TK4 won't go into gear after TO bearing replacement

[dwhile]

Old throw out bearing was making quite a racket. Dropped trans and replaced the bearing. Then, I had issues with old clutch cylinders. Replaced them, then had issues bleeding the system. Built a power bleeder that did the trick. Now, upon starting the truck and attempting to back out of the garage, it won't shift into gear. I can shift it into reverse with the engine off, but once it is started it won't shift. It'll grind if I attempt to shift into reverse with the engine running, but no other gear gives any grinding. Just won't shift in.

My thoughts :

- I incorrectly installed the throw out bearing
- now the entire transmission must come off again

If someone could tell me I'm wrong, I'd be a happy camper. As is, I have a third week of no daily driver. Sharing a car with the wife is getting old. Any suggestions?

 

[Denisefwd93]

Take the rubber cover plug on the bottom left of the transmission bell (driver side) have somebody push the clutch pedal down (with the wheels blocked for safety) and watch and see if the TO moves the clutch in and out.

I may be wrong about your transmission bell housing but most have some way to look inside.

 

[dwhile]

Will give this a shot tomorrow morning. I've been working on this truck every spare minute I have for the last two weeks and I'm about to lose my mind. Thanks for the response!

 

[RonD]

Just to be clear ".... no other gear gives any grinding" but you can shift into those gears, i.e. 1st, 2nd, 3rd....?
Just can't shift in to Reverse

The other gears have synchromesh its a softer metal gear that slows down or speeds up the input shift gear so it meshes with Dog gear without grinding

Reverse in the TK4 doesn't have synchromesh, so can grind unless input shaft(clutch disc) is at 0 RPMs when you try to shift into Reverse

If Reverse grinds that means the clutch disc/input shaft is still spinning when clutch pedal is pushed down all the way

Engine idles at say 650RPMs, so when clutch pedal is up then clutch disc/input shaft is spinning at 650RPMs as well.
When you push down on the clutch pedal the pressure plate should retract so clutch disc is no longer pressed against the Flywheel
This allows the clutch disc to slow down to 0RPMs
If there is not a FULL release of pressure then clutch disc will rub on flywheel so it can't slow down to 0RPMs
If clutch disc is not at 0RPMs and Reverse gear IS AT 0RPMs(rear wheels at 0RPMs) then you will hear grinding when you try to mesh input shaft(clutch disc) to output shaft(reverse gear)

Was old throwout bearing same thickness as new one?

 

[dwhile]

Pardon the lack of clarity. It will not shift in to 1, 2, 3 or 4. Doesn’t grind when I attempt to shift into those gears. It does grind when I try to shift into reverse.

 

[dwhile]

I think new bearing was nearly identical to old one. No discernible difference in dimension.

 

[Denisefwd93]

That's a pretty common problem when the shaft is still spinning it won't go into gear, did you replace the pilot bearing? my Pontiacs didn't have one. Anyway before you tear things apart, you want to at least make sure the pedal moves the bearing in and out before you start taking the truck apart again.

 

[dwhile]

Thinking I can remove starter and stick my phone in the bell housing with the video recording to see whether or not the clutch is engaging. I did not replace pilot bearing, I drove it for about a month before starting the throw out bearing replacement with no issues other than squeaking from throw out.

 

[RonD]

Yes, then that makes sense, that it won't go into any gear
The slave inside the bellhousing is not pushing against the pressure plate hard enough to release the clutch disc fully.
And the synchros on 1-4 stop them from grinding but if clutch disc can't slow down to 0 RPMs then it can't be forced into a 0 RPM gear


Be careful, put trans into 1st, engine off, then start engine, foot HARD on the brake
If engine won't start, turn over, then clutch disc is not releasing AT ALL, so slave is not working, expanding

If engine starts but truck wants to move forward then clutch disc is only being partially released by slave, so air in the system most likely

 

[dwhile]

I also dropped the clutch pedal bushing and was unable to find it, so I know i could have an additional 1/8 inch of push on the master too if I installed a busing on the master cyl rod.

I really appreciate the responses everyone. I’m hopeful that I won’t have to drop the trans again. Will see what the situation looks like in the morning.

 

[dwhile]

Little update. Put the truck in 1st while engine was off, then started the truck with my foot heavy on the brake. Truck tried to move forward, which tells me that I need to continue bleeding.

 

[RonD]

If the engine started when in 1st then slave is working, just not pushing pressure plate "fingers" in far enough.

And you are correct, that clutch pedal bushing could make the difference, master needs full travel to get full travel at slave

 

[dwhile]

After some more bleeding, issue persists. The local Napa is closed today, but I work there so I’m going to run up and grab a bushing.

 

[alwaysFlOoReD]

I'd be interested in seeing your power bleeding setup.

 

[Denisefwd93]

A friend of mine gave me a mityvac to try out a few years ago. I'd venture to guess it's saved me several thousand dollars.

as I understand it, the installed angle of master cylinder traps a small bubble of air that's almost impossible to remove unless you turn it upside down, l good luck with that.

I will always opt for the pre bled setup which doesn't cost any or much more then the components separately.