Hard to Shift Transmission

[RWebb]

I have a 1975 915 trans. that is very hard to shift.

It does NOT make a lot of noise (crunching/grunching/grinding/etc.) when shifting as I would expect if the synchros were bad.

What might cause this?

PS - shifter linkage is blueprinted a la Sherwood; newest model shift tower used with SC/RS (factory) SS and the coupler is carefully adjusted.

[911pcars]

Randy,
Clutch fully disengaging?
Same symptoms in all gears?
Does it crunch gears going into reverse?
Upshifts and downshifts?

These questions are for the real gearbox experts, btw. Just trying to help.

Sherwood

[tonythetarga]

Also interested to hear the answer, but, as I understand it, the short shifter on a 915 does make shifting more difficult.

[RWebb]

this is beyond what an old Target short shifter caused - that was likely a 20% reduction; whereas this one is only 10%

I think the clutch is fully disengaging - always hard to tell in a '75... there is no crunching re Reverse

problem seems ot be in all gears & both up or down - maybe less of an issue in the higher gears

[911pcars]

Originally Posted by tonythetarga

Also interested to hear the answer, but, as I understand it, the short shifter on a 915 does make shifting more difficult.

I don't have that experience. Has to do with the gearbox internals and prior driving history.

Sherwood

[robert walsh]

i know this may seem to sound to good to be true, change your tranny fluid with swepco 201, the stuff has solved many a gear box issue, from hard shifting to synchro issues. $49.00 you can't go wrong, unless you know it is a linkage problem, then pass on the idea.

[VaSteve]

How old is the clutch cable? Mine was ready to snap and what was left was stretching I suppose. It got very hard to shift into gear. I just finished changing it and test drove it this morning. Wow. What a difference.

[flatsixnut]

Originally Posted by VaSteve

How old is the clutch cable? Mine was ready to snap and what was left was stretching I suppose. It got very hard to shift into gear. I just finished changing it and test drove it this morning. Wow. What a difference.

I just replaced my cable and it made a night and day difference. Its a cheap and easy enough DIY to make it worth your while to check.

[jorian]

"I just replaced my cable and it made a night and day difference."

I did this and the bushings on my 82' and it made a big difference as well.

[mb911]

I have the same issue in 2nd and 3rd using the same setup you have. I think it is synchros though

[dtw]

How many miles on the trans, and how many of them have you put on (as what I am sure is a cautious and thoughtful shifter) versus the PO? Any rebuild history? Last fluid change? With what? Also, have you carefully examined the pedal cluster, especially at the clutch clevis? A disintegrated bushing there will cause major problems. Clutch cable age and condition?

Many questions .

[pwd72s]

Originally Posted by mb911

I have the same issue in 2nd and 3rd using the same setup you have. I think it is synchros though

I'm afraid I'm thinking the same. But..Randy? Call Gordon...really!

[dentist90]

1. worn (internally, on synchro fitting surface) or missing dog teeth = put synchro ring oversize
2. worn/polished brake bands = reduce efficiency in bringing gear up/down to speed

These can make your tranny balkier. You don't get crunching, as when the synchro bands or slider are worn. Possible causes of reluctant shifting, anyway.

If you can shift into reverse without crunching after waiting about 3-4 seconds with the clutch in it's probably not clutch related.

edit: worn brake bands would lead to crunching, so disregard #2

[Trog]

When in doubt, take it to your trusted P-Car mechanic, and let him take it for a test ride.

[dipso]

I have a 75 with a 915. I was having all kinds of problems too.

Did the swepco, wevo, bushings. Turned out my clutch fork(?) was bending and finally snapped. Hope it's not that bad in your case, prepare for the worst.

It wasn't that expensive to replace.

[RWebb]

clutch cable is brand new; I always use Swepco. There is no trusted PCar mechanic anywhere near here. Portland is a 5 hour roundtrip and it is closest.

miles on the trans = unknown; I have you put on about 40 of them since R&Ring the trans; rebuild history = unknown



Paul - Gordon is definitely on my list (unfortunately, my house is falling apart nearly as fast as I can fix it up..., so I have not calle him as of yet). I would like to drive the car for just part of damn summer before rendering it inoperable again. Plan to take it in this fall.

[dtw]

Your last hope(s) may be a check of the pedal cluster and one more linkage adjustment, but it sounds like it may be near time to open her up.

[JGalt]

I have found that this just appears to be the nature of these transmissions. You have to really pull and push into gear. No crunching, but it does seem to require manhandling, especially when compared to the old 901-911 transmissions. The newer cars are buttery smooth. It spoils you.

[911pcars]

Originally Posted by JGalt

I have found that this just appears to be the nature of these transmissions. You have to really pull and push into gear. No crunching, but it does seem to require manhandling, especially when compared to the old 901-911 transmissions. The newer cars are buttery smooth. It spoils you.

Not at all. The gearbox should go into gear like any other modern gearbox, albeit a little more slowly and methodically than most to not rush the synchros. Shouldn't have to force it if the internals are good.

Sherwood

[RWebb]

I'll add that this one seems much worse than I recall from shifting 2 other 915s in previously owned cars.

Most recently I had a typ 911 trans - I expect the 915 to be less light in feel than the 911.

I hope to drive the car a bit this summer and then let somebody else deal with this. Aftr R&R'ing various trans's about 20 times I've had it.