915 Transmission - Can't Get Into Reverse Easily when Warm

[OsoMoore]

I recently replaced my transmission fluid (a late follow-up change after a rebuild 2 summers ago).
Now I have a problem where, when the transmission is warmed up, the reverse gear is spinning too fast to engage reverse. It has no synchro, so I have difficulty getting it into reverse gear without grinding. Everything else seems to be working well. I'm not sure if the fluid change is related - hot summer weather began at about the same time.

Is this likely a sign that I need to replace my clutch? Or is it probably just a clutch adjustment issue?

I found another thread (Another clutch issue thread) that seemed to indicate an adjustment was in order for a similar issue.

This is getting awkward in public - everyone looks at you funny when you can't seem to drive your fancy car properly.

[jpnovak]

sounds like your clutch is not releasing fully. You should be able to push the clutch in, count to 5 and then engage R without any grinding.

Have you adjusted the clutch properly?

[OsoMoore]

Originally Posted by jpnovak

sounds like your clutch is not releasing fully. You should be able to push the clutch in, count to 5 and then engage R without any grinding.

Have you adjusted the clutch properly?

I adjusted it two summers ago following the Bentley instructions, but I haven't checked since. I'll go ahead and do that next. Thanks!

Here's another thread I found which indicates I should also check my pedal roll pin (Clutch Fork Broken or Adjustment Problem?).

[OsoMoore]

I hoisted her up and found the source of my problem last night.

There are two bolts which hold the clutch cable sleeve's end on the bottom of the transmission. The pedal-side bolt had backed off about a centimeter, and as a result thrown off the clutch adjustment. Pushing the pedal to its stop didn't fully disengage the engine.

At first I didn't see this. I took out the board above the pedal cluster and adjusted the bolt between the levers. With this extra clutch distance, I was able to engage and disengage. Then I spotted the backed-off bolt (in red).


After pulling the sleeve back into position, I was able to fully disengage the engine with the floor board back in place.

I still need to adjust the floor stop, as the pedal motion is now overly long. But pushing down the clutch is now fully disengaging the engine and I am shifting better than ever.

[DRACO A5OG]

Oh congrats.

I always try to consciously stop the gears before going into 1st or reverse by tapping 2nd. Just good practice for our delicate 915s

[Pstallo]

What do you mean, stop the gears by tapping second'?

[DRACO A5OG]

Not literally stop but by just touch the other gears, it is enough to slow the gear box down enough to allow a smooth "IN" to a gear, especially reverse. Try it.

Start the car, clutch in then go to any gear but not all the way in, "just the tip" ;-) then go to Reverse. It will just plop right in.

When I test drive my buddys' cars and know that they have some gear issues, I always do this so I do not grind gears. So far so good

[OsoMoore]

"Touching" the gear basically engages the synchro ring against the shift sleeve but doesn't compress the synchro or bring the dog teeth into engagement. Reverse doesn't have a synchro ring, so you are "borrowing" the synchro from another gear. It might be easiest to "borrow" 5th's because it is faster to swap back to reverse, and 5th probably sees less use anyway.

I've found that with my shift adjustment, the shaft isn't moving at all after I fully clutch and pause a couple seconds.

It is amazing what a proper adjustment can do for the shifting feel.

[DRACO A5OG]

:-D I like that explanation better and like the idea of borrowing from 5th, makes sense.