ranchertx

My anti spin clutch in the rear diff was making a clicking sound on turns, and, I drained and replaced the fluid and added a dose of anti-slip diff lube.
Now, several times when I have been loaded really heavy, when I go to turn, it feels like the rear diff is binding. (Almost like the clutches are not slipping on turns). It does not do it empty, just with a heavy load.

I initially thought the 4wd system was engaged, but, checked and it was in 2wd mode.

Just curious if anyone has experienced this? Think my rear differential is fixing to go out?

johnh

pull the cover and inspect!!!!!!!!!!!!!!

ranchertx

Will take it to a mechanic, dont know enough about rear differentials to know what to look for.

rebal

might just need a little more friction modifier.but I would open it up an see if theres anything that stands out,

ranchertx

I just can't figure out why with the truck empty it works fine, yet, when I put a ton or more on the truck it seems like the rear diff clutches are not slipping.

j-fox

Empty it may be slipping one tire on turns.

KATOOM

The reason differentials can chatter with heavy loads is because the lube is hot and thinner than when there's less pressure with no load. The hot thin oil will allow the clutches to grab more. But if you've recently changed the lube and everything looked fine then I'd simply add more friction modifier since not all lube brands and weights react the same to LS clutches but if you haven't changed the lube in awhile then as johnh suggested, pull the cover and make sure everything is OK.

totalloser

There is also another reason posis *tend* to chatter more when towing or loaded. The basic function of how the clutch packs engage.

Springs push the side gears against the clutch packs giving them "preload" but the majority of force that engages them comes from gear deflection from the spider gears pushing the side gears.

When you put a bigger load on the gears from hauling or towing, the extra load is moved by force that passes through these gears, and thus there is more deflection, which in turn puts more pressure on the clutch packs.

But if in doubt, it's pretty easy to pull the diff cover and have a look. If things are going badly it will be OBVIOUS, even to an untrained eye. You are basically looking for wear material, obvious broken parts, and metal shavings.

Your description isn't unlike what broken teeth on the spider gears might do. If that goes through the ring and pinion gears, you will need a whole rear end. If a tooth broke off a spider gear or something and *hasn't* gone through the r&p you might just need a posi rebuild, which isn't really that hard and doesn't require gear set up, which is where most the technical expertise and hassle lies in rear end work.