Gearbox Grinding

[Scotty]

From what I understand the 80/90 gear oil contains something like sulphur which will destroy
the brass synchros in a Rootes transmission. Perhaps, and especially since the car was sitting for a while,
is what happened and why you're getting some grinding.

The 80/90 was put in by the shop that rebuilt my brakes and installed the new MC/SC. When the Gearbox was rebuilt and left sitting, it had 30W in it, same as the engine. Had to dig up my receipts to check that. Sorry gang, I'm still running slow, my hand's been bugging me again :/

 

[RootesRooter]

Sitting with 80/90 in the gearbox isn't going to make it suddenly "grind." It might grind if all that 80/90 had leaked out of a worn rear tranny seal, but you or the mechanic would have noticed a wide, thick puddle on the garage floor.

This is about the clutch. It's grinding when you attempt to shift. Almost certainly hydraulics. Dark-horse candidate is that the mechanics managed to do more than just break the stuck clutch free of the flywheel, like a broken clutch plate spring.

 

[bulldurham]

Most up to date 80-90- gear oils have buffers to prevent yellow metal corrosion.
No idea how that will hold up over time but Redline, Royal Purple make a blend specifically to use in trans
units. Next time I service my J-type OD that is what I will be using.

 

[todd reid]

This is a long shot, but I always like to check the easy stuff first. Check that the bolts that connect the remote shift mechanism to the transmission are tight (and have lock washers). If they vibrate loose it can give you the symptoms to are experiencing.

 

[Scotty]

This is a long shot, but I always like to check the easy stuff first. Check that the bolts that connect the remote shift mechanism to the transmission are tight (and have lock washers). If they vibrate loose it can give you the symptoms to are experiencing.

Mine were very loose... just tightened them. Going for a long drive tonight and hoping this is what it is.

I have checked everything. I have oil in the gearbox, I did the clutch pedal 'test', I took everyone's advice. I'm going to see tonight if it grinds again and if it does, I'm considering yanking the gearbox and seeing what's going on.

Thank you all for your time, aid, and advice. I'll post more after tonight's run. I intend to drive the car on the freeway today since I've done a ton of short runs and I'm starting to think these are bad for the car. I drive the car around town and don't do any freeway travel at all.

 

[Scotty]

Just wanted to wrap this up. Took the car for a long drive last night, ran it on the freeway and it went very well. No grinding, no issues. If it pops up again, I will definitely post but at this point if it does, I may have the gearbox removed and have it and the clutch checked thoroughly. Thanks so much gang for keeping us on the road!!

 

[husky drvr]

If the top cover was loose, then your grinding was probably caused by the shift rail's misalignment trying to engage two gears at the same time.

You've probably solved the problem.

Congratulations,

 

[Gordon Holsinger]

From what I understand the 80/90 gear oil contains something like sulphur which will destroy
the brass synchros in a Rootes transmission. Perhaps, and especially since the car was sitting for a while,
is what happened and why you're getting some grinding.

80 -90 is too thick and drags transmission gears