Had a buddy's diff fail on him...

[LineArrayNut]

... was concerned about mine, have a sea-sense pump I could fish into the fill hole to do some flush and fills, on the Jeep in sig. what do y'all think? really don't want to pull covers, and was thinking some cheap 15W-40 ST diesel all fleet as flush and http://www.amazon.com/dp/B000IG7PMM/ref=pe_175190_21431760_M3T1_ST1_dp_1

as fill. What say y'all?

 

[bdcardinal]

How did it "fail"? Replacing fluid over and over will not make it come back to life. Besides pulling a cover is not difficult in the grand scheme of things.

 

[LineArrayNut]

He was using a 2wd midsize v6 dodge p'up as heavy tow vehicle, sheared gears, he's goin to a larger whole axle. I drive all my vehicles aggressively.

 

[MolaKule]

I have never seen a differential fail unless the diffy fluid was contaminated or lube level too low.

 

[Doog]

Originally Posted By: MolaKule
I have never seen a differential fail unless the diffy fluid was contaminated or lube level too low.


+1 mostly seal leaks over a long time.

 

[MolaKule]

I should have also added there was one failure not due to lube or lube contamination. At one time I had a ring and pinion failure in my HP Suburban and that was due to the bad metallurgy in a ring gear.

More specifically, the heat treatment was at fault.

The aftermarket gear supplier said the Lubricant failed to protect the teeth.

I had the drive pinion, ring gear, and pinion bearings sent to a metallurgical forensics lab in Wichita.

The lab found the Rockwell Hardness of all components to be below industry standards.

The aftermarket gear maker was sent the results and paid for the replacement parts, labor, analysis, and fluid.

 

[LineArrayNut]

neither he nor I will go quite that far in failure analysis; does due prudence seem that my OP will be enough/warranted?

 

[MolaKule]

I would use a good mineral or synthetic gear oil of say 75W90 to 75W110 and it would be anything but Lucas.

 

[LineArrayNut]

what's wrong w/ that particular (or any) lucas? already bought it... I can cut it w/ Rl D4 to lower visc or up it with M1 mPAO 65CST...

 

[Zaedock]

Originally Posted By: LineArrayNut
He was using a 2wd midsize v6 dodge p'up as heavy tow vehicle, sheared gears, he's goin to a larger whole axle. I drive all my vehicles aggressively.



I see diffs fail all the time in my sport.

Stripping a ring gear on an overloaded 8.25" axle shouldn't be surprising.

 

[Zaedock]

Originally Posted By: LineArrayNut
... was concerned about mine, have a sea-sense pump I could fish into the fill hole to do some flush and fills, on the Jeep in sig. what do y'all think? really don't want to pull covers, and was thinking some cheap 15W-40 ST diesel all fleet as flush and http://www.amazon.com/dp/B000IG7PMM/ref=pe_175190_21431760_M3T1_ST1_dp_1

as fill. What say y'all?



You either have a Dana35 or Aluminum Dana44.

Changing fluid on either will make no difference if you beat it.

 

[LineArrayNut]

pretty sure mines a 35 its a 5.2 L quadratrac 4wd w/ the tow package.

 

[Chris142]

Originally Posted By: LineArrayNut
and was thinking some cheap 15W-40 ST diesel all fleet as flush
Engine oils do not have the proper additives for Hypo id gears. I do not recommend that you use engine oil as a flush.

 

[Zaedock]

No point in doing a diff "flush". Save your $ on the motor oil and buy a tube of RTV. Pull the cover for inspection and replace with a few quarts of Supertech 80W90.

 

[bullwinkle]

Another problem would be an inability to get any metal out of (the bottom) of the housing, or to even look at the gears to see if a problem is developing. My '98 in my sig actually had RTV on its' covers when I got it, and gaskets were pretty cheap with an AAP code, along with the RP 75W90 Max-Gear I put in the front & rear.

 

[LineArrayNut]

have to clarify, this is for my KNOWN good axles not his KNOWN bad axle...

 

[Zaedock]

Originally Posted By: LineArrayNut
have to clarify, this is for my KNOWN good axles not his KNOWN bad axle...


A Dana35 is not a good axle

Seriously, change the lube and drive it. If you off road at all, make sure you carry spare axleshafts.

 

[dieselbass]

no noise? Pull the covers, check for making metal, apply black gasket maker to cover, reinstall cover, fill with gear lube of your choice(but not sta-lube) and enjoy. Just rebuilt Dana 60 front axle and runs nice and quiet. Shell 85-90 in for first 500 miles, amsoil in after that.

best of luck.

 

[MolaKule]

Quote:
what's wrong w/ that particular (or any) lucas? already bought it... I can cut it w/ Rl D4 to lower visc or up it with M1 mPAO 65CST...


I am simply saying it would have been my last choice.

Don't cut it with anything as you will reduce the EP additive that protects gearing and bearings.

I would take the cover off, wipe it out with a rag, and refill.

I prefer to coat a gasket with an RTV, apply the cover, and let it set and dry before refilling.

Also, I am not sure why you need a 75W140. If your vehicle specs a 75W140, then go for it, but a 75W110 is a good median weight for most differentials.

I know Amsoil and Lubrication Engineers (LE) both have gear oils in these viscosities.

 

[Hokiefyd]

Dad burned up the rear axle in an '89 Cherokee pulling a travel trailer across the country in the heat of the summer of '91. It failed in Michigan (California to Virginia trip). Good timing, because we were stopping there for a week to visit with mom's parents and family. I think a Jeep dealer in Grand Rapids replaced the axle under warranty.