Gear oil for Explorer 8.8 with limited slip?

[ColoGuy]

I'm thinking a conventional 80W-90? Synthetics have been known to cause some noise with some LSDs I think. I seen that happen in my 2010 F-150 with LSD - limited slip differential. Of course there can often be different possible culprits to many challenges.

 

[shucker1]

Tag on mine says 75-140.

Plus 1\2 bottle of friction modifier.

I am running carbon fiber...

 

[ColoGuy]

Tag on mine says 75-140.

Plus 1\2 bottle of friction modifier.

I am running carbon fiber...

Now I'm confused. My "gear guy" used ~80W-140 for my truck locker and 80W-90 for the front posi. I think.

I think the Ford carbon fiber (more expensive) clutch kit has the 28 spline spring. The cheaper kit has the 31 spline spring. But either one works if you re-use the stock spring.

Makes some sense they would use 28 splines on Mustangs and 31 spines on F-150s. Think I decided the V-8 Explorer is 31 spline - when I was looking.

Can't argue with the manufacturer tag. Thanks. Back to the drawing board.

 

[shucker1]

Splines are actually on the shaft. The loading spring does not have any splines. Clutch packs engage the shaft and are pre-loaded by the S spring.

Stock LS rear end did not come with carbon fiber that I know of.

Carbon Fiber packs come from Ford Racing or other manufacturers.

Friction modifier actually makes the complete pack "Slip" a little bit around corners. I don't mind the extra bite so I cut back on friction modifier.

https://www.summitracing.com/parts/...tTv3BuC3Y5VnZt451sicifSaI9TKZkb8aAifTEALw_wcB

 

[RangerX]

Early nineties, Ford called for 80w90 in the 8.8. Other than gen2’s getting disc brakes, I don’t think your 97 8.8 is any different than my 93 and 94.
It might be somewhat better to use a higher number, but I think you’d be fine using 80/90 and a bottle of friction modifier if that’s what you want to run. My axle has a few hundred thou on it and seems to be doing okay.

 

[ColoGuy]

Splines are actually on the shaft. The loading spring does not have any splines. Clutch packs engage the shaft and are pre-loaded by the S spring.

Stock LS rear end did not come with carbon fiber that I know of.

Carbon Fiber packs come from Ford Racing or other manufacturers.

Friction modifier actually makes the complete pack "Slip" a little bit around corners. I don't mind the extra bite so I cut back on friction modifier.

https://www.summitracing.com/parts/...tTv3BuC3Y5VnZt451sicifSaI9TKZkb8aAifTEALw_wcB

The spring is a different size for the 28 spline vs the 31 spline.

 

[ColoGuy]

Early nineties, Ford called for 80w90 in the 8.8. Other than gen2’s getting disc brakes, I don’t think your 97 8.8 is any different than my 93 and 94.
It might be somewhat better to use a higher number, but I think you’d be fine using 80/90 and a bottle of friction modifier if that’s what you want to run. My axle has a few hundred thou on it and seems to be doing okay.

Was kind of thinking that here - I think axles often take about 3 quarts so I'm considering ~3 gallons of 80W90 for limited slip. The bottles that specify limited slip must have some type of friction modifier or they wouldn't claim to be for limited slip. But then I expect logic to prevail and am disappointed at times.

I've also never heard of properly lubed gears wearing out. I think it is best to change the oil similar to a transmission (~75,000 miles) but likely not necessary. With LSD differentials needing more care than common slip diffs. Though it is the clutch packs that wear out from ordinary wear and tear more than anything, I've heard average life is about 100,000 miles and that surely varies tremendously.

 

[Blown]

Durablend gear oil?

 

[ColoGuy]

Well this is just pathetic. Valvoline is advertising a bottle for limited slip and customers receive regular oil. Plus the Amazon site would not allow me to load a note/question regarding that. They are aware - they do not care from appearances. https://www.amazon.com/Valvoline-VV...001OV61KW/ref=cm_cr_arp_d_product_top?ie=UTF8

I've been mislead by advertising on Amazon at least as much as Ebay. More I think. That can be expensive with auto parts.

 

[SWIGIN]

Wow, all this over gear oil.

If you fill it with any oil made for rear ends it will be fine. If you fill it with oil with no friction modifier in it then add some if you wish. If you add some that already has FM in it then don't add any....or go ahead and add more.

It really don't matter.

 

[ColoGuy]

Wow, all this over gear oil.

If you fill it with any oil made for rear ends it will be fine. If you fill it with oil with no friction modifier in it then add some if you wish. If you add some that already has FM in it then don't add any....or go ahead and add more.

It really don't matter.

Arguing that oil, any oil, is not important would make a lot of engineers and mechanics consider tossing a 3/4" torque wrench in your direction.

