GregBBRD

It's also entirely possible that someone stiffened up the inner spring tension to get a better definition of the first and reverse gate due to the lack of feel from the short shifter.

Again, the adjustment of the spring tension on the side of the transmission is also an eccentric to adjust the amount of "play" between the main internal shift selector and 4th/5th shift rod.

Proceed with caution, if adjusting this spring!

mark kibort

wouldn't the shorter shifter reduce the leverage and make things stiffer?

maybe its related to the same kind of problem I had, where a shifter fork has moved and the alignment to get the shift rod engaged is not clearing the edges of the cut out.

jeremymilo

Mark, what you experienced is what I've started to suspect. What was your solution? Can the alignment of compoments to properly engage the 1st/Reverse rod be adjusted without taking out the whole transaxle?

mark kibort

I wish I could feel what going on. can you video it and post it to youtube?
if that is the problem, where a shift fork has migrated, the only way to adjust it is to pull the top cover of the transmission .... I can do that easily, in 2-3 mins, as I have a hatch in the race car..... a street car, you would have to do a lot of cutting to do it. probably easier to drop the transaxle.

are you having to wiggle it around to get it to fit into the 1-R slider rail?
or is it just a lot of force? maybe it is that adjustable spring. ill go out to my spare transmission and see what might do what you are talking about.

GregBBRD

Brass shifting forks moving on those knurled shafts is virtually a non-event, when properly done. You'd have to drive like Mongo to get one to slip, unless it wasn't properly torqued when it got rebuilt. Zero chance of the improper torque from the factory.....each one is torqued, double checked, and then painted to show it got torqued.

I've never had one move, personally, or seen one move.

That being said, anything is possible, especially with the amount of rookies that attempt to be a "transmission rebuilder" and rookie drivers trying to break off the gearshift lever.

mark kibort

mine was moved..... or adjusted wrong at the factory. I tend to agree with you ... seems impossible for it to move. but, mine, with factory green paint on the bolts, was 5mm off where it should be...... by the way, racing the 928 last event was a dream with it adjusted properly. no lock out, no pop out and shifting was so much smoother. made for a great weekend! (what a pain having to hold it in 2nd around turns!!!)

anyway, below a pic of mine before adjustment. 5mm off, and marked with magic marker before I moved it.
next a pic of my old transmission where you can see the cut outs to go through the 2-3rd gear slider to the 1-R slider. if the shift forks have been moved or misadjusted, it would make it hard to get into 1-R shift fork.

jeremymilo

Mark, here's a video of what I'm seeing. As you can see, no wiggling required, just force. If it was the shift finger not passing cleanly through the 2/3 rod notch, I'd expect it to require similar force on the way back out of 1/R too, but that's not happening. The opposite actually, it actually feels "ejected" out of 1/R once I disengage from 1st or Reverse gear. Like either a spring is the culprit or the shift finger engagement with the 1/R rod/fork has so much friction/tension that it also "pops" out with some force once I begin helping it out.

BTW, I'm in the Bay Area too, so if you're serious about feeling what's going on for yourself, maybe we can connect.

GregBBRD

You've got all the information you need to diagnosis your problem....any more would be redundant.

Start by fixing those terrible bushings. The front ball cup only can move so far, side to side, before the steel edge hits the ball. When the rear bushings are that worn, the ball cup is in a bind, increasing the resistance. Your are essentially trying to lever off the front ball, with the ball cup, every time you do this. At the very minimum, you are crushing the plastic inside the front ball cup, from the leverage after the steel part of the cup contacts the steel ball.

Report back after that, if your problem continues.

mark kibort

great video... the looseness of the gear shift in gear worries me. doesn't seem like ball cup issues. that effects front to back gear shifting. that seems solid... can you check the gear shifter lever attachment points. You might have had a broken piece right below the shift boot. when in gear, there should not be that much rotational play in the shift rod. its like its not connected back at the rear shift coupler. you can hear that reverse lock out spring clanging away back in the transmission. someone tightened that thing way down?? was it always like that?

what greg is pointing to, is that if that front coupler is not neutral in the neutral position, then going full left 1-R, will allow the cup to hit the ball base and twist the entire shift rod to get it in gear.... acting like a long driveshaft spring. I don't thin that is the issue, but it could be. you can test that by reaching up on top of the torque tube and see if the ball cup is centered. if not, something's going on between the rear coupler and shift ****. that's a lot of play. should be easy to find. if its in the transmission (unlikely) its a big problem. you can see my second picture. its in 4th gear. and it cant rotate side to side or the other shift slider finger hits the 2-3rd slider bar. it only moves a 1/4" or so. that should relate to the gear shift lever only moving a little when in gear.

jeremymilo

Ok, problem solved! Here's what I did to resolve the shifting issues I was having. Thanks to everyone who offered ideas and suggestions.

First, I changed out the rear coupler bushings. This completely solved the side-to-side slop and excess free-play that I had. A good start, but new bushings did nothing to reduce the amount of pressure required to shift out of the "H" towards Reverse/1st.

The solution to excess pressure shifting out of the "H" was adjusting the "shift centering spring" also known as the "preselector spring", "shift operating spring" and "shift operation spring". The centering spring has two functions: (1) keep the shifter in the 2nd/3rd plane when the shifter is "resting" in neutral (although earlier models were designed to rest in the 4th/5th plane) and (2) provide some resistance out of the "H" towards Reverse/1st, mainly to help you stay out of reverse when you don't want it. (Note: the centering spring is not the reverse lockout, even though they have related purposes.) The PO rebuilt the transmission in 2002, and this centering spring preload must have been set way too high, so the stiffness out of the "H" was excessive.

I was able to loosen the centering spring via the threaded adjustment pin on the right side of the transaxle. No need to drop the transmission or anything else. It just took a few counterclockwise turns to create the right shifter feel. The other upshot here is potentially extending the life of the centering spring, which is known to break after extended stresses.

Hooray! Shifting is now very precise and no longer stiff/clunky. You can see the results in the follow-up video below.

mark kibort

yep, that's the ticket!

fraggle

Great follow up, thanks!