Have a question about diffs. I have the DANA 60 (front) and 70 (rear) diffs. Not sure how to tell if I have limited slip or anything like that. I am going to change the fluids in them soon since I am approaching 45K. I tow a boat from time to time but havent towed much with the truck. I bought it used though so who knows. Just looking for recommendations on fluid. I have seen alot of posts about going to synthetic and so on. Also are the MAG-HYTEC covers worth $235. I dont think they look that great as good as the stockers but if there isnt a serious performance difference than why spend $500 on covers. I am also thinking about changing to 4:10's in the future. Any recommendations there. RIght now I am running 33's but will probably go to 35's before it is all over. With the 3:73 rear end I have seen a MPG dip. Just curious if 4:10 will help that or not. Im pretty sure it will help low end power and acceleration but not sure about mileage. Thanks
RT

 

Raise your rear axle, both tires off the ground. Take the truck out of gear and spin one tire either direction. If the opposite wheel spins in the opposite direction you do not have limited slip. BTW if you have 45,000 miles on the factory diff fluid, your limited slip (if you have it) is probably toast anyway. If you tow either heavy or often or both you should be running synthetic 75W-140 in the rear diff on a 2nd gen truck.

If your ONLY motiviation in switching to 4.10 gears is to improve fuel economy, you will probably die of old age before you put enough miles on the truck for the fuel savings to have paid for your gear swap.

Mag Hytecs? It's your money.

Good luck.

 

The Mag-hytecs rear diff cover is worth it (see below). Front is not. Don't worry about LSD you have 4x4.

If you want to know for sure, look at the codes on the sticker under the hood or on a piece of metal between two differential bolts. I'm not sure what the code is but the dealer can tell you.

 

For what it would cost to swap gears in front and rear diffs you could buy a lot of diesel or some mods to get back the power you lose to the big rubber