C3Paul

Hey Guys

Need a little help, pls.

Gearbox is making really bad crunching noise when selecting reverse.
This only happens after the car is fully warmed up and only when selecting reverse.

No issues with forward gears, or when cold.

While selecting the reverse you can feel the resistance from the gearbox.

Just really confused why this only happens when hot and only reverse.

Thank you

gkull

Try adjusting the zbar for additional throw out bearing clearance if not a hydraulic clutch

C3Paul

I have been thinking that it has to be something Clutch related, but why only the reverse and not forward gears?

1969 for 50 years

No syncros for reverse?

gkull

I have not rebuilt a tko 600 to verify it, but many trannies don't use synchros on the reverse gear to help the gear mesh

So the main shaft is spinning and the reverse gear is stationary

C3Paul

That makes sense
if the throw out bearing isn’t disengaging properly it will allow the gearbox to spin and not allow selecting reverse?

CanadaGrant

I don't believe there are syncros on reverse. Try going to either 1st or 2nd gear and from there straight to reverse and see if it stops grinding.

C3Paul

tried that, made no difference

C3Paul

Btw, it’s just standard BW Super T10 4 speed

CanadaGrant

Then I would look at either the throwout bearing or clutch adjustment as something is allowing the input shaft to turn slowly.

JBrooke825

first then reverse always.

CanadaGrant

Yup!

Rescue Rogers

If first then reverse isnt working and it doesnt do it when the oil is thick and cold I would try adjusting the clutch and checking the fluid level. I would also check to see what condition teh oil is in while you hae the plug out. If it hasnt been changed since it was new then it could be time for a change.

74_stingray

This will very likely fix your issue, a bit of adjustment makes all the difference and it’s easy to do.

stingr69

You need 1" of pedal free movement under finger pressure before the linkage slack is gone. You can check that first. Put transmission into a forward synchronized gear before trying to go into reverse will stop all the gears from rotating if everything is right with the setup.

If it is too much slack in the clutch linkage from bad adjustment, the clutch will not release fully. The disk (and gears) will continue to rotate with the flywheel and the reverse gears are trying to mesh while only one of them is rotating so you get the grind.

If the slack is too tight the clutch may slip under load and that causes lots of heat which cooks the clutch. Warpage from heat will cause the disk to not release fully with the same result as above. The clutch will need to be replaced not due to wear but due to warpage. Can not adjust it away.