901 shifter questions...

dotorg · 09-02-2003, 09:51 AM

Still chasing down the source of my disappearing gears and sloppy shifting...

Does anyone know of any good writeups like this for the 901? Or that'll explain whats different between adjusting the 901 vs 915?

My rear bushings seem to be okay in the metal widget under that rear plate between the back seats... so the next things I guess are checking the adjustment and the shifter itself (which the previous owner said was recently rebuilt...)

Hopefully its not the tranny itself

jpnovak · 09-02-2003, 09:59 AM

You should be able to follow all the suggestions for the 915 to get the 901 to shift better. Check the following:

ball and cup bushing on the base of the shift lever

Shift rod bushing mounted to bracked on base of shifter.

Shift coupler bushings (you already did this). Are you sure they are not worn? There should be very minimal fore/aft slop, none in other directions.

Next is the tranny itself. You should be able to select all the gears by hand. Its helpful to disconnect the shift rod from the coupler for these tests. If you can select all gears then align for proper shifting. Make sure shift shaft is in center plane (neutral) and rotate shift shaft in full clockwise direction. simultaneously, push shifter over to the 4th/5th plane. The base of the shift lever should be perpendicular to the floor and tighten the shift rod. You should be aligned now. It may help to have an extra set of hands from another person to help with the alignment. It only works well if the shift shaft on the tranny is fully rotated.

If you can not select gears by hand then there may be internal issues with the tranny. best of luck.

Jamie

dotorg · 09-02-2003, 10:06 AM

I can select gears most of the time, its just that first disappears from time to time. Normally I can sort of feel it "hook" first, and I can tell it engaged.

What happens is sometimes after a while driving the car, first no longer is "there". You can feel around for it with the shifter, but it never gets that "hooked" feeling. Usually I have to just keep trying to engage it and it'll eventually go in.

I'm hoping its not dead synchros... the mechanic who did the PPI said the transmission was fine, but I have found a lot of things he said weren't problems that were, so I'm not entirely sure its not the unit itself.

Jim Garfield · 09-02-2003, 10:13 AM

I don't know if this will help, but I just had a similar problem with a 915. Check this thread Which came first, no 5th gear or spinning shift lever?

jluetjen · jluetjen's Garage

I've got the factory shop manuals with all the stuff on 901's. You're welcome to take a look and check the adjustment when you stop by. I'm guessing either some bushings are bad or maybe the motor mounts(???). I'm not aware of syncro's making a gear "disappear".

dotorg · 09-02-2003, 10:20 AM

Heh, thanks John. Hopefully Saturday will work for me swinging by. Thankfully this isn't a huge issue, because in an hour of driving it, I may only have it happen twice that I can't find first on the first or second try. It just sucks when it happens on Rt 3 or something, and people start honking!

jpnovak · 09-02-2003, 12:40 PM

If you are having problems getting into first I can think to two things. First is that the linkage/coupler bushings are worn out (replace ALL of them) and second is that possibly first gear is worn not allowing it to mesh. This wear is due to work syncros and grinding gears/dogteeth. Motor mounts could be a possibility.

My 901 will not go into first when rolling above 5mph. It has worn syncros. Double clutched or not, it won't happen. How easily will it drop into 1st right before you stop? That last 2 ft before you are at a dead stop. It should go into gear very easily at that point.

Jamie

dotorg · 09-02-2003, 12:51 PM

Usually if I simply can't find first its when I've been stopped with the car in neutral. It'll give me a snick in the best of times if I go straight to first... I pop it into second and then into first, and there's no problem. The mechanic said that was normal, something with the large physical size of the 1st gear.

Vintage911Racer · 09-02-2003, 01:37 PM

Have you tried replacing the bushing up front? Not the press on fitting on the bottom of the shifter but the one that is attached to the tunnel where the shift rod goes through. It is located right at the shifter itself. This can get worn, sloppy and cause eratic shifting. It is a circular plastic bushing that the shift rod actually runs through before it get to the shifter itself. Give that a try.

dotorg · 09-02-2003, 01:49 PM

I haven't pulled that part out yet to check.

Jim Garfield · 09-02-2003, 01:56 PM

I agree with the above advice, the shift lever coupling bushing and the shift rod bushing can be replaced in about an hour and cost $20. for both.

Evans, Marv · 09-02-2003, 02:03 PM

I had a very similar problem with my '72 when I first got it. I'd try shifting & there wouldn't be a gear to go into. In my case, it was worn bushings at the shift coupling. I replaced those and the bushings at the shifter, since I didn't know how old they were. It shifted fine after that.