shiraz

x-post from Asia Pacific/ New Zealand thread. I've not started a thread before, but I have searched & read a lot...
shiraz
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Join Date: Mar 2011
Location: Kaikoura, New Zealand
Posts: 159
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Gentlemen & others ( no lesbots for a while Macca ?), I've a "sometimes problem" changing gear into 4 & 6. Occurs mostly after acceleration in 3rd ( after corner/curve) - feels like binding somewhere in linkage or the notorious nlyon cups ( guessing here , no experience). Won't move full distance & if I release clutch it grinds. No problem shifting into 5th. Replaced engine mounts a couple weeks ago (Rennline SS), but problem seems to be becoming more frequent. Seems to happen hap-hazardly & come right some minutes later, I always double de-clutch downshifts so don't believe it to be synchros. I think it is a shift lever travel issue...
1995 with single mass flywheel & clutch replaced 40-50tkm ago & behaving normally - no slipping etc
Cheers - David
shiraz is online now

BobbyT

The shifter linkage is not difficult nor expensive to sort out. The nylon cups and other wear items can be replaced (this probably needs doing anyway, if these parts are original to the car), and then if the problem persists, you have eliminated the shift linkage as a possible cause.

I had this same problem, and in my case, found the cause to be rusty transmission input shaft. The splined area of this shaft must be clean and properly lubrication so the clutch disk can move along it freely and release correctly.

Correction of this problem does require removal of the transmission (or engine/transmission if the car is a C4), so the shaft can be cleaned and lubricated.

If you do a search on this forum for "rusty input shaft" you can find more information.

shiraz

Thanks Bob, I've read numerous threads ( including yours) & 100's of posts, most with the rusty input shaft issue seem to describe problems shifting out of gear rather than into the next gear.
Will take to local indy (200 km/125 m away) when work allows - needs new plugs anyway. I still think - may be wishful thinking - it's a linkage problem.
Car is (RoW) C2, so shouldn't need to drop engine as well to check shaft for rust.
Many thanks, cheers - David

pp000830

FYI on the 993 there is no need to remove the engine to drop the transmission and service the clutch.

Cupcar

It's pretty easy to R&R the shift linkage to service it and check for rust on the shift rod of the gearbox and undo that sliding the shift rod off the transmission shaft.

The shift boot pulls off the lever, just use a soft tool to release the perimeter of the boot where is meets the center console. There are spring clips on the driver side of the console and the perimeter wire of the boot fits into a slot on the passenger side. So gently pry drivers side and it will drop down and passenger side will release. Pull shift boot straight up.

Then remove center tunnel cover under car (a million 10 mm nuts), undo 2 bolts holding the forward end pivot's bracket, release the boot at the transmission to uncover the bolt holding the shift rod to gearbox.

Then note that the main shift tube in the oval nylon bushings is retained by a circlip wire at each end that can be gently pried off - one end of it hooks into a hole in the tube. Remove one of these clips.

Then support the weight of the shifter parts with one hand and pull out that main tube with the other hand and you can drop the whole shift kit out of the bottom of the car to service it. A friend inside the car directing the shift lever helps here, but I have done myself.

There are metal rings built into the nylon oval bushings left behind in the chassis, I have seen these rings fall out and make the shifter sloppy because the bushing is without stiffness then.

Not a bad time for a Rothsport shifter and golden rod, or factory RS shifter and factory RS shift rod. The forward bearing cup can be replaced with a 10 mm rod end easily with a simple bracket fabrication.

BobbyT

The cause of the shifting problem on my car was rust on the transmission input shaft, the splined portion the clutch disk must slide slightly back and forth to engage/disengage.

Cupcar

That would sure cause a problem!! Moving to SoCal would help

vincer77

Does it go into second gear ok? Mine ended up being differential needle bearings falling into cavity behind shift rod.

shiraz

Hi Vince, have not had any issue with 2nd, however the problem has only occurred occasionally when shifting up from 3rd after brisk acceleration out of a curve. In these circumstances I haven't tried going back down to 2nd. When it happens I settled for 5th until it "un-binds" itself.
Have read your posts & those of Gerry Kokoszka - no 2-4-6 gears.
Cheers - David