Odd 915 problem - 3rd-4th bad. 2nd-4th great?
 

Ok, I've searched the archives and although we all know there's a ton of stuff out there on the 915 transmission and shifting issues, I haven't found anything on this. On my '81 SC, I occasionally have problems getting into 4th. It feels like the transmission is blocking the movement and even with a little rowing around, moving it towards 3rd, then back to 4th, it only goes in with a lot of force or a long wait. Feels just like bad synchro.

I've replaced all the shifter and coupler bushings, new Swepco fluid (which changed nothing at all). Other gear transitions are great. I've spent a fair amount of time adjusting the coupling and I think it's right. The car had 1st and 2nd synchros replaced around 100K (car now has 144K)

Now, here's the odd part - If I shift directly from 2nd to 4th, it's smooth as butter every time. It's actually quite reasonable to drive the car this way but something isn't right. Do I need to fiddle with the coupler even more? I'm reluctant to do that because all other gear changes are great (well, at least as great as a 915 can be!)

mike

Mike, this sounds like adjustment to me.... how does it feel to go from fourth into neutral and then back into fourth? Do you notice any binging in the linkage or can you feel that you are hitting the gate on the shifter?

One thing I noticed with 915 is that when you shift after lots of load the engine/transmission packages "rotates" in the car. This makes shifting difficult. Shot or worn engine/transmission mounts make this worse. You might want to replace the four mounts with sport mounts. This will help to better locate the gates on the 915.

Cheers,
Ingo

I'll have to try to 4th to neutral to 4th test. The gearshift does feel like it's hitting the gate in all gears, that's one reason I haven't fooled around with the coupler adjustment. I've considered replacing the transmission/motor mounts but haven't come up with a good reason to other than the fact that they're probably 26 years old.

I've never understood why people suggest replacing the mounts to improve shifting but your description makes sense. I just assumed the engine/transmission where a solid unit but of course the shift mechanism is attached to the chassis and not the engine/trans. so any difference in relative the location changes the angles.

thanks,

Mike

Mike,

the 26 years are an excellent reason to replace them..... and you are right, the entire entire engine/tranny package is "located" by these mounts. Load changes will move and twist the package. As a result the rotational adjustment of the shift coupler is off once the position of the engine/tranny package is disturbed.

Cheers,
Ingo