Transmission troubles

[Porscheguy]

Hello,

I need help !

I recently installed a replacement transmission on my 1966 Porsche 911, which is giving me a bit of a headache, and before I got back to the seller and complain I need to pick your brains,

I guy who sold it to me guaranteed me that the transmission was recently rebuilt and it was in perfect working order, I have no reason to doubt him since He has a reputable Porsche repair business,

having said that, I am having trouble engaging 3rd and 4th gears, all the other gears engaged nicely with no grinding noise.

First, it started with not being able to find 4th gear, I simple could not find spot on the H pattern to engage it, (sometimes 3rd would engage when doing this), this why i suspected the linkage and reset it to make sure it was on neutral when tightening the linkage adapter, now 3rd goes in but it gets kicked back to neutral when I drive the car, 4th is nowhere to be found.

anyone has had this problem and know the fix? or Have I been scammed?

thanks

JCB

[rstoll]

Try the shift coupling adjustment again. Have someone hold the shift lever vertical and against the left stop. How are coupler bushings? Probably just an adjustment.

[Porscheguy]

Robert

thanks for you reply, I fitted new bushings as part of the trouble shooting,
do you think it has to do with the setting and not something mechanical. ?

cheers
JCB

[rstoll]

Hopefully so. It is the easiest place to start. I think it is critical to have the shift lever straight up and to the left for the adjustment. Check out the procedure at Pelicans "911 tech articles". Good luck.

[Porscheguy]

thanks for the info, let me do it using the article and see if it makes a difference,

sunny today in Montreal, perfect day to do it, ( well i would rather be driving the beast )

like Arnold once said, A'll bee bakkk !

[Porscheguy]

To correct myself from the original posting, it is 2nd and 4th gears that won't engage,

I just finished re adjusting the shifter as per the manual and the tech article still no improvement.


I went a step further this time, I disconnected the link coupler and shifted the gears by hand (by twisting and pushing the coupler into gear) and it looks like this :

2nd will engage but it needs a tremendous amount of force to make it engage, otherwise it kicks out, does that mean the synchro rings are still new (like i was told by the seller) therefore, hard to engage? or they are worn out?

4th will not stay put, i don't get that "cluck" sound you get when the gear falls into place, it keeps kicking out.

any thoughts?

if we are talking about a rebuilt, how much are talking to do a decent job? ballpark figure?

Regards,
JCB

[rstoll]

There was a post a good while back about the shifting forks coming loose inside the tranny. Warren can probably tell you more about this one. It involves taking the inspection cover off and tightening the loose component.

[Jim Sims]

There are rebuilds and there are rebuilds; perhaps not all of the worn parts were replaced. Your 2nd gear issue could just be breaking in issues but the 4th gear appears to be a worn sliding (operating sleeve) and perhaps worn synchro rings too. Did the tranmsission shift properly right after it was first installed after the rebuild and then develop problems or was it bad from the beginning? About $1800 for a mechanic to do a thorough proper rebuild. Jim

[john70t]

Two gears on the same side which both don't want to fully engage does sound like the coupler engagement. When I replaced the bushings in mine I lost 5th gear and got worried as well. There turned out to be barely enough room for tavel and engagement at the same time.

Before it's commdemed, try loosing the screw and move the shift lever back just a tad at a time to give it a little more "push" towards those gears. Marking it with white-out gives a better reference.
You can also hold the coupler and try to move the shifter to check the ball and cup up front.

[Targa77]

Mr car wouldn't shift from 5th to 4th without grinding so I adjusted it and now it shifts as good as new. I'm just glad that's what it was instead of having to rebuild my transmission. Hopefully, this is true for your case.

[john walker's workshop]

i would just let the guy that provided the trans have a look. it doesn't take much time to check the linkage and adjust the coupler. i would do it for free if i supplied the trans. the loose shift guide thing relates to the 915 trans. the 901 has a solid guide.

[Porscheguy]

Thank you for all your replies, it is encouraging for some one like me to see that I can count on people with a lot more expertise such what I see here,

I truly thought, it was a coupler adjusting problem what I had here, but after having disconnected the coupler and tried to engage the gears directly at the transmission push rod with the same results I have to discard that theory,
it looks like (in my opinion) something wrong inside,

here are some observation and theories:

loose/worn fork:
1-this will explain why I can easily engage 3 and 5 gears. but not 2 and 4 gears.

2- the 2 gears are not in the same actuating axis, 2 worn forks? could this be possible?
if it were, let's say 4 and 5 gear, that would be easier to diagnose since it would definitely point at a worn fork,

I would love to have the guy who sold it to me have a look at it, however, he is 1500 miles away, (let this me a caution for anyone buying something long distance).

At this point, I don't want to open the gearbox because of the liability issues that could be void by me doing so. I will wait until I work something out with the seller before exploring this venue.

before I make the dreaded decision to take the tranny out, does anyone else have any other suggestions that I could try while the tranny is still in the car?

also I am in the market for a good 5 speed 901 transmission. ! ( I will need guarantee that it is in good working order though)

thanks
JCB