Trying to fix the rear end whine

[Dino]

I was looking at the car this weekend, trying to find something else to do to it and although there's a few things like replacing weather seals, it's the rear end that needs attention first.

Ever since I stuck this 741 pig with 2.96 gears in the axle has had a whine under load.  Starts around 25mph and stays with me until I let go of the gas, noise is under load only.

Although it may be as simple as resetting endplay I want to make sure all else is well so what should I do?  Should I replace the wheel bearings while I'm taking this stuff apart?  Do I need to remove the pig again?  (hope not)

I want to replace my drum brake cylinders with the bigger truck kinds so I'll do all that stuff at once.  I'd like to get the Tiken bearings but does anyone have a part number for those?

Once I find a way to stick a fourth gear in this car the axle gears will be replaced again but I have no idea when that's going to happen.  Transmissions are pricey!

[Chryco Psycho]

the whine under load only is the backlash in the gear set , if they have run like this for a long time even resetting the backlash will not stop the whine , there are no 2.7,2.9 or 3.2 gearsets available new only 3.5 up , you will have to pull the carrier out to reset or install new brgs .The axle brgs should be packed with grease but generally are in good condition , check for scoring or discoloraton

[elacruze]

the whine under load only is the backlash in the gear set , if they have run like this for a long time even resetting the backlash will not stop the whine , there are no 2.7,2.9 or 3.2 gearsets available new only 3.5 up , you will have to pull the carrier out to reset or install new brgs .The axle brgs should be packed with grease but generally are in good condition , check for scoring or discoloraton

+1

[c00nhunterjoe]

I wouldn't sink any money into a 741 unit. Get a 742 or 489 and build that instead.  As already stated, if the car has been run for a while with improper backlash the ring andpinion is already marked and resetting it won't get rid of the whine. Any way you look at it the center section has to come out

[Dino]

I guess I'll keep my hands off of this one and start looking for extra trans gears as I still have my perfectly good, and dead quiet, 3.55 gears. 

I've probably put close to 4K miles on the 2.96 gears so I'll take a guess and say the whine will not go away after resetting.  The axle bearings looked good when I took them out so all I did was remove most of the old grease and repacked them with the good stuff. 
I guess I'll just use this piggie until it has had enough torture.  Good thing I paid less than $50 for it.  It's a shame as I love these gears with a stock 727.

Thanks guys

[70 Charger RT]

Leave the old set in and crank the stereo.

[flyinlow]

They can whine for years, crank the radio and save your money for a good 742 or 489.   

[Hemidog]

I've never known a non-whining rearend in my 6 years of driving my Charger, must be nice....

[Dino]

Well the radio broke so this is going to be a problem.   

The right side channels don't work in my aftermarket radio after that major water leak last year and now for whatever reason I can't turn it off anymore so I took the front panel off but I need to get another radio, an amp, a subwoofer and mount speakers in the doors.  Until then it's whining time!

Hemidog, my 3.55 gears are dead quiet, at least I think they are because the engine was always in high rpm with that thing.

Is the 741 really that bad?  I have never had an issue with it except for the whine.  My 3.55's ar ein a 741 as well.  It's just a street car, I never race it.  Wasn't the 741, althoug the weakest of the three, still stronger than a Ford 9" and many GM axles?

[Cooter]

I guess I'll keep my hands off of this one and start looking for extra trans gears as I still have my perfectly good, and dead quiet, 3.55 gears.  

I'm afraid what your looking for doesn't exist, but lemme know if you find it. I've been looking for 30 years for Perfectly good, Dead Quiet Gears, in an 8 3/4 rear. Ain't seen 'em yet.

[flyinlow]

Is the 741 really that bad?  I have never had an issue with it except for the whine.  My 3.55's ar ein a 741 as well.  It's just a street car, I never race it.  Wasn't the 741, althoug the weakest of the three, still stronger than a Ford 9" and many GM axles?

I have used 741 carriers ,without problems.  Street tires and automatics limit the peak torque levels the unit is subject to. Dont do max acceleration or burnouts on rough pavement, which holds true for any axle.

[Nacho-RT74]

I'd like to eliminate the whine on mine 

I have known locally with valves grinder paste all over the gears, making to spin the pumpkin fast ( maybe with an air drill, or on a lathe... or maybe into the axle housing ), you can try to match the gears faces and then reset the backslash to make a quiter differential )

[BigBlackDodge]

The FSM says to remove the mother-in law from back seat.



BBD