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rear axle gear noise , what to do , If anything

gtx6970

gtx6970

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Ok, My 383 car has a 741 case rear axle. sure grip with 3.91s of unknown manufacturer.

At low speeds , say below 30 mph or so . I get hardly any noise from the rear. And maybe just a touch of gear noise on hiway speeds. I can live with that.

Problem is at approx 35 to 40 mph range and real light throttle it gets loud, actually annoying. Its worst if just enough throttle to keep it in that speed range. Let off or get into it harder just slightly in either case and the noise fades away BY A LOT

Anyone in southern AZ have a good 3.23 they want to work a trade
 
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Gear noise? or Bearing noise? Bearing noise gets worse with time and mileage. Not sure about gear noise...
 
Definitely not a bearing noise .

Like gears are set up wrong ,,,Or Ive heard some gears are just noisy no matter the setup.
 
Well, if it's gear whine from being set up wrong, you know what has to happen.... :poke:
 
Cut to the chase, turn up the stereo, tun off the hearing aids, ear plugs or new gears.
 
Bill...In that file folder I gave you when you picked up the car, should be the receipt for the Sure Grip install and rear end re-build. I am not sure if I got it from West Coast Differentials or Randy's Ring and Pinion. The original set up for that Peg Leg was 2:76's and the ring and pinion were sourced from either the 2 I just mentioned. It was done by this firm...https://www.jimdandytransmission.com/...and they have a great Mopar Reputation. At least that was what I got from all the inquires I made locally and then on MOPARTS.com. I no longer use MOPARTS.com so as to if they are still up, I do not know as I left them a long time ago. I rebuilt the entire rear end after I disassembled it with a thorough cleaning and painting. I installed new Green Bearings...I know they are not the original MOPAR type Tapered Bearings...and had the axels checked for straightness and condition. They cam back as fine and usable. The Bearing Races were replaced with MOPAR new ones in the axle sleeves both sides. I used the correct MOPAR Rear End Lube and checked for any leaks and the correct amount of it after I re-assembled it. The valve at the center section was a new correct MOPAR one. I then adjusted the pre-load according to the FSM and got it all back and into the car. As for the noise? I would go so far as to say it might just be the Green Bearings as they have a reputation of not holding up and in fact failing in a rather short time. I was on a budget for a lot of the work I did and I probably went for the ease on my wallet as opposed to forking up for the better Tapered ones. That's about it for my input have been the owner before you. If you need any more input or have questions, you know that you can always either call or PM me/email if you need to. Just good MOPAR friend relationships and my integrity is also just as important...cr8crshr/Bill:thumbsup:
 
There isn't a great selection of new gears for a 741. 3.55s or 3.73s only, I believe. I'd move to the 3.55s. Buy the best quality you can find. Oem Mopar gears from a dealer if you can find em.
 
If it is gear noise, you won't be able to quite it down. New ring and pinion is the only solution.
 
cr8crshr said:
As for the noise? I would go so far as to say it might just be the Green Bearings as they have a reputation of not holding up and in fact failing in a rather short time....cr8crshr/Bill:thumbsup:
Click to expand...
You better not have cursed me with that comment, as mine are going on 20+ years now!
I have to wonder if because the car is now being driven more now than when cr8crshr had it that it may just need some adjustment and nothing more? I'm just spit ballin here. Good Luck
 
