Differential flush?

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Not sure if this where to post this question, if not here mods please move the thread.

What I was wondering is if any do a differential flush to get rid of any metal flakes, dirt, varnish, sludge buildup, etc after draining the used diff gear oil and if so what is the good flush medium for this; MMO, ATF, some clean gear oil, other? Thanks.

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Fill with the proper viscosity and fluid type and drain in 5k.

I would not put anything in a diffy that thins the oil.
 
Originally Posted By: MolaKule
Fill with the proper viscosity and fluid type and drain in 5k.

I would not put anything in a diffy that thins the oil.
ditto!!!
 
Hi,
in changing from a sulfur based mineral lubricant to a synthetic lubricant it was common practice to flush the differential with a 50/50 mix of kerosine and the new lubricant. The differential was spun without load for about 10 minutes in this case

This always worked very well
 
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I recently did a Auto-Rx flush on my 2000 Tundra rear diff with 144K on it. I added 6 ozs of ARX to a 3.1 qt sump. ARX is a blend of cleaning esters and not a solvent, so I was comfortable using it in the diff. I'm not sure what the viscosity of ARX is by itself, but I'd say it's probably pretty close to the SAE 90 LE 607 that I was using it with. After driving 1000 miles, I drained the diff and replaced the gear oil with LE's new 1605 SAE 110. I don't know what benefit I gained by doing this cleaning, but I wanted to provide a sparkling clean environment for the new gear oil I was going to use. So far, so good with the new fill.
 
Help me out here, please.

What's wrong with draining the OEM gear lube at 5k miles and replacing it with something like Severe Gear 75w-90 (or any other high quality syn gear lube)? No Auto-Rx (though I use it for cleaning and maintenance in the engine), no kerosene flushes, etc. Just replace it with high quality syn gear lube.

Even at 19k miles as Dale Knight indicated above with his ride. No flush, no worries!
 
I have never done anything except drain and refill gear oil in the past. But, up until recently, I never knew about ARX. The first time I ever tried it was on my Tundra. When I first read your post, I thought you would be just fine draining your OEM fill and replacing it with SG. But then I think back to all the OEM fills I've drained, even at 5K miles, and remember how clumpy and dirty the OEM fills were and how much sludge and metal were on the drain plugs. As I reconsider about my past gear oil maintenance practices, I think the OEM fill would have been the perfect time to do a ARX treatment and then never look back.
 
I always took the cover off, and blasted everything with brake cleaner. Then I waited for it to dry, and then I sealed the cover and put it back on. Once the RTV was dry, I simply put in the new gear oil and the limited slip additive if it was needed.

Most of the other guys I have worked with do the same thing.

now I have good advice on what to do with the diffs that have no removable cover.
 
Hi,
dkryan - You are correct. It is unwise to leave "sulphur" based gear lubricants in place longer than around 5k miles if changing to a modern synthetic. The longer in distance the move is left the greater the risk of seal seepage and etc. (EatonFuller and my own experience)
 
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The magnetic dipstick on the Mag-Hytec covers is a boon in this area. After doing a series of oil changes for temperature tests (4 in fairly rapid succession) the dipstick still had picked up a gob of particles when I checked it about 5K later. I installed a limited slip at the same time with new carrier bearings, so some of that was probably break-in metal from the bearings, but one would think the successive drains and refills would have eliminated a lot of that. I started checking it more often after and the amount was gradually reduced to almost nothing over time. I'll be installing one of these covers on my newer '05 truck (now with 9K) in a coupla weeks and installing fresh synthetic. It will be interesting to see how much stuff it catches. I imagine a small magnet epoxied to the inside of the diff cover might achieve the same thing.
 
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