75/5 Jumps Of Gear

[schrader7032]

Stephen -

So you're saying that you're working your way up the gears, say, you shift to second, let clutch out, roll on the gas, speed up enough to shift to third, let clutch out, and then what happens? Does third not engage or does it engage, you roll on throttle, and that at some point during the acceleration, it pops out of third? And, if you get to fourth, shifting the tranny, letting the clutch out, and accelerating...no problems in fourth?

What about coming down in gears?

I wouldn't think it's adjustment of the clutch cable if the other gears are working OK...no grinding, etc. One thing it could be is your technique. I used to "miss" gears or get false neutrals on my /7 going into 4th or 5th. I learned to continue to hold up pressure on the foot lever as I let the clutch out. That has virtually eliminated the false neutrals, unless I get too quick with the shifting process.

Otherwise, it sounds like that the mating portions of the gears, I think it's the dogs, are rounded and won't stay together. I think it's like a ring of holes on one piece and the mating piece has a ring of protrusions which are supposed to engage the holes. The protrusions/holes should be fairly square cut...if they're rounded, they tend to slip. Duane Ausherman has a picture of these on his website, about 1/3 of the way down on this page:

http://w6rec.com/duane/bmw/trans/

Read over this page and see what Duane has to say about it. You might be looking at an overhaul.

Kurt in S.A.

[childs7480]

Kurt,

Thanks for the information, I will try making sure the gear goes into third, not neutral and if that fails I will change up at 4000 rpm and save the cost of a rebuild!!

There is no problem on changing down or any other gear.

Stephen

[VBMWMO]

Help. My 1972 75/5 is jumping out of third gear when I get to 4000 to 4500 rpms. The gearbox works great otherwise.

Any one got any ideas?

Thanks

Stephen