Synthetic 75W140 vs Conventional 85W140

[clintonhutson]

Hey guys...so I have been using a synthetic 75W140 in my rear differential (Dana 70) in my Cummins. Starting to seep some from the pinion seal. Due to work and other things currently going on, I don't have time to replace the seal. I was wondering if the heavier fluid will have any ill effects. Thinking that maybe since it is heavier and a conventional, that it will slow or even stop the leak. And if it does neither, then it is cheaper to keep adding until I get around to replacing the seal.

Thanks guys!

 

[SwampSurvivor]

Won't have any ill effects, but it also will not help the problem. One of my pinion seals leaks on the Cherokee and I (breifly) went to 85w140 gear oil - did not help the leak. Wasn't a big leak, either.

I just top it up with 80w90 every few months.

 

[Dufus2]

Check the vent, it may be building pressure or the lip-seal is just worn out.

 

[clintonhutson]

Originally Posted By: Miller88
Won't have any ill effects, but it also will not help the problem. One of my pinion seals leaks on the Cherokee and I (breifly) went to 85w140 gear oil - did not help the leak. Wasn't a big leak, either.

I just top it up with 80w90 every few months.


Kind of what I figured...like I said, I will try it for a little while. I'm not really expecting it to stop the leak...but as said, with no time to change the seal, it will at least be cheaper adding the 85W140 for a bit.

Thanks.

 

[clintonhutson]

Originally Posted By: Dufus2
Check the vent, it may be building pressure or the lip-seal is just worn out.


I checked the vent when I noticed it was leaking. It was plugged, but even after I cleaned it, the seal still leaks. Thinking the excess pressure might have helped the seal wear out prematurely. Oh well.

 

[dnewton3]

No fluid will cure a problem, but they can at times delay dealing with a problem until time/money present a better opportunity. The only way to know if it will work in your situation is to try it and see.