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Old 03-18-2019, 09:44 PM   #1
67ranchhand
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67 sm420 question

Hello everyone. Got the dual exhaust put on today at the muffler shop and finally got to drive this thing! It drives real nice and good power for a stock 327. My question is, does this trans or the t case usually whine? It’s not loud but you can hear it whine. I changed all the fluids in everything and all the old gear lube looked fine but with no exhaust before, I never heard it. Just curious if this is normal for these or do I have an issue? Truck has 102,000 miles on it. Thank you.
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Old 03-18-2019, 09:51 PM   #2
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Re: 67 sm420 question

Not sure if its normal but mine whined, I had it rebuilt but haven't driven it and it will be awhile before I do. I said it sounded like a school bus, at least you know your driving a real truck.
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Old 03-18-2019, 10:05 PM   #3
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Re: 67 sm420 question

I just used the very important search function and it sounds like it is a very normal thing with this trans. I think I might drain the new gear oil and put some Lucas in it. No banana peals though! See what the Lucas does I guess. Any more suggestions are greatly appreciated. Thanks.
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Old 03-18-2019, 10:13 PM   #4
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Re: 67 sm420 question

It is very normal for the 420/465 to have gear whine. If you pop the top plate off and look at those gears you will understand why. The Lucas may help but I wouldnt expect a miracle. These transmissions were loud when new and yours now has 50 years of wear on the gear teeth. Good luck and enjoy.
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Old 03-18-2019, 11:15 PM   #5
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Re: 67 sm420 question

If you have a T221 transfer case, it will whine. All straight cut gears in that t case.

I had a 465 / 205 in the '64 that I had. Don't recall any whining from that.

When I had the T221 in the '63 a few years ago, it also whined. Now with a 205, no whining.
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Old 03-21-2019, 12:40 PM   #6
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Re: 67 sm420 question

You probably have a 420/221 combo, which would be the last year of the old style noisy ones. As stated before, welcome to the world of "Real" trucks, this is normal. If this is not music to your ears like it is for some of us, products like DynaMat work very well
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Old 03-21-2019, 08:54 PM   #7
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Re: 67 sm420 question

Quote:
Originally Posted by '63GENIII View Post
If you have a T221 transfer case, it will whine. All straight cut gears in that t case.

I had a 465 / 205 in the '64 that I had. Don't recall any whining from that.

When I had the T221 in the '63 a few years ago, it also whined. Now with a 205, no whining.
Not straight cut on the high side but it goes through the idler gear so its louder than a 205 that is straight through.
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Old 03-22-2019, 06:17 PM   #8
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Re: 67 sm420 question

Here is a link to Novaks SM-420 page. Scroll down and check the note on the proper lubricant for a SM-420.

http://www.novak-adapt.com/knowledge...s/manual/sm420
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Old 03-23-2019, 12:43 AM   #9
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Re: 67 sm420 question

That is normal. It lets you know your oil level. If the thing is really loud your probally out of fluid. They will run dry for miles. Check your bearings and forks. If your missing the fork plastic/brass spacer that thing can ride against the gear making some noise. Other then that and bearings. The thing is as quiet as you can get it.
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Old 03-23-2019, 07:23 PM   #10
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Re: 67 sm420 question

A lot of good info guys. Thanks for all the replies! I don’t mind the whining at all but I just wanted to be sure it was supposed to sound like that.

Yes, welcome to the world of what a truck is supposed to be!! I’m a big fan and as long as I can afford the gas, this is going to be the daily this summer! Thanks again everyone.
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