Guys with 915 Transmissions, help! Options

[RiqueMar]

Jumping right in to the 3.6 project, there has always been an issue shifting into 2 or 3rd gear. Sometimes it is very easy, and other times very difficult, but inconsistent nontheless; I suspect a bushing issue.

The other day, the problem just got worse. Now, I cannot engage Reverse gear (down and to the right) and when I do, it the car goes forward as if it was in say, 4th or 5th.

I have absolutely no idea what I'm doing when it comes to this setup, as I didn't build it. I know that it is a 914 with a Wevo kit, and what looks like a stock 911 shift mechanism.

[John]

You should start checking bushings. All the plastic bushings.

[zig-n-zag]

I would change all the bushings and then see if the symptoms persist.

A loose cone set screw can exhibit the same symptoms you describe.

Internally, I'd jig the shift forks and check clearances, and check
the roll pin holding the main shift rod dongle hasn't been damaged.

[sean_v8_914]

the black car...Anton?
check the helo flex joints. maybe one is coming loose at teh set screw

[sean_v8_914]

there was some fine tuning on teat linkage that we never got around to finishing

[brp986s]

Welcome to the world of customization. It's no longer a matter of putting things back together the way they were, but determining instead what might have been. You're lying on your back under the car and need to keep in mind that any action taken from the drivers perspective is reversed by the time it reaches the gearbox.

The wide travel across the the 1-2, 3-4, 5-R observed from the drivers perspective amounts to only several mm as measured on the circumference of the shift rod entering the gearbox. Unlike the 914 which has fine splines on the shift rod to make adjustments, the 915 has one place to put the cone screw. That's great if it's right and sucks if it isn't. I thought that I might save time, if not $, by buying the PMS shift linkage. Instead, it ended up costing more and taking more time to make it right. If you search here you'll find my thread on this.

Anyways, I shifted the box into 1st and marked on masking tape on the trans input shaft and on the box to see where 1st was. Then connect the linkage to see if you are getting there. Repeat for reverse. I had to slice and reweld my linkage 2 or 3 times to get it right. Your linkage needs to overcome the slop in the box. There is a limited amount of compensation available. I put a lotta $ in my box to make it tight and it works well. Hopefully yours is ok. Good luck.

[Dr Evil]

You describe external issues. Internals fail in one mode, typically, so if it is sometimes in one way and then the other you need to replace/trace down the externals.

[PRS914-6]

If you have a WEVO there should only be 2 bushings assuming it was installed with u-joints. The cup at the shifter and another at the firewall. The firewall "should" be the self aligning bearing style and not likely to wear out. If plastic, grab the shaft at the firewall and see if it has excessive play at the bushing.

Pull out the 911 shifter and check the cup. Make sure the shifter shaft coming out of the boot at neutral is aiming straight up and down, if not reclamp the shaft until it does.

Mine shifts like my Subaru.....

Also, make sure the shift shaft is not hitting something in the tunnel. Mine did and required some creative bending.

[RiqueMar]

Awesome guys! Thank you for all the responses. I plan to get the car on the lift for a period tomorrow and check it out, it's going to be one hell of a learning experience, and I'll be sure to document with plenty of pictures.

I'm almost certain I'll have more questions, as I'm thinking of popping on the Rennshifter I have.

[ellisor3]

I would change both bushings and the cone screw anyway. The bushings at the firewall and the cup at the shifter. In my case, neither felt really loose, but the combination of wear at both ends caused the problem.

[PRS914-6]

He needs to take some pics and post. Mine doesn't have any cones screws. Without seeing it, it's hard to "internet repair". Everyone does these conversions a little different..... (IMG:style_emoticons/default/smile.gif)