice of wood on the end of the pin to avoid dinging it up.

The vise method with a couple of sockets is the best, though.