Can only shift into reverse, 2nd and 4th gear!

[Wolff1953]

I have a 71 S with a 901 transmission using the dog-leg 1st gear shift pattern. Periodically, over the last couple of months, down shifting from 3rd to 2nd felt very, very strange... lots of pressure on the shift motion. It only happened twice before last week when the shift motion really went south. Now, I 'm able to shift only into reverse, 2nd and 4th gears. 1st, 3rd and 5th are nowhere to be found. Gear oil was changed to Swepco 2 mos ago and all shift rod bushings are less than 6 mos old. Any ideas as to what the problem(s) might be and what it would take to get this P-car back out there?

[MBAtarga]

Sounds like the shift coupler has slipped - that's why you can only hit the "backward" gears.

[Wolff1953]

Hi - I already checked the shift coupler at the rear of the tunnel and it's fine. It's still at the scribe marks that I put on when the shift rod bushings and cup were replaced.

[john walker's workshop]

hold the coupler with one hand and move the shifter with the other. is the shift rod moving precisely with the shifter movement or is there obvious slop? if the shift handle contacts the edge of the shift tower before full engagement hap[pens, then that could be the problem.

[barney911rs]

I agree it definitly sounds like linkage adjustment, even if it has not moved per your marks.

[Wolff1953]

Many thanks to John & John. I'll retest the linkage this weekend. I hope that's it!

[Wolff1953]

I took out the drivers seat, pulled back the tunnel carpet, removed the tunnel cover and tried out John Walker's test method. With the exception of some North to South slop in the coupler at neutral, the gear shift movement matches the coupler. I compared some pixs I took of the coupler 2 years ago with what it looks like now and they are exactly the same. The pix is attached below. Is there an inspection cover I can remove on the trans body to look and see if the gear selector is hitting or binding on something? Any idea what I would be looking at and looking for? Thanks!

[barney911rs]

If you did not change anything, I still think you should loosen up the nut and bolt on the left in your picture and slide it back just a little bit, tighten it back up and see if you can get the other gears.

[Richard Burns]

Try putting your car in neutral and check to see if the gear stick is vertical below the bend. I would anticipate that it is laying back that would be why you cannot select 1,3, & 5. Make the necessary adjustments undo the bolt at the rear coupler and shift the stick forward so that the part below the bend is vertical.

[Green 912]

If you have not done so you might want to check the motor and trans mounts too. A loose bolt can let things shift a little and mess up the shifting.

[mhackney]

It looks like you also have worn bushings. That extra slop can affect shifting.



Cheers,
Michael

[Wolff1953]

Yes, that slop in the bushings equates to about 1/2" in gearshift knob travel. I've read that the center hole of the bushing is supposed to be somewhat oblong and not perfectly round so I wasn't too worried. Also, this picture matches the one of 2 years ago when there wasn't a shift issue, so I don't think it's the main cause. I'll check the vertical orientation of the gear shift in neutral and will also try adjusting the throw of the the selector as suggested. Many thanks!

[john walker's workshop]

stock bushings look like that. get the replacement ones from pelican with the round hole.

[Wolff1953]

Thank you John Walker. I'll R&R the bushings when I get this shifting issue sorted. Can you tell me a bit about checking to see if the gear selector is inop in the trans? If I drain the fluid and open the small cover on the passenger side of the trans, what should I expect to see? Thanks again.

[Wolff1953]

Tom Amon of Mobile Works West came by last Thursday, tried a couple of shifts and thinks that the problem is internal to the transmission. Something is not where it's supposed to be and is blocking the fork selector. 1 1/2 hours later the trannny was in his truck and headed for a teardown. I'll replaced the coupler bushings when I get back ( in Shanghai now) and Tom should have it all ready by then. I'll post what he finds out. Thanks to all for their contributions!

[zazothex]

sorry bout the bump, but I've just had the same thing happen, only I lost the top gears; 2nd and 4th. The others work great, including reverse.

Did a re-adjustment of the coupler do it or was it a tear-down solution?

[Wolff1953]

Replacement of the shift coupler did not fix the problem. The shift fork inside the tranny was found to have some deep scratches on it. Tom felt that something had been stuck up against it and prevented the fork from selecting the gears. That something was never found; may have come out when the gear oil was drained.

[zazothex]

Bummer. I've had that sucker open once this year. Was hoping not to have to do it again. I'll try messing with the coupler and re-torquing the nosecone. But it sounds like I'm-a gonna have to do some pulling.

Thanks for the reply.

[Wolff1953]

I'm not sure which trans you have. I think on the type 915 there is be a cover on the side of the trans that you could remove and check how the gear selector fork is operating. I could be mistaken as it's been awhile...

[zazothex]

Mine's a 901 from a 914. No such luck. It'd be nice, though.