Limited slip friction modifier applications

[Dr_No]

Hey all, so I have a question regarding brands of limited slip.

My knowledge on limited slip additives is slim. Essentially our shop has been using Valvoline synthetic 75w90 in the majority of differentials that require 75w90 with limited slip. The gear oil claims to have limited slip additive, but we have had call backs complaining of chatter. Now there are lots of limited slip products available to us, however we have a large stock of AcDelco limited slip. Is it compatible with the mopar/ford differentials, or should I be bringing in a universal product?

 

[Jim Allen]

The manufacturer should be able to tell you for sure but I would strongly suspect so. It's usually pretty universal. I also found the need to add FM to the Valvoline in my LSD (Auburn HP cone type).

 

[andyd]

It may be apples and oranges, but changing to Mobil 1 75 -90 cured the clutch chatter in the Borman 6's diff. It is the only synthetic oil product I use.

 

[Clevy]

Redline is the only gear oil I will use.

 

[MetalSlug]

all fluid is alway better then what it drain out. Mobil 1 here too.

 

[Whitewolf]

Beware of using too much FM if you are adding it. FM of the right type and the right quantity can help or even cure your diff chatter but they are not all durable and what's more FMs are bad for oxidation performance, seal performance and a number of other issues. More is not better. I'm afraid that they are just a necessary evil. GM have a fluid that has FM built in and it's durable. If you like I can find a part number for it.

 

[Donald]

When I changed the gear oil in my Dodge Ram, I used the oz. listed on the Amsoil website of Mopar FM. It seemed the most straight forward way.

I could image that one container of FM could be more or less concentrated than another. But you will only see listed the oz of the OEM FM needed.

And if some gear oil has FM already mixed in, who says its in the proportion called for by the vehicle maker?

 

[Dr_No]

Thanks for the replies all. I did speak to the guys on redlines tech line, they mentioned when adding limited slip that I would probably only need a small amount. We're using CRC universal limited slip for those customers with "chatter". The reason we use the Valvoline gear lube is because they are our overall lube supplier. So at the moment, no way around the synpower gear oil.

 

[MolaKule]

I always recommend 1/4 tube at a time and then turning figures 8's in the parking lot.

I find most people overtreat the diffy with this stuff and then wonder why, at 10,000 miles down the road, their LS doesn't lock up or provide equal torque.

 

[Jim Allen]

There's nothing wrong with Synpower. Not the best you can buys but certainly not the worst.

I concur with Whitewolf and Mola, add as little as possible and in small amounts until symptoms disappear. Overtreating isn't good.

 

[Dr_No]

I agree there is nothing wrong with Synpower, just in certian applications our customers have returned with chatter. We won't be adding much to the call backs, so the differentials arent over treated. We go through usually 60L a week of the 75w90. Not often we have problems with it, but when we do the customers aren't pleased. Our old system was using the Petro Canada Traxon E 75w90 which contained no limited slip.. we carried a universal product and added it to the differential at time of service. Just that was phased out when we switched lubricant suppliers.