Troubleshooting - transmission

[clinem03]

I was underway moving through 1st then 2nd and about to shift into 3rd where I heard a “clunk” and I lost the ability to move when in 2nd or 3rd (I can shift into both but the truck won’t move when I give it gas, it just revs). I could shift into first and reverse but when I’m moving in 1st the trans sounds off, and has a whine to it ( reverse sounds normal) I checked all my linkage and don’t see any issues so I think it’s the trans itself. I had the clutch, fly wheel and TO bearing replaced 3k miles ago but it’s still the OE trans that hasn’t been fully rebuilt. Fluids were changed when the clutch was replaced.

I have a good transmission shop here but thought I’d see if anyone knows what the problem could be since I won’t be able to call them until Monday.

76 wagon, 302, manual 3 on the tree and OE trans

 

[Oldtimer]

Make sure shift lever is bolted tight to shaft.
Next option is shift rail and shift fork aren't playing well with each other.

 

[Broncobowsher]

Inspect the linkage and make sure it is all hooked up.
I've lost a clip once and the linkage fell off the R-1 linkage, only had 2nd and 3rd gears. As long as I could keep rolling it was good enough to get home and fix it.

 

[m_m70]

Inspect the linkage and make sure it is all hooked up.
I've lost a clip once and the linkage fell off the R-1 linkage, only had 2nd and 3rd gears.

X2 on linkage check. Exact thing happen to me but lost 2nd and 3rd like OP.

 

[clinem03]

Make sure shift lever is bolted tight to shaft.
Next option is shift rail and shift fork aren't playing well with each other.

View attachment 885891

View attachment 885890

I assume I need to drop transmission to get to the shift rail?

 

[clinem03]

Inspect the linkage and make sure it is all hooked up.
I've lost a clip once and the linkage fell off the R-1 linkage, only had 2nd and 3rd gears. As long as I could keep rolling it was good enough to get home and fix it.

I checked the linkage first, it’s all connected. Thanks!

 

[Oldtimer]

I assume I need to drop transmission to get to the shift rail?

Yes.

You might disconnect the shift linkage from the shift lever, at the transmission, and shift by hand.
This would verify the problem is internal, before pulling the transmission.

 

[Broncobowsher]

You are really going to want to make sure it is internal before you decide to remove the transmission. Take the linkage off and manually run it through the gears. Put it in 2nd gear via the linkage (remember the R-1 has to be in neutral before the 2-3 will go into gear) and start the engine and see if you are in a gear. If not, you are right and it is internal and you already started getting the transmission out by removing the linkage. If it does go into gear, now you really need to start looking at the linkage and the shifter.

 

[clinem03]

Pulled the 2/3rd linkage, manually put it in 2nd at the transmission started her up, gave her gas and let the clutch out all the way. She didn’t move, nor did she stall out when the clutch was fully released. Must be the shift rail

 

[clinem03]

For historical purposes I figured I’d update the thread on what the issue was. It was a broken output shaft. It literally snapped in 2.

 

[Broncobowsher]

So it snapped between the 1st and 2nd syncros?
How hard did you hit 2nd gear?

Not a common failure. But not unheard of in automotive history as well. Back in high school someone tried to do a burn out (in a Volvo?) and snapped the output shaft. Lost all forward gears. But being a 4-speed reverse was at the very back of the transmission and still worked.

 

[clinem03]

So it snapped between the 1st and 2nd syncros?
How hard did you hit 2nd gear?

Not a common failure. But not unheard of in automotive history as well. Back in high school someone tried to do a burn out (in a Volvo?) and snapped the output shaft. Lost all forward gears. But being a 4-speed reverse was at the very back of the transmission and still worked.

I didn’t shift it hard at all. The shop I took it too has been in business for a long time and specializes in older transmissions. Shop owner said he’s saw a lot of this, just a natural fail point with age