grinding gears

[77L130]

I have a 1977 L82 4speed and if I don't delay between shifting from first and second and third to four she will grind the gears . The clutch doesn't slip, so I think its fine.
Any suggestion on what would cause this or if I need to adjust something.

Thanks

 

[69MyWay]

Sounds like you are having a problem with the synchros. They are designed to help reduce the speed of the gears and mesh when shifting. This may be the sign of eventual failure of the transmission.

You can also do a fluid change and make sure that you install the correct weight and viscosity fluid as recommended by G.M. for your model car.

If you have too heavy of an oil, it will be hard to get in gear when cold and could cause excessive wear in other areas. Too thin of an oil, and the trans will make noise and not have enough protection between the moving metal parts.

I would start with a fluid/oil change and go from there.

 

[bradfordsvettes]

if the pilot bushing was hanging up on the input shaft you get grinding gears if the clutch adjustment is not correct not enough throw to disengage properly my last check would be syncros maybe, possibly the brass blocking rings my .02 steve :dance

 

[JohnZ]

Start with the basics - sounds like your clutch needs adjusting; if it isn't releasing fully, you'll overpower the synchros and get some grinding. Takes about ten minutes - you should have about 1" of pedal free play (at the top of pedal travel, with the rubber up-stop bumper in place). Try that first.

 

[69MyWay]

John,

I think you might have nailed it. I converted to a hydraulic clutch on the 69 and totally forgot these things are usually mechanical and require adjustments.

No doubt that will improve the disengage/engage point and allow it to synchro better. A real good test to be for sure that it is out of adjustment is putting it in reverse. If it is hard to start cold and go reverse without double clutching and first putting in another gear then, you will find it is most likely a clutch adjustment problem.

Good call John,


Chris

 

[77L130]

Thanks for your input.

As a matter of fact I do have some problems going to reverse when it is cold, I usually have to double clutch or put it in first gear to get to reverse.

Now my next dumb question is how and where to adjust.

 

[69MyWay]

Look under the hood under the brake booster you will see a threaded rod coming out of the firewall going to a tab welded to teh frame with a rod coming off of that and going over into the side of the block.

You should be able to adjust the threaded part of the rod.