Diff juice?

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How often do you guys change the oil out on Darth Vader's nutsack ?

how often do you juice your's?  :D  and how thick is it?



thanks in advance

 
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I use 85w-90 synthetic in mine. It will last for years. The biggest culprit for those in humid and cool climates is condensation in the differential housing. After you drive yours pull the level check plug and look at the lube. If it's milky looking it's got water in it, good time to change it. And then take it for a drive to get it warmed up and dry out any remaining condensation.

If you can't remember when the last time was that it was changed, or if it's never been changed, now is a good time for a little spring cleaning.

 
Just remember that synthetic is not compatible with the trac-loc clutches.

I also encountered problems with a Detroit Tru-Trac and synthetic, When I finally reached a tech support at Detroit Tru-Trak, they admitted there is a problem with synthetic and the unit. They recommend removing it, wash it clean with brake / carb cleaner and reinstall/refill with real dino-oil.

 
I just had my rear axle taken apart and rebuilt with the addition of a Traction-Loc and all new bearings and seals. I posted on this before. The guy who rebuilt it and has been rebuilding all sorts of rear axles for more than 30 years, advises NOT to use Synthetic lube in an axle for the same reason the person who did my Top-Loader also advises not to use synthetic in a gear box. Synthetic definitely is a no-no with a Traction-Loc or similar type. I used Valvoline 80W90 lube in my axle and gearbox. Personally, while there are advantages with using synthetic oils in some applications, I choose to follow the advise of those who work, or have worked, with these older vehicles for decades.

 
I have no experience with the Tru Trac clutches, so I can't comment on them. I do have experience with multiple Ford Traction-lok units and Dana 44 style post-tracks as well as multiple top-loaders. The synthetic gear lubes work fine in all. Just use the proper lube for each application as you would for conventional lubes. The same goes for C4/C6. There is still a lot of smoke and mirrors out there regarding synthetic lubricants. Why that is so I don't know. Ford cars and trucks with Trac-Lok diffs have come from the factory with synthetic diff lube for many years. Please do your own research rather than relying on hearsay form me or anyone else. Trust but verify. Chuck

 
Our local rear rebuild shop stresses NO synthetic in the gear box. He stays busy doing warranty work for all the new car dealers. He had like a truck load of gear sets and bearings in a pile that had failed due to the synthetic. A few years ago I thought I would put synthetic Slick 50 gear oil in my F-150 and shortly after I did Boom the pinion bearing went out. Got another rear out of wreck and replace whole thing. 

Also put the friction modifier from Ford in when you go with normal rear grease with traction loc, again NO synthetic. Everything new is not always better.

 
Our local rear rebuild shop stresses NO synthetic in the gear box. He stays busy doing warranty work for all the new car dealers. He had like a truck load of gear sets and bearings in a pile that had failed due to the synthetic. A few years ago I thought I would put synthetic Slick 50 gear oil in my F-150 and shortly after I did Boom the pinion bearing went out. Got another rear out of wreck and replace whole thing. 

Also put the friction modifier from Ford in when you go with normal rear grease with traction loc, again NO synthetic. Everything new is not always better.
David, thank you for your comment which supports exactly what my guy(s) said about using synthetics in rear ends or gear boxes. However you may confuse people with your mention of "normal rear grease". I was also advised strongly to use only FORD friction modifier with the installation of the Traction Lok.

To each his or her own opinion when it comes to synthetic versus conventional oils, the debate continues........

 
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