Was time to change the fluid in my rear diff so I ordered a Mag Hytek cover and some limted slip additive. Directions say 12 pints but I only got 9 pints in with 2, 4oz additive bottles and I'm almost to the max line on the dip stick. Drove it for one mile to check the fluid level and it didn't change. Is this like the auto where you never really get all the fluid out? Truck is parked in the garage. When adding the fluid I had the oil level indicator plug out and it started flowing when I didn't even have the entire 8th pint in.Twogun

 

I replaced my Dana 70 OEM cover with a Mag Hytec last August. I let the differential housing drain over night. After I installed the cover, I put in 4 quarts and 14 ozs. of synthetic gear lube. Before that, I put in 6 ozs. of Mopar limited slip fluid. I re-checked the fluid several times and ended up with the level being slightly above the half way mark on the dip stick. So far my anti-spin differential seems to be working properly. I believe that Mag-Hytec's recommendation was 4 ozs. of LS fluid per 3 quarts of gear lube. This equates to about 4.1667% - that's how I ended up with 6 ozs. of LS fluid. I might add that since my truck doesn't tow or drag race much, I didn't feel a need to fill the fluid level to the top of the dip stick.

 

if you replace with synthetic gear lube you dont have to add limited slip fluid since synthetic has enough viscosity. If it does start to shudder around corners then add 1-2oz and go from there.

 

Some gear lube comes with it already in. Then one doesn't have to add or add much. What I buy doesn't so I putin what it says to and add one or two bottles more and have never had a problem with the clutches. I think that gravel corners are where you will find if you clutches are working properly or locking and unlocking properly? If you put some modifier in did you do a bunch of figure 8's to mix it up?

 

That's not necessarily true. If you do a search on this forum or the TDR forum you will find that just because you put in top of the line synthetic gear lubes doesn't mean that you don't have to add friction modifier. I guess that it depends on how loose the clutch packs are set up in the differential. I've been dealing with my truck for almost 6 years and I've experimented with several brands of synthetic gear lubes and each case, I've had to add friction modifier, usually 3-4 ozs. when the truck had the OEM differential cover. With the Mag-Hytec cover, you have to put in more fluid and possibly more friction modifier. Yes, it's better to put the gear lube in, then drive the truck for a few days and see how it goes. If you get shudder/chatter etc., then add the friction modifer 1 or 2 ozs at a time until you get the desired limited slip effect. I did mine all at once with the Mag-Hytec because I know from past experience how much friction modifier my trucks' differential needs using the same brand of gear lube.

 

Have added five quarts to this point plus two 4oz bottles of limited slip additive and is just below the max level on the dipstick. As for synthetic not needing additive I have run Amsoil before and got some major chatter so this time I put Mobile One in and added it right away. No problem so far. Twogun