Engine/Transmission (1994 - 1998) Differential Oil

[Matt42]

It's time to change the differential oil in my 1996 4x4 5 speed. I checked the archives (!!), but still have some questions.



Does the hybrid Dana 80 really take 10. 1 pints? There is a discrepancy between the owners manual and the TSM. The TSM says 10. 1 pints for the Dana 80 in 4 wheel drive, and 6. 8 pints for 2 wheel drive. The owners manual just says 6. 8 pints.



I intend to use a synthetic or synthetic blend. Any comments about the relative quality of Mobil 1 gear lube over Valvoline synthetic? Does one tend to seep past seals? How about the Valvoline synthetic blend (which costs about half)? I have a bottle of Mopar LSD additive, just in case.



Most of my driving is stop and go in Phoenix, which has to be heavy duty by any definition.



Thanks.

 

[Missouri Mule]

Matt,

Good question, I don't know. I will have to look thru invoices to see how much gear lube was replaced. But I hink it is the lesser amount.



The better gear lube you use the less often you will have to change it.

I recently had amsoil 2000 put in so instead of doing once a year I will probably extend it to at least 3 to 4 years( mainly because of cost and I'm not in deep water usually- not yet any way).

 

[amsoilman]

MATT,

My "Check-Chart" Lubrication Guide indicates 10. 1 Pints for the dana 80 in a 4X4 applicaton, and 6. 8 pints for a 2X2 application for the '95-2001 model trucks.



It shows 6. 8 pints for the '94 Dana 80 model trucks on 4X4 application, and 6. 7 pints for the 2X2 application.





Wayne

amsoilman

 

[Pit Bull]

I've also been looking at this and it is 10. 1. Another thing to look for is that the oil is rated MT-1, whatever that is? Lets just say it is better for our dif's. I was looking at Royal Purple, but will have to have it shipped to me. So if i have to have something shipped I will go with the Amsoil 2000. This stuff seems to be used the most by the guys that use their trucks hard. I'm just undecided between the 75w90 and the 80w140 or whatever the small and large numbers are. Seems like the heavy weight stuff would give you more metal separation and less wear? But alot of guys think the light weight stuff is just as good or better if you don't tow alot. I know decisions, decisions?

 

[Matt42]

Yup. And when I tow, it's under miserably hot conditions.



I would think that the lower viscosity oil would do a better job of penetrating. What terrible things would befall a differential if it had 2 qts 75W-90 and the rest 80W-140?



OK. Who has Amsoil in the west side of the Phoenix area?

 

[Pit Bull]

Originally posted by Matt Shumaker

Yup. And when I tow, it's under miserably hot conditions.



I would think that the lower viscosity oil would do a better job of penetrating. What terrible things would befall a differential if it had 2 qts 75W-90 and the rest 80W-140?



OK. Who has Amsoil in the west side of the Phoenix area?

Matt I think the 80w140 flows about as well as the 75w90 and in Phoenix I am sure it would I think the 80w140 would just hurt your fuel mileage in the winter in Alaska

 

[TomGolden]

When I changed my rear diff cover from stock to the MagView cover, my rear diff now holds a shade over 6 quarts of fluid. I think it holds a bit over 4 quarts with the stock cover. Of course I have a 2001 truck, but I can't believe there would be much difference from the older trucks.



Tom

 

[Matt42]

Originally posted by Pit Bull





Matt I think the 80w140 flows about as well as the 75w90 and in Phoenix I am sure it would I think the 80w140 would just hurt your fuel mileage in the winter in Alaska

Well put! 80W-140 it will be. The problem I am finding is finding enough quarts of the same brand of the stuff in one place. The bubble pack parts stores sell the "I've never heard of" brands of dino oil, and have a bazillion quarts in at $1. 99 per. Then they have ONE quart of synthetic. Pooey.

 

[Pit Bull]

Just contact one of the Amsoil guys on the TDR they will ship you what you need.



I don't sell it and don't own any stock

 

[Matt42]

OK Phoenix area AmsOil Guys, where are you? When I go to an amsoil website (any website) I get directed to a factory store for ordering.

I don't want it next week. I need it this week.



Where are you?

 

[amsoilman]

I have three independent truckers using the 74W-90 gear lube in their trucks, and all of them swear by it! They all have indicated how the fluid runs cooler, one even said it was running 40 F lower!





Wayne

amsoilman

 

[Cooker]

Wayne,



What are they comparing the 75w90 to? OEM junk? Any idea how the oil analysis compares from the 75w90 to the 75w140?



Thanks,

Ryan

 

[Todd G]

My neighbor down the street is a Amsoil dealer. I'm sure he could set you up with the slippery stuff

 

[amsoilman]

Cooker,

I do not know what fluids they were using before they switched to the 75W-90, so I cannot tell you. As far as analysis is concerned, my 75W-90 was analyzed at 60,000 miles on the lube, and the Viscosity measured 15. 2 cSt@100 C. When new, the spec sheet shows 15. 7 cSt@100 C. !



All additives were within specs for new gear oil as well. I cannot comment on the 75W-140, as I only sold 1 case of it since ithe 75W-140 came out.



Best regards,





Wayne

amsoilman

 

[Cooker]

Thanks Wayne.



I take it that you recommend the 75w90 for most applications? I am supreised you do not sell more of the 75w140 to Cummins owners. Can you explain why this is? I would think the 140 is necessary for what most guys are using these trucks for and would hold up much better than the 90.



Thanks again,

Ryan

 

[JJW_ND]

75w90 Does Just Fine!

I have had great luck with the 75W90 for the last 218K miles in my 96 5sp. I hot-shotted the first 5 years pulling lots of weight and very long loads. Summer heat and winter cold. I found 50K to be a good time to change based on my use and the TAN getting up their. The rear diff is all factory original except for on rear wheel seal that failed at 18K prior to putting in Amsoil. Even the LSD is as tight as the day I picked it up.



Oil samples from most every change show very little wear just TAN getting high.



Not sure the 140 would help any more then the 90wt does already on the hot side. I'm sure it would be a little thick below zero. While synthetic helps allot for cold operation, their is NO comparison to a lighter weight oil for true cold weather operation, i. e. 5 wt oil in the motor.



jjw

ND