I am going to change fluids tomorrow. Hopefully, you all can save me repeated trips to the store. Is this info right? Front differential - 80w-90 - 7pts
rear differential - 80w-90 - 7pts
transfer case - Dexron III - 6 pts
getrag - 5w-30 - 7 pts
Any suggestions? Thanks for the input.

 

the tcase is a np205 gear driven. use gear oil in it. duno howmuch, usually fill up and check with finger through hole.

jiMMy

 

Forgive my ignorance, but in a gear case, as long as you have a magnet to remove abrasive particles, id there any need to change the oil? Oils just get contaminated in IC engines but they don't wear out in gearboxes.

Edwin

 

there is still wear on it and the il will break down eventually, especially if the PO used the truck hard weather towing or pulling. just added piece of mind for a new owner knowing the service records. granted the tcase and trany are more like 30,000 miles + for changing. but up to you either way!

jiMMy

 

Front axle should be 6.5 pints. The diffs should only be filled to 3/8 inch below the hole. Extra gear lube in the rear often ends up on the brake shoes.

Xfer is 4.5 pints of 90 weight, 80W-90 will be fine.

4.5 quarts in the trans, that is overfilling by 1 qt to keep the input bearing lubed. I did this by putting a street elbow in the fill plug hole, I don't know if there's room on a 4X4 to do it that way. Others have used one of the upper PTO cover bolt holes, you can also pull the shifter to do it. I like Redline MTL in the Gutbag, but Mobil 1 5W-30 is used by a lot of people.

 

Edwin, conventional oils get sheared down (lose viscosity due to the gear action) and also oxidize over time. On a truck that does a lot of towing, the rear end can run as hot as 300 degrees which speeds up the oxidization. They need to be drained periodically, although I'd only use the 15k schedule on a truck that did a lot of towing. Like Jimmy said, 30k is soon enough. Synthetics are generally better, but they have the same problems eventually. On a manual transmission there's a lot of brass in the oil from the synchros that you need to dump, obviously a magnet is no help there.