Have a 1998 CTD 12V 4x4 with the Dana rear end (limited slip). Wanted to change the fluids, front and rear. Went to dealer to get the fluids, additive and gear oil. Additive was reasonable enought, about $9, but they wanted $40.96 per quart for the gear oil which was a synthetic.

Question is, do I have to use a synthetic? What fluid have you guys used? How many quarts rear, how many quarts front? Does it use a gasket or RVT?

Thanks

 

COASTAL brand 80-90W hypoid gear oil (Not Synthetic)
Posi-Trac Additive in rear
Fill front diff 1/2 to 3/4 below fill hole
Fill rear till it comes out of fill hole then cap off
Diff gaskets plus Mega Black RTV
This is how I Roll
Brandon

 

Dealer was trying to get in your pocket. I recently priced diff. oils at the local Chrysler dealer. 75-140 synthetic was about $25 /Qt., 75-90 quite a bit less. I bought Royal Purple for $12.95 /Qt. at the local CarQuest store.
Dodge has specified synthetics on newer trucks because of higher heat tolerances. Non-synthetic oils seem to work fine on older trucks, at a much lower cost.

Dan

 

How about 140 vs 90? I was going to swap some out and I got stuck at this choice. What are the pros and cons?

-Dustin-

 

140 is too thick IMO in winter it would be like a bowl of molasses in the pig 90W is golden!
Brandon