Three speed whine in first gear. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ronw435 · 09-13-2015, 10:03 AM

Was wondering if anyone knows if the non synco three speed in our trucks whine quite a bit in first gear? Or am I going to have to take it out and rebuild it? Were they kind of noisy?

Thanks
Ron

**Jurassic-1** · 09-13-2015, 10:50 AM

My truck is pretty quiet. Have you checked the fluid level or condition? Look for any signs of metal in the oil.You may want to change the oil in it if it has not been done in a while.

Ronw435 · 09-13-2015, 10:58 AM

Yeah I drained and refilled the transmission before I put it in. Probably will have to rebuild it. Thanks for the reply Jurassic. The PO had also had the transmission flushed and filled. It was very clean when I drained it.

Ron

Ronw435 · 09-13-2015, 11:09 AM

Jurassic is yours the non syncro first gear? 4 bolt side cover?

Thanks again.
Ron

Ronw435 · 09-13-2015, 11:10 AM

Anyone know of a good rebuild kit for these transmissions?

**jayoldschool** · 09-13-2015, 11:30 AM

I'd have a quick look at gear pics before worrying. I'll bet the 1st gears are a little more straight cut, and that gives whine. Compare the gears on an M21 and an M22 and you'll know immediately why the M22 is noisier. Reverse gears, too. Straight cut means whine (and higher power handling, that's why they're straight cut).

**Palf70Step** · 09-13-2015, 01:30 PM

Quote:

Originally Posted by Ronw435

Anyone know of a good rebuild kit for these transmissions?

I know in our area it is hard to find someone who works on manual transmissions. I got lucky when I needed to do the one for my 64 (it's out of a 69 truck though) The same guy that rebuilt my munice 4 speed in 1974, got to rebuild this on. He is in his 80s though.

Good luck. It sounds like yours in the non-syncro 1st gear and the whine may be part of it. I have not driven one of those trannys in a VERY long time. Good luck with it.

**Jurassic-1** · 09-13-2015, 02:41 PM

Yes mine is the non syncro one. I got another one from a 67 GMC and hoped it was the syncro one. It had about 62000 original miles on it. It turned out to be the same one as mine. I am considering a 250R automatic. My problem is the throttle pressure TV cable. No one seems to make the adapter to get the cable geometry correct for a 6 cylinder. I may try to make one. My wife has a problem driving the 3 on the tree smoothly.

cv65 · 09-13-2015, 03:10 PM

Quote:

Originally Posted by Ronw435

Anyone know of a good rebuild kit for these transmissions?

you may need gears when you open it up you should see if just a bearing heres a kit http://www.ebay.com/itm/GMC-Chevy-Mu...77e203&vxp=mtr

09-13-2015, 10:03 AM	#1
Ronw435 Registered User Join Date: Apr 2014 Location: Fate, Texas ( About 35 miles east of Dallas) Posts: 318	Three speed whine in first gear. Was wondering if anyone knows if the non synco three speed in our trucks whine quite a bit in first gear? Or am I going to have to take it out and rebuild it? Were they kind of noisy? Thanks Ron

09-13-2015, 10:50 AM	#2
Jurassic-1 Registered User Join Date: Jul 2007 Location: New River Arizona Posts: 1,180	Re: Three speed whine in first gear. My truck is pretty quiet. Have you checked the fluid level or condition? Look for any signs of metal in the oil.You may want to change the oil in it if it has not been done in a while.

09-13-2015, 10:58 AM	#3
Ronw435 Registered User Join Date: Apr 2014 Location: Fate, Texas ( About 35 miles east of Dallas) Posts: 318	Re: Three speed whine in first gear. Yeah I drained and refilled the transmission before I put it in. Probably will have to rebuild it. Thanks for the reply Jurassic. The PO had also had the transmission flushed and filled. It was very clean when I drained it. Ron Last edited by Ronw435; 09-13-2015 at 11:08 AM.

09-13-2015, 11:09 AM	#4
Ronw435 Registered User Join Date: Apr 2014 Location: Fate, Texas ( About 35 miles east of Dallas) Posts: 318	Re: Three speed whine in first gear. Jurassic is yours the non syncro first gear? 4 bolt side cover? Thanks again. Ron

09-13-2015, 11:10 AM	#5
Ronw435 Registered User Join Date: Apr 2014 Location: Fate, Texas ( About 35 miles east of Dallas) Posts: 318	Re: Three speed whine in first gear. Anyone know of a good rebuild kit for these transmissions?

09-13-2015, 11:30 AM	#6
jayoldschool Moderator Join Date: Dec 2012 Location: ON, Canada Posts: 2,176	Re: Three speed whine in first gear. I'd have a quick look at gear pics before worrying. I'll bet the 1st gears are a little more straight cut, and that gives whine. Compare the gears on an M21 and an M22 and you'll know immediately why the M22 is noisier. Reverse gears, too. Straight cut means whine (and higher power handling, that's why they're straight cut).

09-13-2015, 02:41 PM	#8
Jurassic-1 Registered User Join Date: Jul 2007 Location: New River Arizona Posts: 1,180	Re: Three speed whine in first gear. Yes mine is the non syncro one. I got another one from a 67 GMC and hoped it was the syncro one. It had about 62000 original miles on it. It turned out to be the same one as mine. I am considering a 250R automatic. My problem is the throttle pressure TV cable. No one seems to make the adapter to get the cable geometry correct for a 6 cylinder. I may try to make one. My wife has a problem driving the 3 on the tree smoothly.



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