915 transmission, rear gear sticks

[dirk07]

Got a problem with a 915.

Reverse gear sticks, while I'm able to shift to another gear.

Bushings of the front shift rod, shift rod joint, coupling had been replaced some month ago. New oil, clutch play is correct, position of coupler was set correctly.

Problems that had been detected: the hole in the rear shift rod was worn and a previous owner used a larger screw to bold the coupler to the rod. Looks like to much play at this point. Any chance to fix this without changing the gear shift rod.

I also have to mention that the differential of the transmission had been changed to a locking differential.

Might this be a problem when shifting between the rear and first gear while steering, like parking, too often?

[Jon B]

Rear gear sticks, while I'm able to shift to another gear.

Dirk, by "rear gear" do you mean reverse? And does your transmission lock up if you "shift to another gear" with the rear gear sticking?
It's a common problem for inexperienced builders to misplace a detent in the midcase, but maybe I don't understand the issue you're describing.

Jon B.
Vista, CA

[dirk07]

Hi Jon,
yes I mean reverse gear. Sorry, not a native speaker.
And yes, I was able to shift to another gear and it locks. But after several tries, I cannot move the shift to left or right any longer.

I heard about the dent problem,

Here is a picture of of the transmission build up.



BR
Dirk

[Jon B]

Dirk,

There are tricks for a temporary fix to your problem, but it will happen again if you don't open the transmission and correct the issue.
It could be that a detent is out of position, or that the shift rods were not adjusted properly.

It's early morning here in California, so I'll have to sign off. I'll check back later...

Jon B.
Vista, CA

[gled49]

It sounds like the inter lock pin in the intermediate housing is on the wrong side of the 3-4 shift rail. Removing the plug in that housing will reveal bullet pin on top of the shaft instead of below the shaft where it belongs. Gordon

[Jon B]

Dirk,

Gordon and I are referring to the same thing, in different words. It's one possible reason for your problem.
The pin or detent in question is #4, the 3-4 shift rail or rod is #3 in the diagram below.

You said that you cannot move the shift lever to left or right any longer. Can you still shift into 3rd or 4th gear?



Jon B.
Vista, CA

[dirk07]

Thanks Jon and Gordon,

if detent #4 was mounted wrong, I will fix it only by removing engine and transmission.
Any chance to unlock one of the two gears to have a chance to drive into the garage, which is only 50m away?

Yes, I can still shift into 3th and 4th. Short after the problem occurred I was also able to shift into first.
BR

Dirk

[gled49]

I've done by taking off the side pivot cover and fiddling around, remember to drain oil. It's been a long time so no specifics. If you put the 3-4 shifter in neutral the car should move, probably in reverse, it won't be easy. Maybe Jon has an idea. G

[Jon B]

Any chance to unlock one of the two gears to have a chance to drive into the garage, which is only 50m away?
Yes, I can still shift into 3th and 4th. Short after the problem occurred I was also able to shift into first.

It sounds to us that a misplaced shift detent is your problem, but you might have more than one problem too.
What year is your car? Is the transmission builder helping you with this?

You can try this, if you're transmission is stuck in reverse-

Shift into 4th gear, then push your shift lever to the right and back into neutral. You're trying to pull both 4th and reverse back into neutral at once.
Your shift lever assembly will limit how far you can push the lever to the right while in 4th, so if it isn't working, you can loosen the screws at the shift lever base to give you more push.
You can also disconnect the coupler, at the rear of the tunnel, to do this without the shift linkage limiting your movements.

You can also remove the reverse light switch on the transmission, from under the car, to push the reverse shift rod back into neutral, but the car will need to be on a lift for that.
Even if you get everything working properly for now, it will happen again if you don't fix the problem inside the transmission.

Jon B.
Vista, CA

[dirk07]

Hi,

we got it fixed, but not really repaired. Disconnected the coupler and played with the shift rod and suddenly rear gear was removed. Everything works and we did a test-drive.
My mechanic, who hasn't rebuilt the transmission, took a look inside on a lift and noticed that #3 and #4 has to much play in direction of #2.
We have to open the transmission soon.