Does it increase the friction, or decrease the friction in the differential clutches? I think if I had a little more friction in the clutches, that might help me solve a problem with my 40 year old Ford 4x4 truck equipped w/a Dana limited slip differential.
The problem is a “clunk” coming from the rear axel, almost certainly the diff slipping, when engaging “drive” or “reversed” from neutral. This truck has always done this and I just ignore as it doesn’t seem to cause any other problems. Other than being annoying. About 15 years ago I took a stab at solving it by replacing the diff clutches, but that provided only a minor improvement. I did add in the Ford recommended friction modifier. But I’m wondering if I could experiment by either putting in more, or less, or used something entirely different for the axel fluid and/or friction modifier, something recently invented. What do you think? And what does that friction modifier do, increase the friction, or decrease the friction?