Transmission won’t shift into third

[Dru27]

Hey I am having problems with my trans shifting into 3rd. All the other gears seem fine. If I do get it into gear then it wants to pop out as soon as I hit the gas. I did notice while in 5th that if I feather the gas pedal just to the point of it engaging the shifter moves with it.
I’m about to Drive from Denver to San Diego and would love to have the 3rd gear problem fixed. Any help is greatly appreciated. Thank you!!

 

[NDT]

Your transmission needs overhaul!! Driving it anywhere is begging for disaster

 

[davidb56]

A good used one is cheaper than a 50 mile tow.

 

[Dru27]

It has all new parts in it that is why i am asking, it was just rebuilt.

 

[davidb56]

Maybe pull the top off and check the shifting forks? They are commonly overlooked in a rebuild for wear. also it would allow you to inspect the "rebuild". Its quick and easy since you can do it from the cab.

 

[Dru27]

Thanks, i had already put a different top on it with new forks and same problem, I am wondering if its something to do with the synchros.

 

[frank8003]

Does it work proper when you double clutch it?

 

[NDT]

Popping out of gear is often related to the gears not being in proper alignment due to internal spline wear on the gear.

 

[Menaces Nemesis]

The shifter moving in 5th is normal, when you put it under load in 5th the shifter tends to move toward the dash, effectively engaging the gear set a little tighter. Davidb56 is right, you need to pull the top cover and see if you can slide that 2-3 synchro in place by hand, and if the synchro detents are working right. If so, then maybe there's something wrong in the top cover with the shift shafts, dogs, and detents. If not, the mainshaft probably needs to come out to see what's going on with that synchro and/or 2-3 synchro hub, which is pressed onto the mainshaft w/2 keys.

 

[Menaces Nemesis]

Other thing is, I wonder if the 2-3 synchro could've been put in backwards. The cones are the same size on both ends, and at first glance it looks like it should go in either way, but one side allows the slider teeth to sit proud of the cone when shifted that direction, while the other side doesn't allow the teeth to get out to the edge of the cone...

 

[Dru27]

Thank you for this advice, I will take a look to see if they were put in backwards it would make sence why it would not shift properly then. I have the old one and was looking at it a bit today the cones are so rounded by looking at it today i didnt know they were cones. I will take a look tomorrow if the weather holds out and isnt blowing hard. I can deal with a little snow.

I see you live in Denver im up in Blackhawk.

Other thing is, I wonder if the 2-3 synchro could've been put in backwards. The cones are the same size on both ends, and at first glance it looks like it should go in either way, but one side allows the teeth to sit proud of the cone when shifted that direction, while the other side doesn't allow the teeth to get out to the edge of the cone...
View attachment 789869View attachment 789870

 

[Menaces Nemesis]

You're welcome. The brass parts are usually referred to as "rings" but they have a conical braking surface. Whatever the problem ends up being, I hope it's an easy fix

 

[frank8003]

Say what lubricant is in transmission/transfer case.
May want to re-tighten all the jack shaft bolts while you have the floor plates up.
Those fasteners are grade 8 with grade 9 nuts, notorious for loosening.
May want to do the GAA grease PM on all those zerks down in there.

 

[Dru27]

Flipping the 2/3 synchro did the trick at least during the test drive everything was shifting fine. I really hate the little barrel barrings though! Its all back together though. Thank you for the tip on that again.

You're welcome. The brass parts are usually referred to as "rings" but they have a conical braking surface. Whatever the problem ends up being, I hope it's an easy fix

 

[gringeltaube]

Flipping the 2/3 synchro did the trick at least during the test drive everything was shifting fine.

If it really was in, backwards then you could not have any synchro action at all in 3rd, so it was always grinding to engage?