9i15 Trans issue - need input
 

78 911 SC Targa - Few weeks ago, while driving the P-car, came to a red light. Went to shift into 1st gear and the gears started grinding. Turned the engine off - shifted to1st, clutch in, started the engine, when the light changed green, let out the clutch and everything seemed ok. Shifted through the gears without any problem.

Now for the strange part. When I stopped at the next light, was able to shift into 1st without any problem.

Eveything seemed ok after that - checked the oil in tranny - oil level ok. So, last week, backed the car out of the garage, shifted into 1st went around the block to see if there would be any more prblems - again, when I tried to shift to 1st after the car was stopped, the gears would grind again.

So guys, what do you think? Clutch & pressure plate, or transmission. I did replace the clutch 70,000 miles ago - your help is needed.

Thanks

Steve

"A porsche does more then just go fast in a straight line"

first make sure your cable and fork lever are properly adjusted...if the cable is original it could be stretched....also ive seen clutches fail alot sooner then 70k. is there any oil leakage from the rear seal?

check all the linkage parts too.
bushings
connectors
set screw

drain the fluid and inspect. you havent changed the fluid in 70k?

All
 

I replaced the trans fluid about two months ago when this first started happening.

I haven't checked the clutch cable - which is what I wll do today - if that checks out, I guess my next option is to pull the engine and do a visual on everything - tranny and clutch assembly.

Thanks for the input.

Steve

"A Porsche does more then just go fast in a straight line"

This may very well just be an issue of a worn parts in the shift mechanism or a need for adjusting.
Before you take out the engine, check/replace all bushings in the shift train and adjust the play in the tower.
Adjust the clutch as prescribed (The 1mm-play-procedure)
Check the 25mm travel.
Lube the cross shaft and related parts.
If you don't have enough travel, the pressure plate doesn't move enough meaning: the input shaft still rotates when you try to shift into 1st.
A lot of old 915's have some issues with first, the car has to come to a full stop otherwise it grinds.

+1 on the coupler adjustment. It just about sounds like it is either gotten out of adjustment, maybe the set-screw backed out, or the bushings crapped out. But, after checking all items that have adjustment specs, and you check and adjust to spec, if it still is having problems, it may go deeper into the internals of the 915. Good luck!! Tony.

he said he had a problem while stopped....this wouldnt be from the shifter adjustment...that would casue a problem while moving....its either the clutch assembly or cable...the tranny is slightly spinning while stopped. although you should check all bushings in the shifter assembly as they are old if original and probably wearing out. the shifter being out of adjustment makes it hard to find the gears. 9 times out of 10 1st gear downshift grinding is caused by the first gear syncro....its the most used gear and wears out faster then the others

happened to me

set screw loose and 1st grinding


all above threads info a given for starting the fix

To All
 

Appreicate the input - haven't had a chance to check thing out yet but hopefully within the next few days I will.

The clutch was replaced along with the shifting coupler - I did check that out. The clutch cable has total 150,000 miles on it so it is a good possibility that could be the problem - If I am lucky.

One thing that is strange is when this first started happening, I jacked the rear of the car up and removed the driverside wheel. Started the engiine, depressed the clutch and shifted to 1st gear. It seemed ok but with the engine still running, I shifted back to neuteral but the rear wheels still continued to turn.

Could this be a problem internal to the tranny?

Steve

Almost all cars I've ever tried that on have done that, just from drag in the transmission.

It might mean something if the wheel wouldn't stop rotating from light finger pressure on the tire (and at least half the cars I did that on would start rotating again when you released the tire, too), otherwise my vote, FWIW, is "that doesn't mean anything".

Possible dumb question on 86 Carrera, just had the tranny out and apart (roller bearing came apart and 5th gear spacer "missing" and everything is now good) and replaced the clutch (Sachs Power) and flywheel (new stock) but I still have trouble getting into first at slow speeds or at a stop without going into second and then into first. Also, 2nd is very notchy and needs some effort to engage but no noise. Is this typical of a 915 or is it an adjustment issue?

Good shifter bushings and proper adjustment are very important for the 915. Adjustment is easy, and shifter bushing are a 2 - 3 hour job.

Did you replace 1st & 2nd gear synchros and the 1/2 slider? If not, what was the measured installed diameter of the 1st gear synchro?