Changing Rear-end fluid-Sythetic/limtied slip issues

[DanaLittle]

Changing Rear-end fluid-Sythetic/limtied slip issues



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So I changed out the fluid in the rear and refilled with Amsoil severe gear

75-90 and 2 bottles of friction modifier for the limited slip and took truck on drive and the rearend fills like it's grabbing when turning corners.

I went into school parking lot and turned a bunch of figure 8's to work the lube onto clutches and it is still grabbing. I've put 150 + mile on it since changing fluid. Is there something I'm missing or is the rearend wore out ? Everything was fine before changing fluid. The rearend made no noise and it wasn't grabbing.



Any suggestions ?



I dont want to hurt anything by driving it like this. I even took off the rear driveline and drove around to make sure it wasn't the u-joints. the noise was still there but not so bad. I looked at the u-joints and they feel ok.

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[cerberusiam]

Amsoil is known to do that on some units. No matter what it never works like it did before. Change back to something like Valvoline 75-140 Synthetic and the friction modifier and the problem goes away. Just the nature of how the fluid is reacting with the clutches.



Will it tear anything up? Probably not if its not sliding the tire. You may see accelerated wear on the clutches but even that is debatable due to what the fluid and modifier is doing.

 

[SAndreasen]

i just changed my rear end fluid , i use ether to clean out the housing real good which also dries the clutches out which causes the clutches to chatter i added a bottle of CRC limited slip additive and the clutches quit chattering on turns and on take off

 

[Bob Beauchaine]

My tests and oil analysis show that unless you do a lot of heavy towing 75W140, it retains too much water. It just does not get hot enough to boil off the natural occuring water build up in daily driving.



I've run Amsoil 75W90 in my rear diff for over 200,000 miles and it has been trouble free - again using oil analysis and performance as a guide. I change the rear diff fluid every 18,000 miles and add 2 bottles of friction modifier. Just adding friction moifier is not the recommended procedure. You should add 1 ounce then test and repeat until the chatter goes away.



As noted on DTR web site wait for the Monday feed back from Amsoil.



Bob

 

[Wiredawg]

I believe your problem is you used friction modifier; synthetic diff fluids don't require friction modifier for limited slip.



Wiredawg

 

[DanaLittle]

Called amsoil they said to drain and refill with out the additive. So I did still making noise. So I added a little bit of additive at a time till i used a whole tube and a little more. Still making noise. I put 100 + miles on the oil change still no good. So I thought that I would change it 1 more time and go with Regular gear oil and see what happens. I've got about 15 miles on new gear oil and some additive. I did 12-15 figure 8's in school parking lot and it still making some noise. Sounds a little better.



Does anyone have a good source for the clutches in the rearend ?



I have the D70 out of my wrecked 93 I could put in new truck. Just not sure what is faster. Removing the whole rear out of 2 trucks to swap or just pull the center and replace the clutches ?

 

[jeepit]

Straight Amsoil in mine... ... .