Rear Differential Gear Lube

I know many of us like using the dino gear lubes, and I have been too.
I've been using Lucas 85w-140.
Mopar does still recommend synthetics.
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Ya I should make a video of the 85w-140 after sitting in the bottle when it is below freezing outside. It a sticky goop that has the consistency of Jello LOL..
I am experiencing a sticky Trac lok diff and seems to take a long time to warm up, when it is cold outside.
My next test is to mix these 2 together in a glass and see what happens.
Would like to free the diff up a bit and I think the lighter synthetic and the heavy duty dino may work well together?
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So We may end up trying 50-50 of each in a test glass and see how they react together frozen...ha ha..
Any thoughts on this?

I've tried both dino and synthetics at full strength and with the appropriate modifiers for my Trac-Lok and never noticed a difference. We can get single digit (F) where I am (not this year). I only use the dino now and I don't tow so I use the 75-90 or 80-90. That's what my Ranger and Subaru call for so I only need one flavor for all.

I like your experiment. Sounds interesting.

I read many times to never mix oils. IMO: use one or the other not both!

Maybe trac lock is the problem not the oil ??

Just use regular old Dino
I would not mix them
If it worked someone would already be selling it as the greatest product to ever hit the streets of Moshi.......:gr_grin:

Ya.. but how much fun is that? Time for TC's kitchen lab test results!
First off IDK what the heck is in the Dino Lucas 85w-140, but anyone who had used this stuff knows it sticks to gears, like nothing else out there. = excellent protection.
The Lucas dino 85w-140 is very similar to a blue bottle of STP oil additive, when it comes to sticky.

So...

Ok so it is about a 75 % dino & 25 % synthetic mixture, which can be played with.
You can feel the difference in flow rate and clarity in the synthetic.
Pics are from video screen shots, oh well..
Ok I am impressed, even cold it mixed well together..
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No pic but mixture was then heated to 150F as in warming up the gears and then was stirred very well again.
Anyways after 2 hours back into the freezer. The mixing is good with the lube so far, no separating back to a thick solid onto the bottom after 2 hours.
I think I may go with 40 % synthetic and 60 of the much thicker dino.
Freezer test next after 10 hours

Ok, we got a "TC is the oil guy" thread. Interesting .


I have been using dino. I know diff oil can get thick especially in cold weather. But here's the thing. When I warm up the Jeep and it is real cold out I like to only let the engine run for a minute and then "drive it" slowly at first through town because that warms up the entire drive train diffs and all before I get on it on the interstate. That's just me and what I do.


Good interesting thread, TC.


Dave

x2. I think there's enough of an oil film on things to protect it while it warms up. But it's fun to experiment!

The mixed Lucas gear lube is out of the freezer after 10 hours.(close enough)
Click on image to see video:
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The synthetic has increased flow even at 25% synthetic & 75% Dino.
It remains mixed perfectly. Looks like I now have created a quality semi-synthetic!!
Probably a 60% synthetic /40% Dino will get mixed, for the in Jeep testing.
Keep in in mind I do tow, & that alone the the 85w-140 is way too thick when cold.
I believe this mixture will free up the diff when cold, and may even offer better MPG?
Of course the Mopar limited slip additive, will be used for the Trac-lok...
Future results after installation, will follow in the future.....:gr_grin:

Really need to also check to see if there are any additives between the 2 that may react badly when mixed long term.
I don't see that small amount helping much with gas mileage in the grand scheme of things.
I'll take the 85-140 and deal with minor thickness until its warmed up for the protection.

Good question to ask on the oil forum.

You'll be fine since they do make synthetic blend gear oil.

lol just use Slick 50 and youll never have to worry about oil lube again!

or install a heater on the carrier and the dino will be fine at 0 degs

my ram also has the same recommendation on 75w140, I got -38 C this morning, it was also thick / frozen.

have a look for some 80w140 grades to add to your comparison, probably what i'm going with next. 75w90 is more expensive than 75w140 in my neck of the woods.

Why not just go with 75w-90 synthetic if you're not towing then?

anything new w/ your experiment?

Yes as a matter of fact..
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Got some new Lucas Dino 85w-140, then mixed it with the 75w-90 synthetic and left in freezer now for 2 days.
Looks like 60 percent Dino & 40 percent synthetic is a perfect flow rate.

ouch. didn't think synthetic was that expensive.
I'm planning to go up to 85w-140 from 80w-90 and I guess I'll split 1 quart of synthetic between the 2 diffs. it'll probably be more like 70-30 ratio.
Just to cover myself for the "cold" AZ places in the future.

Update-Recap and Good Results!

One problem got solved today a very sluggish 8.25 rear diff.
Been running Lucas 85w-140, dino gear lube.
Even when it wasn't super cold the trac-lok would take forever to warm up, and was almost like the brakes were dragging to get going, especially uphill.
My brakes were checked and they were fine, and released properly.
When it was below freezing, it was terrible.
The last two diff lube changes @ 10k miles also produced some sludge noticeable along bottom at magnet area, at the bottom of housing.
The Lucas is pretty sticky stuff & protects the gears well.
OE specs recommend synthetics I suppose for fuel mileage. I think dino protects the gears better.

Today a compromise was reached by using Lucas 1.6 litres of dino 85w-140 and 1 Litre of the thinner Lucas 75w-90 synthetic, for larger Riddler cover.
This created a semi-synthetic mixture approximately 60% dino and 40 % 75w-90 synthetic with the 4oz of Mopar limited slip additive.
OEM stamped cover would take slightly above 2 litres of gear lube normally.
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Darn camera phone -color off- lube not green it was light brownish.
I had wiped away some sludge around magnet & no metal particles found, which is good!

Installed cover, took it for a slow city drive, ya what a difference!
Sluggishness pretty much immediately gone at 41F. :gr_grin:
I then drove on the highway for about 1/2 hour, hoping the 40% synthetics would work their way thru everything, and all is good now.

No sticking, not sluggish, I wonder if the synthetics will clean better and leave any sludge now?
Time will tell on the next cover pull.
A further report will be added to confirm the real cold results in the future.
I expect the semi-synthetic blend to now flow right finally, as tested previously from freezer results. :happy107:

Just to let you know the Riddler cover(as with almost all aftermarket covers) do not spec more gear oil.

Yes the plug is higher but that is to compensate for the added tilt of the rear diff after lifting to make sure you can still get the OE spec amount of fluid in.

Adding to much fluid will spit it out the diff breather or axle seals(once the diff breather get's clogged).

tjkj2002 said:

Just to let you know the Riddler cover(as with almost all aftermarket covers) do not spec more gear oil.

Yes the plug is higher but that is to compensate for the added tilt of the rear diff after lifting to make sure you can still get the OE spec amount of fluid in.

Adding to much fluid will spit it out the diff breather or axle seals(once the diff breather get's clogged).

Click to expand...

Yes seen it happen when people over fill