Redline Synthetic Gear Oil for the Diff

[smiley1]

I just ordered some. I got the 75-90 for the front and 75-140 for the rear. I also got some of thier LS additive just in case.

I had the front and rear diffs rebuilt a couple years ago and am not sure if the dealer put in the right stuff. I dont get as good of MPG as before. We will see if we have any changes.

I will probably put synthetic transmission oil in the T-case later, but Im not anticipating any change there.

I did a lot of searching on bobistheoilguy.com and found that the redline gear lubes are close to the best out there. AND it was cheaper than Mobil-1 synthetic.

The 75-140 is back ordered so it will be Feb before I can get it in.

 

[smiley1]

I got my redline the other day. I removed the old diff fluid from the front. It was black as night. Smells yummy too. I installed the 75-90 in the front diff and took it for a test drive. It runs fine. Just a bit quieter. the 75-140 was on back order so I wont get that in until later. Ill keep you all posted. Im looking for better MPG.

Anyone else try Redline?

 

[Premier]

I use Royal Purple in mine

 

[glfredrick]

i'm currently running Mystic (who makes that?) which works great - and it was hardly more expensive than regular gear oil at Farm and Fleet in Wisconsin.

 

[aldive]

I, on the other hand, am fond of Amsoil.

 

[smiley1]

I, on the other hand, am fond of Amsoil.

IIRC I saw one of your posts over there...or maybe that was on the sct forum...

Anyway, RP, RL and Amsoil were all highly recommended. I almost went with Amsoil but a couple folks there said they had borderline OA results with others relating that it was overpriced for what it was. While taking everything with a grain of salt, I subsequently chose RL as I saw zero negative feedback.

Is Mystic synthetic?

 

[glfredrick]

If I had my druthers, I'd also take the Amsoil. Don't be swayed by supposed independent oil tests - someone is paying for them - and that someone generally discovers for their own products... Funny how that works... I've had perfect results with Amsoil for decades - it is rather a known and satisfying oil for me.

I picked up the Mystik (proper spelling) because it was cheap - and yes, it is full synthetic.

Since my last post, I dug up some info on the Mystik - and it turns out that they are a division of Citco and long on the field as a known performing oil.

Here is a nice evaluation of a number of different motor oils (not for the axle formulas, but still worth reading).

http://www.micapeak.com/info/oiled.html

Here is the PDF spec sheet on the Mystik gear oil line...

http://www.docs.citgo.com/msds_pi/591236.pdf

http://www.citgo.com/Products/LubesOils/Mystik/MystikGearOils.jsp

 

[aldive]

I almost went with Amsoil but a couple folks there said they had borderline OA results

with others relating that it was overpriced for what it was.

I have had nothing but great OA results using Amsoil with extended OCI.

Isn't everything thatis truly good expensive? And if you do extended OCI, it cost no more than other oils.

 

[smiley1]

I have had nothing but great OA results using Amsoil with extended OCI.

Isn't everything thatis truly good expensive? And if you do extended OCI, it cost no more than other oils.

No no no... I was talking about the DIFF fluid. I was not trying to say that it was inferior, just that it was the only product that I could find with only a TRACE amout of bad feedback and even then they said it was good, just overpriced (Again, talking about the diff fluid).

Don't be swayed by supposed independent oil tests - someone is paying for them - and that someone generally discovers for their own products... Funny how that works... I've had perfect results with Amsoil for decades - it is rather a known and satisfying oil for me.

These are regular folks that post thier OA's (For diffs) on the forum. I think Amsiol is a great product as well as Redline. The deciding factor was just the absence of any negative feedback on the Redline which ultimately led to my final dicision.

Thanks for the links glfredrick.

 

[Afboy143]

Any write ups on how to change it all and where they are located? I know where the rear is located but where is the front? Any precautions before I try this? My truck is nearing 100k so I am doing my best to keep my baby going

 

[svande8952]

Why use different weights front and rear? I could see if you rarely used the front, but if it's AWD the front will be engageing more than a standard front. What is the reasoning?

 

[smiley1]

Why use different weights front and rear? I could see if you rarely used the front, but if it's AWD the front will be engageing more than a standard front. What is the reasoning?

On the 98 (other years are included) have different weights for front and rear. I contacted Amsoil and they even said not to use the same weight for both but to revert to fords recommendations as there is a possibility of foaming.

 

[svande8952]

oh, ok Thanks. I would never have thought to use 2 different oils.

 

[97BlackX5.0]

i couldnt find 75w 140 synth around me so i put in 80-90 synthetic in the rear with the friction modifier... never had a problem wiht it

 

[smiley1]

I had a problem with Summit. Their product description was flawed and I ended up with some lightweigt oil instead of the 75-140.

Since I ordered extra 75-90 I called redline and spoke to a tech about using the 75-90 in the rear. He said he recommended the 75-140 as ford recommends but said the 75-90 would work very well and give me better economy. A search on Bobistheoilguy.com showed that some folks running the 75-140 were having bearing failures where folks using 75-90 were not. Ford used to use the 75-90 (or 80-90) in its rear 8.8 LS applications.

Summit refunded me the price for the bottles of light weight oil and said I could just keep the bottles.

I will be doing a mpg test soon. So far everything works well.