Gear oil choices for 3.92 LSD

[keanezheng]

Thanks guys for your input, let me reciprocate with a good deal. Amazon has the best price for the Mopar friction modifier. $7.15 per bottle. Seems legit with 1400+ reviews. Cheaper than Summit or eBay or any dealership for sure.

 

[1BADRAMLIMITED]

Thanks guys for your input, let me reciprocate with a good deal. Amazon has the best price for the Mopar friction modifier. $7.15 per bottle. Seems legit with 1400+ reviews. Cheaper than Summit or eBay or any dealership for sure.

thats where i got mine

 

[kdoublep]

That's where I got mine

 

[mtjag]

So, thinking about using the MOPAR 75w140 with MOPAR friction modifier in the rear axle since I have LS and the Valvoline 75w90 in the front axle. It would be my first change at 57000 miles and looking at the space for the front axle, getting a bottle positioned in there seems a bit dicy where as the Valvoline package is much more flexible. Any comments or suggestions?

 

[mtjag]

So, thinking about using the MOPAR 75w140 with MOPAR friction modifier in the rear axle since I have LS and the Valvoline 75w90 in the front axle. It would be my first change at 57000 miles and looking at the space for the front axle, getting a bottle positioned in there seems a bit dicy where as the Valvoline package is much more flexible. Any comments or suggestions?

by the way, we tow a 5800# travel trailer quite a bit, likely 50% of the time, and I have the 3.92 rear axle

 

[mtjag]

What's the downside if there is not enough MOPAR friction additive in the rear diff with limited slip. In other words, if I didn't get a full 5oz of the friction additive in the rear fluid, what will happen?

 

[TheWaterman83]

What's the downside if there is not enough MOPAR friction additive in the rear diff with limited slip. In other words, if I didn't get a full 5oz of the friction additive in the rear fluid, what will happen?

If you under-add or don't add any of the slip additive in a truck with an limited-slip rear, you'll get chatter going around turns and wheel chirping.

Trucks w/o limited slip rears (Rebel with e-locker) = Limited slip additive or not, doesn't matter.
Trucks w/ limited slip rears (non e-locker) = You must add limited slip additive, even if the gear oil has it in it already.

I used Amsoil Severe Gear oil in my front and rear diff, with no added limited slip additive as I have the e-locker.

 

[mtjag]

If you under-add or don't add any of the slip additive in a truck with an limited-slip rear, you'll get chatter going around turns and wheel chirping.

Trucks w/o limited slip rears (Rebel with e-locker) = Limited slip additive or not, doesn't matter.
Trucks w/ limited slip rears (non e-locker) = You must add limited slip additive, even if the gear oil has it in it already.

I used Amsoil Severe Gear oil in my front and rear diff, with no added limited slip additive as I have the e-locker.

Thanks for that. I used the MOPAR and added the MOPAR limited slip additive, I just don't know if I got enough in there. I measured out 5 oz but had to put it in one of the larger MOPAR bottles and then pumped it in. After I topped off, I noticed there was still maybe a couple of oz of mixed 75w140 and MOPAR additive in the first bottle I used. So, just second guessing now if I got enough in there. My dilemma is to drain out some and put more additive in, but that would also drain out some of the initial additive. I put in. I guess if it starts to chatter or chirp, I'll just do it all again.

 

[1BADRAMLIMITED]

If you under-add or don't add any of the slip additive in a truck with an limited-slip rear, you'll get chatter going around turns and wheel chirping.

Trucks w/o limited slip rears (Rebel with e-locker) = Limited slip additive or not, doesn't matter.
Trucks w/ limited slip rears (non e-locker) = You must add limited slip additive, even if the gear oil has it in it already.

I used Amsoil Severe Gear oil in my front and rear diff, with no added limited slip additive as I have the e-locker.

So I have a question.

I have a truck with axle lock button and down hill assist as well as 4hi lo and auto 4wd.

With that said if I activate the axle lock and then turn (left or right I get a chirping sound almost as if the side I’m turning to is pulling and not rolling. Is this normal?

I don’t get any error messages but I found it very odd and honestly scared me when I 1st used it

 

[kdoublep]

I'm pretty sure it's normal because your tires are spinning at different rates and theyre locked. I get something similar in 4 lo when turning. It's just not something I'm used to.

I use 4 auto often. 4 hi rarely, and never used 4 lo in practice.

I could be wrong on the noise.

 

[1BADRAMLIMITED]

I'm pretty sure it's normal because your tires are spinning at different rates and theyre locked. I get something similar in 4 lo when turning. It's just not something I'm used.

I use 4 auto often. 4 hi rarely, and never used 4 lo in practice.

I could be wrong on the noise.

That’s my thought. I once had a looooong time ago a 240sx and welded the diff in it and it did something similar just a lot more violent but I’m guessing same concept.

 

[CHeYeNNe71]

So I have a question.

I have a truck with axle lock button and down hill assist as well as 4hi lo and auto 4wd.

With that said if I activate the axle lock and then turn (left or right I get a chirping sound almost as if the side I’m turning to is pulling and not rolling. Is this normal?

I don’t get any error messages but I found it very odd and honestly scared me when I 1st used it

Only lock when on a slippery surface ie dirt, gravel, snow, etc. Dry pavement can cause damage.

 

[TheWaterman83]

So I have a question.

I have a truck with axle lock button and down hill assist as well as 4hi lo and auto 4wd.

With that said if I activate the axle lock and then turn (left or right I get a chirping sound almost as if the side I’m turning to is pulling and not rolling. Is this normal?

I don’t get any error messages but I found it very odd and honestly scared me when I 1st used it

100% normal. What was said about the e-locker on drive pavement is false. As long as you go in a straight line on dry/firm ground with the e-locker, it's not an issue. What you are experiencing is normal. The axle is locked and the inner or outer wheel, around turns, can't keep up/grip the same as the other wheel.

Now if you are making turns with the e-locker, yes, you should make sure you're not on firm/dry pavement. Same with 4x4. Although, you don't have control of the 4wd because it's auto.

I typically use my e-locker at boat ramps along with the 4x4 because I'm going straight, and I can't afford to slip. Many of the ramps I use to hunt are sand, dirt, or mud.