Engine/Transmission (1998.5 - 2002) Dana 80 fluid

[Paulsdodge]

Okay Guys I need your help,

I want to change the rear differential fluid in my truck. It has the H. O. motor with the six speed transmission. Therefore, my truck is supposed to have the Dana 80 rear axle. My truck also has the limited slip axle, so I know I am going to have to add some friction modifier. My question is what type of fluid should I use? The dealer says the fluid that goes into this truck is 16. 00 bucks a quart, OUCH!! Surely there is something else that is more reasonably priced that I can use. I tow with my truck very little, and normally only drive it back and forth to work. When I do tow with my truck it would only be 4,000 lb or less plus the weight of the trailer twice or three times a year. Also how do you know when you have enough friction modifier ?

 

[TPilaske]

I use Royal Purple 85W-140 in both diffs. It has friction modifier already in it. I like it. I also tow alot. There's a bunch of choices out there. Do a search here or research on the 'net for gear oil. www.oiltown.com has good prices on RP. Good Luck! Hope this helps!



Tony



PS -- They only recommend dumping the factory oil if your towing alot. You say you only tow about 3 times a year. I probably wouldn't even change it. If you want the added comfort of knowing you have a nice synthetic in your rear, change it!

 

[thejeepdude]

I just changed mine out for Redline GL-5/6... it's about $7. 50/qt and doesn't require a friction modifier either.



Josh

 

[HVAC]

Find yourself some 75/90 gear lube at the parts store. It's as cheap as $3. 00 per quart.



Friction modifyer is to keep the clutches from popping. If you hear a noise like a broken axle or loose lugnuts or a bad U-joint in the rear, then you need more friction modifyer.

 

[RustyJC]

We tow a 13,500 lb 5th wheel, so I changed the Dana 80 fluid to Royal Purple 85W-140 synthetic. No additional friction modifier is required - it's already in the Royal Purple formulation. Works great!



Rusty

 

[dresslered]

I'm a big fan of LE607 as recommended by Roy at Mag-Hytec. I only added one bottle of friction modifier. Then go out in a large parking lot and do a series of figure eights (you'll get some strange looks) to work in the modifier. If you still get a little popping in the rear, you can then add a little more.

 

[rkressg]

I use Valvoline 80w90 gear oil that I buy from NAPA. I also use one bottle of Mopar Limited Slip Friction Modifier. It is cheap, but I change it every 15,000 miles. I do heavy towing with my truck, it has 60,000 miles on it and I have had no problems with it.

 

[JJW_ND]

phumerick:



Any name brand (Redline, Mobil, Amsoil, Valvoline, ... ) that is GL5 and MT1 rated will be better then what Mopar will provide and much cheaper.



If you tow heavy and often AND in HOT temps, I might consider the 85W140. I have ran the 75W90 for the last 220K miles towing very heavy and on very hot days with excellent results.



As far as the additive goes, only use Mopar LSD additive. If the oil you use has LSD additive in it, do NOT add any Mopar until you drive it a while (several figure 8, sharp turns helps). If the oil does not say whether it has ir or not, add about 1/2 of the small Mopar bottle and try it a while. You will get a popping noise if you need more addidtive. You may evey need 2 bottles. I have had to add two bottles to My Dana 80 and I use Amsoil which has the additive.





Edit... . Also, almost any of the Permatex silicone gastket stuff will work (High temp Orange, Blue, Black). I have used than all and none have leaked. There is no gasket. Clean cover with brake clean, add gasket stuff, bolt up, wait maybe an hour (maybe five minutes if in a rush), and add oil. Fill to it runs out the plug hole.





jjw

ND