Quote:
Originally Posted by nobb
Weird that as per the TSB, Toyota's most recent recommendation is to use MP grease on all joints except for the double cardan which is moly. Isn't a double cardan joint just two U-joints? How is it different in construction vs a U-joint to require (in theory) a different grease?
It seems the reason why Toyota initially specified two greases is because of the presence of sliding vs rolling forces. Rolling forces are better serviced by a (NLGI GC rated) MP grease and sliding forces by a (NLGI LB rated) moly grease. However, these days greases have become so good that most moly and MP greases are both GC and LB rated, so it might not really matter. All the old school guys saying moly greases ruined their U-joints were probably basing their experiences on ancient greases which did not perform the same in these two applications as compared to a modern grease.
I'm curious why Toyota would switch from a moly to a MP grease for the slip yoke when sliding forces are better serviced by a moly grease.
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I spent a while researching this as well because I have both a '99 and 2019 t4R, both 4x4. I was hoping the advice on the 2019 would be retroactive to the 1999 for some reason. I called a couple different entities but finally got the answer as to why the 5th gen recommendation was different from the 3rd gen. The guy at the Toyota Service Center told me Toyota uses a different metal compound in the 5th gen driveshafts. So those of you with the 5th gens don't NEED a moly lube but it's still recommended.
As for me, I'm going to have two guns, one with moly and one without. I honestly don't know why I spent so much effort trying to convince myself it's okay to use one grease on everything. An extra grease gun loaded with moly will cost me about $30 and will probably last the life of both cars. Trying to find a reason to use only one grease made me feel cheap and lazy. Having two guns will make me feel like a pro. And I kinda like that.
Change in grease recommendation
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