EP additive?

CCI

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249
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New Mexico USA
Thread starter
1991 FJ 80, open diffs front, center, and rear, only the center is a locker. Got a serious whine under any amount of throttle and a bit of clunking at shift points. Is there an EP additive for the differentials that will help subdue the gear whine?
 
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4,006
Location
Chicago, IL
in my opinion, an EP additive reduces wear and will not reduce the noise. perhaps a thicker oil will, but the whine is likely caused by pattern wear on the teeth and/or the bearings. Clunking at shift points indicates too much lash somewhere. it could be in the bearing preload, the gear spacing; could be made worse by worn splines, u-joints; lash in the entire driveline
 
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MolaKule

Staff member
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Iowegia - USA
Originally Posted by CCI
1991 FJ 80, open diffs front, center, and rear, only the center is a locker. Got a serious whine under any amount of throttle and a bit of clunking at shift points. Is there an EP additive for the differentials that will help subdue the gear whine?
No there is no such additive. As Tomcat stated, you already have something worn in the differential or elsewhere in the drive line.
 
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4,084
Location
Texas
Back in the day , I heard of STP being added to manual transmission and differential lube . Do not know how well that works ?
 

CT8

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15,409
Location
Idaho
Full time FWD? The locking of the transfer case locks differential between the axles, Probably a good shop needs to look at the problem.
 
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