cr8crshr said:
Bill...In that file folder I gave you when you picked up the car, should be the receipt for the Sure Grip install and rear end re-build. I am not sure if I got it from West Coast Differentials or Randy's Ring and Pinion. The original set up for that Peg Leg was 2:76's and the ring and pinion were sourced from either the 2 I just mentioned. It was done by this firm...https://www.jimdandytransmission.com/...and they have a great Mopar Reputation. At least that was what I got from all the inquires I made locally and then on MOPARTS.com. I no longer use MOPARTS.com so as to if they are still up, I do not know as I left them a long time ago. I rebuilt the entire rear end after I disassembled it with a thorough cleaning and painting. I installed new Green Bearings...I know they are not the original MOPAR type Tapered Bearings...and had the axels checked for straightness and condition. They cam back as fine and usable. The Bearing Races were replaced with MOPAR new ones in the axle sleeves both sides. I used the correct MOPAR Rear End Lube and checked for any leaks and the correct amount of it after I re-assembled it. The valve at the center section was a new correct MOPAR one. I then adjusted the pre-load according to the FSM and got it all back and into the car. As for the noise? I would go so far as to say it might just be the Green Bearings as they have a reputation of not holding up and in fact failing in a rather short time. I was on a budget for a lot of the work I did and I probably went for the ease on my wallet as opposed to forking up for the better Tapered ones. That's about it for my input have been the owner before you. If you need any more input or have questions, you know that you can always either call or PM me/email if you need to. Just good MOPAR friend relationships and my integrity is also just as important...cr8crshr/Bill:thumbsup:
Click to expand...
Bill, Absolutely no worries brother.

The 3.91s are a blast around town. Just not hiway friendly. And I like road trips in my cars. At 70 mph or better the 383 is buzzing pretty good

If I can come up with some 3.23s without spending a small fortune I may go that route
 
Sounds like the noise in the 489/3.55 rear I set up except the steady rpm howl occurs between 45 and 50 mph. I doubt you will be able to have much done with it. Another set may be even worse.
 
Richmond Whine possibly? it's a lovely sound, had it in 3.55's in a 741 case and currently in 3.91's in a 742 case.
 
AR67GTX said:
Sounds like the noise in the 489/3.55 rear I set up except the steady rpm howl occurs between 45 and 50 mph. I doubt you will be able to have much done with it. Another set may be even worse.
Click to expand...
BearDodge67 said:
Richmond Whine possibly? it's a lovely sound, had it in 3.55's in a 741 case and currently in 3.91's in a 742 case.
Click to expand...
I had friend, since passed away, who owned his own rearend shop. He was complaining about gear quality fifteen years ago. He said there were certain brands he could never get completely quiet.
The ones he set up for me were always quiet, but I don't know the brands. He even did some 5.14s that were quiet, in a nine inch.
 
I've heard banana peels can quiet noisy gears. Just long enough for a quick sale!
Mike
 
69a100 said:
You better not have cursed me with that comment, as mine are going on 20+ years now!
I have to wonder if because the car is now being driven more now than when cr8crshr had it that it may just need some adjustment and nothing more? I'm just spit ballin here. Good Luck
Click to expand...
Maybe the pinion nut came loose or the pinion bearings are loose/worn. Kim
 
“Problem is at approx 35 to 40 mph range and real light throttle it gets loud, actually annoying. Its worst if just enough throttle to keep it in that speed range. Let off or get into it harder just slightly in either case and the noise fades away BY A LOT”

This is exactly the description of the noise in my 489, except mine sets in 40 to 45, give or take a little. I‘m not expert or even experienced but I did probably 15 or 16 set ups with pinion depth and backlash changes and checking patterns using a crush-sleeve eliminator. I managed to eliminate the coast whine by concentrating on the coast pattern which shaped up over a narrow range of pinion depth changes. The drive pattern shaped up over a wider range of pinion depth and it could be what worked best on the coast side was not optimum on the drive side. I did manage to reduce the drive side noise a little but it still gets that light throttle howl especially on a slight grade rise. Or it could be just the gear harmonics phenomena you hear some guys mention.
 
gtx6970 said:
Bill, Absolutely no worries brother.

The 3.91s are a blast around town. Just not hiway friendly. And I like road trips in my cars. At 70 mph or better the 383 is buzzing pretty good

If I can come up with some 3.23s without spending a small fortune I may go that route
Click to expand...
Those 3:55's I included should help as they are supposed to be OEM MOPAR. Just that I never really looked for any stamping to confirm that. I agree on 3:23's as they are great for just cruising and 3:55's also but with a little more punch around town. As the car came with originally with a 741 case, I would have much rather preferred to find a 742 case as they are the more popular...cr8crshr/Bill:thumbsup::thumbsup::thumbsup::usflag::usflag::usflag:
 
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