Transmission help

[Dude68]

In process of restoration of 1968 c10, I6 3 speed on column. When it was last running it would jump out of 3rd. A bit of history, it's been in my family since it was new and is all original except engine and transmission swap. I was told that the original Trnsmission was a short shaft and this is a long shaft. That is why the family suspects it is jumping out of gear.

My plans are to leave all of,this the same. The I6 is a 250 and needs a lot of work. My problem is the transmission. It was fine other than jumping out of 3rd gear. Does anyone think this is due to the long shaft transmission. If it is I'll replace with the short shaft.

My build thread is under 1968 redo if anyone wants to look at my mess.

[mechanicalman]

Originally Posted by Dude68

In process of restoration of 1968 c10, I6 3 speed on column. When it was last running it would jump out of 3rd. A bit of history, it's been in my family since it was new and is all original except engine and transmission swap. I was told that the original Trnsmission was a short shaft and this is a long shaft. That is why the family suspects it is jumping out of gear.

My plans are to leave all of,this the same. The I6 is a 250 and needs a lot of work. My problem is the transmission. It was fine other than jumping out of 3rd gear. Does anyone think this is due to the long shaft transmission. If it is I'll replace with the short shaft.

My build thread is under 1968 redo if anyone wants to look at my mess.

I don't think the length of the trans has anything to do with it jumping out of 3rd gear, but no doubt the PRESENT trans that just so happens to have a long tail shaft is having the problem.

Check the shift linkage and verify the shifter rod is moving the shift lever the correct distance to engage the gear, and if that isn't it I'd remove the side cover and check the shift fork for bending/wear or the part the fork goes into (the "dog") for damage/wear.
https://www.google.com/search?q=shif...wQsAQ#imgdii=_

[Dude68]

Thanks

[Lattimer]

IIRC, there is also a ball detent on the side cover that holds the shift fork in place. If that is stuck or the spring under the ball is broken, it may not hold the shift fork in place. Just something else to check.

Those old manual transmissions are really pretty simple. I've had a couple of them apart.

[Bigdav160]

I'd carefully look at the linkage going to the transmission. Wear there is a common problem.

The Muncie 318 is a pretty simple transmission