Yes, but make small, I mean real small adjustments. You are moving the shift lever aft, thus making the throw a tad longer. Its what I did, took a while because as we all know, its fickn hard to not move the coupler left and right while doing this.

Glad to help. I actually happen to have my '86 915 on the stand since the engine is out for repair. So I took the tail case off the trans because it's easy to remove and we can all see what's going on with the operation of 5th and reverse.

Turn up the volume to hear my comments on the video. Sorry for the shaky video but i'm holding the iPhone with one hand and trying to operate the main shift rod with my free hand

https://www.youtube.com/watch?v=lTLh75Uldoo

Basically it goes like this:

• The video starts out with 5th gear already engaged.
  
• To select neutral I have to yank on the shift rod with a plastic T-handle and that forces the brass shift fork (which is always fixed in place sitting in the valley of the shift sleeve) to move the shift sleeve to the right.
  
• It then pops out of 5th and sits in neutral. When it falls into neutral, look up and to the right at the double gear above. This gear looks like it's dangling there doing nothing. This is the reverse idler gear. This is a double gear because it's all one solid piece joining the two gears via the center hub (hub has the number 481...... something scribed on it) and there's a shaft passing through the hub that allows it to rotate.
  
• Sitting in neutral you can see the large blunted teeth on the right side of the shift sleeve are quite close to the double gear's right side blunt teeth. These blunt teeth are how reverse is engaged, which is very different from the synchronizer parts that the forward gears have. Instead of having a friction band and pointy teeth like the forward gears, reverse is unsynchronized and simply uses rounded teeth that will fall together when the shaft speeds are slow enough- basically when they're not spinning. When they're spinning too much, they grind. A lot of us recognize this grinding as pushing in the clutch and then selecting reverse too soon. The gears grind because the rotating shafts have not yet stopped spinning and the blunt faces just bang against each other and don't want to fall in place.
  
• When I pull the shift rod all the way out reverse is fully engaged by the meshing of the fat teeth. You can see it takes a lot of shaft movement for reverse to fall into place.
  

So it's possible that the shifter is in need of some adjustment and maybe you have an issue with the clearance between the reverse gear teeth being quite a bit closer than what you see inside my transmission. Since your transmission has been recently rebuilt, maybe the builder didn't properly set the clearance right between the idler gear and the shift sleeve. The factory manual calls for a small window of 1mm clearance between them



http://forums.pelicanparts.com/uploa...1520630759.jpg
http://forums.pelicanparts.com/uploa...1520630759.jpg

^^Post of the year! PERIOD!

Thanks for taking you gearbox apart to get us some insight. That’s what thisnforum is all about.

No problem. Glad to help because it keeps my memory fresh about the 915 details.

The plan is to take the 915 apart anyway because I have some gears I want to swap in, as well as install a one piece bearing retainer. However I told myself I wouldn't dig into the trans until I get the engine back in order.

I'd suggest doing some adjusting at the shift coupler and see what that does. Get a helper to hold something so you can adjust it as precisely as possible. The fellas are 100% correct that a tiny adjustment of the coupler does a big change.

Last fall I had discovered my reverse lockout teardrop on the shifter wasn't engaging. I was able to engage 5th no problem but it wasn't going far enough upward to pass the teardrop. So I could have selected reverse coming out of 5th if I wasn't careful. I adjusted the coupler a bit, checked for gear selection in the garage with the engine off, then started it up and rolled out of the garage to go for a drive.

I rolled forward down the driveway since I had the car backed into the garage. When I got into the street I needed to use reverse for some reason. Couldn't get reverse to engage at all! Turned around and went back in the garage readjust. So my point is that what seems like slight adjustments at the coupler make big changes at the shifter and vice versa.

So I got some time to myself this morning with some open road and good turn off points for adjusting. I made 4-5 incremental adjustments about the size of a fine point felt tip sharply. I knew I had gone to far when second would pop out. I figured that was my outer boundary and made a hairline adjustment foreword. All seemed well. When back home I changed the spring on my WEVO on the drivers side to stiffen up the return to neutral as I come out of 5th.

I’m curious on how all this feels on a cold gearbox.

Thanks again for everyone’s insIght and shared struggle.