diagnose this please

[BLUNT]

1969 4 speed all stock

car in neutral idling i have a terrible grinding noise. push the clutch in it goes away. 1st,2nd and 3rd gear i get the same noise while driving. put it in 4th and its silent. i changed tranny fluid for the hell of it and dumped MTL in it. the drain plug (magnetic) had a shitload of metal on it but the fluid didnt look real metallic at all. im assuming its the throw out bearing but im puzzled why it goes awy in 4th. car shifts fine and no grinding between gears. any thoughts??

[Michael_B]

From what you describe, I would tend to come up with the same thought of the throw out bearing. My TR6 had a similar problem and that's what it turned out to be. The fork was held in place between two shafts by a pin that had sheared off allowing the forks to move forward and engage the bearing just enough to be spun by the pressure plate. It eventually spun all of the grease out of the bearing and started to make a whirring/grinding noise. When i pulled the transmission out, there was a "halo" on the inside of the bellhousing from all of the grease. To be certain that the t/o bearing was the problem I put the car up on jack stands and with the car in neutral and running, would manually move the clutch arm until the noise would appear. Then I unhooked the slave cylinder so that I could move the arm back far enough tho make the noise dissapear completly. I can't remember if he noise went away entirely in higher gears like yours does.

[c.d.iesel]

if the collection of crud on the magnetic

drain bolt was very fine and pasty - that's somewhat o.k.

but if harder, larger metal bits are there - start saving for a trans.

... also suspect a flywheel piliot bearing with the throw-out bearing

[Pinepig]

I'm not thinking throw out bearing because of the 1st 2nd and 3rd thing. In 4th the tranny is in a 1 to 1 gear mode and bypasses most of the gearset in the tranny. I'm thinking the problem is internal and not the TOB.

[gone002]

check your syncros

i had the same problem

worked fine in all gears but 2nd

at the time i could not afford new ones

so i had the 2nd and 4th switched

and the grinding went away

goner-

[Marty]

I agree with Pinepig my guess is your layshaft bearings are going away when the tranny is turning the layshaft makes a grinding/rattling noise in 4th gear you are running direct and the layshaft is bypassed.

[trangieboy]

Layshaft and/or input shaft bearings.Get a 5 speed.

[BLUNT]

thanks guys, figures i just got rid of my spare 4 speed too. ill yank it and confirm and then start looking for a spare. i dont want to do a 5 speed because this was suppose to be a low budget driver project. if i start ill never stop and ill have 2 money pits

[Mike Self]

and the chunks you got out of the case are pieces of bearing race. On my 4 speed it was the ball bearing on the layshaft...Later trannys used a tapered roller bearing as that shaft gets some radial thrust and ball bearings don't like radial thrust. Bearing is inexpensive, but a PITA to replace; used trannys are easier and more plentiful...

mike

[Pinepig]

thanks guys, figures i just got rid of my spare 4 speed too. ill yank it and confirm and then start looking for a spare. i dont want to do a 5 speed because this was suppose to be a low budget driver project. if i start ill never stop and ill have 2 money pits

I'll throw a four speed in my trunk for Palo Alto, yours for 40 bucks, you just have to schlep it back with you.

[JP/A-1]

hey blunt it's the lay shaft bearings making noise.

you will have to rebuild or just fine auther transmission.

jp