Odd thing happened today out of the blue. Went to shift into 3rd and it grinded. Then it did it again and every time I shifted into 3rd but not any other gear. Thought maybe the floor mat had slipped up behind the pedal, but it didn't and the clutch Reservoir was full.
Could be your third gear has a bad spot on it and needs replacing.
Do the things you can that are easy and cheap. Check the oil. Is it full? If you don't know when it was last changed, maybe time to replace it. There is a good read ....
You can buy it under the GM label AC DELCO CDN part number : 10953509... AC DELCO CDN part number : 10953509.
Ok good idea, Now if I can find AC DELCO Synchromesh Manual Transmission Fluid 10953509. Found some ACDelco 10-4014 and ACDelco 10-4006?
The ACDelco part number: 10-4014 is the exact same thing as AC DELCO CDN part number:10953509.
The part numbers are just different, the 10-4014 is the US part number while the 10953509 is the Canadian part number.
Great, thanks. I will pick up a couple quarts.
FYI, when I bought my truck last year I changed fluids in both diffs, transfer case and MT with Royal Purple. I put about 3K on the truck(220K miles), the MT had shavings and one piece of metal. The Syncros are OK but have wear( no grinding ). I decided to drain the MT to replace a seal and refilled with AC Delco Synchomesh 10-4014. It amazes me how much better the formulation is for this truck compared to Royal Purple. Thanks for the input!
Ok had to special order the AC DELCO Synchromesh Manual Transmission Fluid, I am draining out the old oil now. I was surprised to see the old oil wasnt low.
Anything stuck to the drain bung magnet that shouldn't be there?
The plug didn't have anything unusual on it, No chunks or anything. Minimal fillings if any, I did have the Transmission oil changed at 50,000 at VIOC a few years back when I had the money and would get my oil changed there. Learned my lesson after they broke my oil pressure sensor on my truck and blew up my engine on my car
Update 1/10/16. Still no change, Guess its damaged. Could using the wrong gear oil cause this problem? Back when I had money and no time I would go to Valvoline instant oil change and I had them change my gear oil. Would they have put in the correct oil or have used what ever they have on hand?
I think you answered your own question in the last 6 words.
Most shops have no clue that you must use brass safe gear oil in these trucks.