Transmission issue
 

Just overhauled my 1976, 911S engine and 915/44 tranny. Already installed in the car and sitting on jacks. The engine started great and the 5-speed tranny seems shift good through all the gears and when it is in neutral and the engine is idling the wheels still turn. I checked the neutral position again an it feels in right position and with the clutch depressed the wheels still turn; Has anybody experience this problem before? All the syncros, dog teeth and bearings were replaced. Could it be the clutch grabbing or needing adjustment? Any tips and suggestions will be appreciated. By the way, this my first project car so I have a lot to learn!!

If you step on the brakes or pull the parking brake to stop the wheels from turning, will the engine stall?

+1

You didn't say if you had the clutch in. There is enough friction in the trans to transmit some torque to the wheels while in neutral, if they are off the ground they could spin. That is why you should push in the clutch when starting your car.

I had the clutch in and did not step on the brakes to see if it would stop, but I did try the emergency brakae on and it start to smoke the clutch, so I stopped. This all happened while I had the shifter in neutral.

Did you recently install a new clutch? If so as weird as this might sound, you may have installed the friction plate in backwards. This would not allow the clutch to fully disengage. You may have a fork out of alignment, or has slipped, in the gearbox which is keeping a gear engaged as well.

I would check these things first.

What happens if you push the clutch (while the shifter is in neutral and engine at idle) and either step on the brakes or pull the E-brake? Will the engine stall?

With a good clutch it should not smoke the clutch but rather stall the engine.

I assume you shifted the trans in to all the gears while it was still on the stand?

Autoban, Trackrash, and Hawk thanks for the suggestions and questions. You prompted me to go back and started up my engine again, with the stick in neutral and the car wheels on the floor. With the clutch in the shifter shifts good into all gears; but when I put it neutral, step on the brake, and let the clutch back out, it will stall my engine. With the engine running, if I try to move the car normally in any gear it will not move at all , causing the engine to stall. Seems like it is stuck between gears, is that possible. Any ideas what might be causing this? HELP!!

Its more likely that you have two gears engaged because of missing interlock detent.

OK, so this will tell us that the clutch is working OK since you can "separate" the drivetrain from the engine by pushing the clutch, but when letting the clutch out in any gear or even in neutral the engine stalls.
I would first disconnect the shifter linkage in the tunnel in front of the back seat. Disconnect it by opening the clamp, but leave the coupler on the transmission shaft. After doing this, grab the coupler and see if you can find neutral by moving the coupler. You don't need to start the engine, just roll the car back and forth.

This. If you try to let out the clutch with the car in "neutral" does it appear to be in reverse? You may be experiencing the classic "stuck-in-reverse" problem. Here's my previous thread on the issue.

http://forums.pelicanparts.com/porsche-911-technical-forum/659567-915-prob-fixed-big-thanks-pelican-forums-john-walker.html

OK guys, I hope it is somethng like proper adjustment of the coupler! I will take everybodys' "things to look for list" and see if it clears my problem. I feel relieved to know that there is such great experience and knowledge on this subject. I am new to the Tech Forum and I am glad I joined it. I will keep you gents updated on my trans issue and thanks for the help.

Update! I disconnected the coupler leaving it on the transmission and tried to get it in neutral while trying to move the wheel back and forth---No luck. I also disconnected and removed the reverse switch and chected the push rod but it seemed to be all the way in already. I put the reverse switch back on. Short of taking the trans out and going trough it again is there anything else I can chedk or try that anybody can think of? Hope everybodys' day is going better than mine right now! :o)

I stick with my first comment, stuck in 2 gears at once. Unfortunately the box has to come out. The good thing is that you don't have to buy anything, or just a detent and spring.

BTW always go thru the gears and spin the input shaft when assembly of a box.

Thanks ganun, I figured I would have to take the trans out again, just hope it is something simple as a detent spring missing or broke.