Royal Purple Max-Gear - Issues

[RC]

I just switched to Royal Purple Max-Gear 75w90 on the rear end of my Dodge 2500. The truck has a limited slip differential and I was told the RP already had a friction modifier in it so I should be all set. Wrong.

After a few hundred miles the LSD started to chatter around corners. I spoke with a Royal Purple tech and was told to add some additional Mopar friction modifier 1/2 a bottle to start and then the full bottle if I was not happy with the results after adding 1/2.

The first 1/2 of the bottle helped but not much. After adding the rest of the bottle the chatter was gone from the LSD and the function does not appear to be comprimised due to the addition of extra friction modifier.

I am just curious if anyone has had similar experiences with the Royal Purple gear lubes?

 

[Rebel Rouser]

I currently have Royal Purple 85W-140 Max-Gear in my Dodge's Dana 80 limited slip rear axle and did not have to add any external friction modifier. It works fine with no chatter.

From what I've observed, it seems the lighter weight synthetic lubes require additional friction modifier in LSD's, whereas the heavier xxW-140's do not. Also, no two clutch packs(on Dodge trucks anyway)appear to be the same performance wise. Some have had to add quite a bit of friction modifier to stop chatter.

 

[Grossomotto]

I've used Royal Purple GearMax with no problems on newer Toyotas. RedLine is just as good, if not better. They offer a complete line of products. Check out their 80W140 Gear Oil which is recommended for heavily-loaded and low-speed differentials, including limited-slip, and where reduction of limited-slip chatter or gear noise is required.

Redline Products

"

 

[sbc350gearhead]

I have RP 75w90 maxgear in two diffs with eaton posi's, and neither one makes any noise.

 

[outrun]

Side note,

I had this concern of not using a LSD Additive on my GM differential even though the Redline bottle said it was not necessary.

The dealer further reassured me that Redline is right by saying your car is GL5 and Redline is GL5/GL6 rated.

Well, so far no chatter what-so-ever.

Are you sure the mechanic actually used your Royal Purple oil??

 

[RC]

I installed the gear oil so I am certain that it is in there

It appears that I am the only one to experience any issues with the Royal Purple. Overall I am impressed by RP's products but I must say I was a bit disappointed by this situation.

Thanks for the replies.

 

[rugerman1]

I changed the gear lube in my '98 Dodge Ram 2500 4X4 this spring.I called the local dealer and asked about the Mopar posi additive that they have.He said that EVERY Heavy Duty Ram they ever seviced needed 2 bottles of posi additive to ensure no chatter.
I put both bottles in when I switched to the best gear lube Pennzoil sells.Never had a problem with any chattering.
I have no idea if I needed both,I just know enough to trust the factory mechanics that work on these vehicles every day.

Mark

 

[LS1-CAMARO]

I switched my rear to RP at 15,000 miles in my 2001 Z28. Now at 50,000 miles with no issues.

 

[RC]

Update: One bottle of LSD additive solved my problems. Thanks for the replies.

 

[Ken2]

quote:

---

Originally posted by outrun:
Side note,

I had this concern of not using a LSD Additive on my GM differential even though the Redline bottle said it was not necessary.

The dealer further reassured me that Redline is right by saying your car is GL5 and Redline is GL5/GL6 rated.

Well, so far no chatter what-so-ever.

Are you sure the mechanic actually used your Royal Purple oil??

---

GL-5 does not relate to friction modifier for limited slip--a gear oil can be GL-5 with no limited slip additive. It seems that most GL-5 gear oils for differentials already have some limited slip additive in them, and many folks report that they need to add more. GL-6 is an obsolete spec.


Ken