Transmission grinds going into L or R

[84K30]

1984 Chevy K30. 454. NP435. NP205. 33k on the clock. It has definitely turned over at least once. I have put about 8k on the truck since I purchased it in 2019.

Recently, my transmission has been grinding when I shift to Low/1st or Reverse. I adjusted the clutch (mechanical linkage) and the issue was resolved...until I drove it a few miles and the symptoms resumed. This seems to be a recurring phenomenon. The transmission goes into all of the other synchronized gears without issue. I do not hear any strange noises. The clutch pedal sometimes shudders while driving. Sometimes the transmission will go into Low/1st without grinding if I shift into 2nd gear beforehand. Other times, I've had to kill the engine and drift the truck a few inches in neutral for the teeth to mesh up before restarting.

Any ideas what might be going on? Is my clutch shot? Thanks.

-Eric

 

[85K304SPD]

So your truck has the 4 speed overdrive transmission ,NP A 833, or the 4 speed with the granny gear low? SM 465

 

[WebMonkey]

that was my first thought
sm465 L and R are unsync'd and do that all the time

 

[fast 99]

Clutch likely not disengaging if there is free play on top.

 

[84K30]

Transmission is a SM465. Sorry for the confusion.

 

[nvrenuf]

sm465 L and R are unsync'd and do that all the time

This ^^ Normal operation.

If it’s always done it but now it’s worse, the clutch likely needs to be adjusted.

 

[85K304SPD]

If you are not moving, with the clutch in, they should not grind. If you are trying to get it into L or R with it rolling, they will probably grind a little. If they grind when you are not moving, your clutch will probably need adjusting or replaced.

 

[TotalyHucked]

Could be time for a clutch or could be worn synchros. A couple of my previous mustangs would do that, had to go to 2nd or 4th before reverse cuz of worn synchros

 

[84K30]

This is occurring while stationary and has not always been the case. I’ll try adjusting again and start looking into a new clutch. Thanks!

 

[DoubleDingo]

If adjusting the clutch doesn't help, replace the clutch. Unsynchronized gears always grind a little bit. But if they grind and you can't get them into gear, the clutch isn't disengaging enough for the input shaft to slow down. If you replace the clutch, get the complete clutch kit that comes with the disc, pressure plate, and throwout bearing. And don't forget to get your flywheel resurfaced while you're at it.

 

[SquareRoot]

Remove and replace with NV4500. Report back.

 

[84K30]

Update: It was a clutch adjustment issue. Sought the assistance of a buddy who is more knowledgeable and competent than I and we got it resolved. Thanks for your assistance.

 

[viaminveniam1939]

What was the solution?

 

[DoubleDingo]

What was the solution?

He adjusted the clutch