A number of us are gear heads with a stable of autos, many with limited slip - I have six with limited slip and/or lockers. So yea - gear oil is pretty important to some of us.

Had an old and odd assortment of gear oil. Bought four gallons of this stuff: https://www.amazon.com/gp/product/B000M8RYOK/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

GL-5 rating should satisfy most axles.

Synthetics are noted for producing noise in many axles - like my F-150. Shame, rather a fan of synthetics as a rule.

 

[SWIGIN]

And some of us have rebuilt rears for over 20 years so don't think I'm a newb just spouting off.

 

[donalds]

Wow.... 75-140 full synthetic mobile 1 gear oil and a half a bottle of xl3 friction modifier add the other half if it's noisy while cornering add the other half that's it my.2¢

 

[ColoGuy]

And some of us have rebuilt rears for over 20 years so don't think I'm a newb just spouting off.

My gear guy uses the cheapest oil he can get his hands on. Related? Doesn't mean that its the best lubricant. There is no way that it is anything more than generally adequate. I've known experienced mechanics who hated synthetic oil - my brother would not accept a case as a gift. Experience equates to experience. That equation contains nothing else.

 

[donalds]

That's ford spec if it's build right then it won't leak
Plus with synthetic you will get better gas mileage again synthetic is ford spec

Don't anger the ford God's . Put the correct fluids in your truck

 

[shucker1]

 

[ColoGuy]

That's ford spec if it's build right then it won't leak
Plus with synthetic you will get better gas mileage again synthetic is ford spec

Don't anger the ford God's . Put the correct fluids in your truck

I got axle noise when using synthetic on my F-150 - going to remove it for that reason. Have seen that mentioned many times.

Thought it would be a good idea to ask Explorer owners. Seems that few are really into axle lubricant. Understandable - it is hardly mentioned anywhere at all. I'd almost bet that most people have never had axle oil changed once.

Who does their own gear work? Not many.

Worked out fine I think. Pretty sure the product I bought is a solid choice. Still an "educated guess" of sorts.

 

[SWIGIN]

My gear guy uses the cheapest oil he can get his hands on. Related? Doesn't mean that its the best lubricant. There is no way that it is anything more than generally adequate. I've known experienced mechanics who hated synthetic oil - my brother would not accept a case as a gift. Experience equates to experience. That equation contains nothing else.

Hold on there captain gear head, are you saying I use the cheapest thing I can find?

You'd be wrong, but is there anything wrong with that....no.

At one time basic cheap gear oil was speced for the 8.8 then the spec went to synthetic. So like I said, anything you throw in it will be fine with or without additive.

The only reason your rear got noisy with synthetic is because the thinner fluid dampens sound less then thick oil. But both are 100% OK to run for years.

 

[96eb96]

After installing the CF, I had noise with Valvoline and the built in modifier. It was a bit noisy in slow, tight turns (like a figure 8).
So I added 1/2 bottle of the ford friction modifier, got much better. Then a bit more, the noise is gone and it works great. CF is very aggressive and standard clutch packs may be ok with just what is in the gear oil bottle.

I use it off road sometimes and the LS makes a big difference, even in 4wd. Also in the snow. It would not move in the snow with the open in 2wd. Exes are very light in the back.

 

[koda2000]

My 2 cents...

Differential design has not changed since the 60's (and maybe the 50's). 80W90 was the go-to weight for diffs for many, many years. It obviously worked then and would still work today.

Synthetic oils in general are better than conventional oils. They last longer and can suspend more debris and are more resistant to breaking down due to heat.

Our Explorer's are not performance vehicles and are more likely to be used for towing. Ford's recommendation for diff oil is 80W90 conventional for the front diff and 75W140 for the rear diff (with Ford friction modifier if rear LS). Ford claims that the rear diff fluid is "life time" (which is bullsh*t). If you want your rear diff to last you should replace the fluid every 30K-50K.

As far as noise with LS rear diffs, experience has taught us that even if you use a gear oil that already has a friction modifier in it, you should still add the Ford friction modifier to it to fully eliminate chatter and noise.

Is 80W90 conventional better than a synthetic gear oil? I think either can be used successfully, but you still need to use a friction modifier if LS, and I'd recommend not exceeding around 30K between oil changes if using conventional.

It puzzles me as to why people think they know better than the engineer's regarding what lubricants are best to use in their daily drivers? I use the recommended lubricants in my 200,000 mile '01 EB 5.0L, but on my 200K POS '01 ST and my '00 5.0L Mountaineer, which is now nearing 300,000 miles, I recently replaced the rear diff fluid (due to a broken axle on one and a leaking pinion seal on the other) with conventional 80W90 because IMO they don't justify spending the $60+ cost of synthetic 75W145.

If you think you know better which lubricant is better for your truck and its intended use then use it, but why waste everyone's time here arguing about what's best when you've apparently already made up your mind.

JMO