Differential oil

[kwb]

Don't waste your time or money on Walmart, tractor supply or any other cheapo oil. Most of them are low pressure oil and have very little protection for the Synchronizers. 20% of my Diff noise is gone using a quality high pressure oil that works in the Diff and the Trans.

[raymond]

What oil are you using

[Mark]

I use Lucas oil

[kwb]

I just switched to Lucas 80w90 about a week ago. I was using tractor supply 90w mineral oil. Bad choice. I have about four hundred miles on the 151 with a nos transmission and a nos rear diff. rickf told me the loud diff for the most part is normal and I think he knows what he's talking about. I did get the diff singing quieted some by setting the preload a little tighter and back lash at .020 . Very happy now

[rickf]

I posted last night but I guess I hit the wrong button since it did not go through but I am curious as to how you tell what the difference is between a low pressure oil and a high pressure oil? Personally I use Valvoline 85W-140 Due to the high heat generated in these units.

[Dumbdog]

So new to m151a2 ownership
Bought a ford 151a2 out of estate ….in checking all fluids ,both diff have grease in them ,seams crazy
Was this a old school mindset to quite the diffs or what ?
Just checking before I tear them down
And views on this would be helpful
Thanks

[rickf]

Welcome to the forum. I have a couple theories on why there would be grease in them. One was exactly what you said, to quiet them down and the other would be to stop leaks. The seals on these are fairly problematic and they are not a lot of fun to change. Either way I can pretty much guarantee that if it was driven on the road with grease in there, even if it is corn head lube, there will be some damage since grease is not made for that type of use. It could be that the vehicle was just used around the farm and the farmer used corn head grease in there which liquifies in use and firms up as it cools. This stops most leaks. And only driving around a farm it would work just fine. Getting it all out of there and cleaned out is going to be a chore. Plan on replacing all the seals which do all come in a kit. The kit will also have sleeves for the yokes, you do have to use the sleeves since the seals are sized for the sleeves. Be sure the yokes fit tight on the splines and do not wobble sideways. If they do you will need to get new yokes.

[kwb]

Hi rickf
The Valvoline product page lists extreme pressure oil that I haven't seen on the bargain oil products. I'm not an oil chemist so I rely on oil company information.

[Dumbdog]

Thanks
That’s what I thought also
Was a parade car from what I gather and sat ten years in a garage with no oil drips underneath ,
I knew something was amiss
Why I checked right away when I got her home ….
Would you have a good reference/recommendation for parts ?
Thanks in advance

[Sledge303]

This is what I used in the rear differential when it was replaced.
The unit I removed needed rebuild, something i don't have the time or tools to do, and buying a new unit was cheaper than paying any shop I could find locally to open up a differential.
This lube choice was recommended by someone experienced who I trust.
It is also used in the transmission (after replacing the output and 4X4 selector shaft seals)
I am surprised how much quieter the transmission is now.

[Dumbdog]

Where did you buy diff ?
Also for some reason I’m not authorized to view photos ?
So I can’t see it

[rickf]

I just checked the permissions and all is in order, wait until after you get 10 posts and you are off the probationary period and if you still have issues let me know.

[Dumbdog]

Thank you

[Mark]

I understand that synthetic oil is filtered more than regular oil.It is still oil.The engine/differentials will leak more thru the old gaskets, covers.

[rickf]

Synthetic blend oils are still a petroleum base with synthetic additives. Full synthetic oil is a synthetic made base oil with all synthetic additives. That is why the full synthetic oils cost so much more. And the extra leaking bit is just another myth thanks to the internet. If your gaskets and seals are in good shape then one does not leak any more than another.