Dbltime

Here is the test: stock '97 993, RS LW flywheel and clutch. Runs and shifts perfectly. The trans/motor is removed and the gears are changed to RS spec, steel synchros, RSR t/o bearing.

First track outing after 4 laps the car will not go into 4th on the downshift or 5th on the upshift. Not everytime but often. Does not grind but you meet resistance and can't find the gear. Clutch? Slave? The first few laps the car seemed to shift fine. Also it pops out of 2nd when you lift off the throttle but that may be unrelated.

Any thoughts?

chris walrod

if those are the only gears you are having problems with, might be a shift fork alignment issue?

Were those syncros replaced?

chris walrod

Sorry about the synchro question, I just reread the question...

Chris Cervelli

My bet is that the detents are not functioning properly. This is kind of a difficult thing to explain.

There are 4 spring loaded plungers in the detent plate. They provide detent for each shift rod, Reverse, 1st and 2nd, 3rd and 4th, and 5th and 6th.

These provide some of the 'click' you feel as you go into or out of a gear.

Also contained in the detent plate are 2 pins, two 'footballs' and a long pin with football ends. All these bits are supposed to make it impossible to engage more than one gear at a time.

I think something in the detent plate is not right. When you can't get 4th or 5th it is because the detent plate 'thinks' that the trans is already in a gear. When you pop out of 2nd I'll bet it is because something won't let you get all the way into 2nd.

The other thing that goes wrong is the sychro ring's shoulder gets jammed into the slider hub so hard it sticks there. Then the trans kind of acts like it is in two gears at once. Usually this only happens when a gorilla is driving the car, but I saw a nice lady do it once.

These gearboxes are not all that fussy. If you don't do anything wrong during assembly they should work great. Were all the other RS shifting parts installed at the same time?

Chris Cervelli
Technodyne Inc.

Dbltime

Thanks for the input Chris/Chris. Yes all the RS parts were installed.

The shop that did the work is going to tear it down and stand behind it.

Why would it shift for 2 laps then start acting up? This was Sebring so they were long laps with only 1 2nd gear turn. Would heat effect this?

kary993

Bill,

Have you (or your mechanic) gotton to the bottom of the issue? I would like to know what happened if you don't mind posting.

Thanks!

Dbltime

I delivered the car to their shop this afternoon. They will open it up and see what the deal is. I hope to make the CMP club race next weekend. These cars are so dependable even in a race form that this gear box issue bummed me out.

I am not convinced the taller gears are a benefit on a long track. Short track no question.