Grease Selection on Driveshaft Application, Toyota

[nobb]

For my older Toyota 4Runner, the original manual calls for the following greases on the driveshaft lube points:

Slip yoke: Molybdenum based NLGI grade 2
Double cardan joint: Molybdenum based NLGI grade 2
U-joints: Multipurpose lithium based NLGI grade 2

Then they issued a TSB stating the following:

Slip yoke: Multipurpose lithium based NLGI grade 2
Double cardan joint: Molybdenum based NLGI grade 2
U-joints: Multipurpose lithium based NLGI grade 2

Does anyone know why they might have changed the double cardan from a moly to MP grease? Is a double cardan joint not essentially just two U-joints? Why would they require different greases?

In general, what are your thoughts on what the proper grease is for the various driveshaft lube points? There still appears to be controversy on using moly based greases on bearing applications (like the U joint). I noticed older greases might only be rated GC or LB (chassis vs bearing), of which I am guessing that could be why Toyota specified a different grease on each point. However, almost all modern greases, moly or not, are dual rated GB-LB so is there any real reason to use a different grease on each lube point?

If a modern good quality grease such as the popular Mystik High Temp JT6 is dual rated GC-LB, is there any reason why this can't be used in place of a moly grease? Often times I see high quality MP greases having better Timken load, wear/weld numbers than some moly greases.

 

[Astro14]

On my 1990 4 Runner, I have used, variously, Mobil 1 (which is a great product) and Valvoline synthetic (which does have moly). Front driveshaft is still good. Just did the u joints on the rear for the first time at 270,000 miles...

The double cardan has always required a moly grease.

What I think is interesting is the removal of the moly requirement on the slip joint. I've just used what's in the gun on everything.

 

[supton]

Is it a case where moly is the better stuff; but is not strictly required for the double cardan? Like they specified the minimum requirement for the grease, not a "use only this".

Dunno. When I asked around about this, the only consensus I got was "I just use the same moly #2 for everything, and never have a problem".

 

[SZR48207]

Do you have the TSB part correct? It still says the double cards uses moly.

Anyway, the general rule is that moly and roller bearings like in a u joint don't mix. Moly can cause flat spotting on the rollers because it doesn't permit them to spin during operation.

However moly on the slip yoke is fine. Sliding forces can benefit from moly.

The thing is, just how often are you going to disassemble the drive shaft in order to lube the slip yoke?

On my Taco I have one grease gun filled with a non moly synthetic. This is what I use on all the zerks on the drive line that I can get to while the truck is parked.

If I ever take off the driveshaft I'll apply some moly grease by hand before reinstall.

 

[nobb]

Originally Posted By: Reddy45
Do you have the TSB part correct? It still says the double cards uses moly.


As per the TSB, what changed is that now, only the double cardan uses moly. The slip yoke changed from moly to MP. I'm curious why that is.

For the double cardan joint, I thought that it's just two U-joints, so why do they spec moly on the double cardan and MP on U-joints?

 

[Trav]

Is it a joint like this? If it is there is a U joint zerk and a cardan zerk. It looks like 2 different animals.



The slip yoke is what got me confused, generally they use a high (5%+) moly content grease or in the case of some Fords a Krytox based lube

 

[SZR48207]

Originally Posted By: nobb
Originally Posted By: Reddy45
Do you have the TSB part correct? It still says the double cards uses moly.


As per the TSB, what changed is that now, only the double cardan uses moly. The slip yoke changed from moly to MP. I'm curious why that is.

For the double cardan joint, I thought that it's just two U-joints, so why do they spec moly on the double cardan and MP on U-joints?


If that is the case then it seems odd. You might check the FSM for a newer 4runner or Tacoma as I think the wording now says moly lube on the yoke and non moly on everything else. It's not like the parts are any different now, but I would think that Toyota would have become wiser over the years.

Anyway, yes a double cardan is just two u joints. It wouldn't make sense to use a moly based lube on one.

If you want to go really simple, get a MP grease that has a small (Lincoln/Mercury grease which has that formulation and specs it's use on everything but the slip yoke (for which case they have a special blue Teflon based lube that prevents drive line clunk).

 

[Trav]

Originally Posted By: Reddy45

Anyway, yes a double cardan is just two u joints. It wouldn't make sense to use a moly based lube on one.


Maybe not, did you look at the picture of a 4 runner rear shaft double cardan above? This needs moly in the cardan zerk.l

 

[KingCake]

I work on lots of toyotas. Seen lots of bad double cardans on tacomas. The other problem is the slip yoke likes to hydro-lock with grease and pogo the drivetrain.

What I do is give the slip yoke 4-6 pumps of NLGI 1.5 grease (Tractor supply has it in tubes) -- It works through the slip yoke splines easier. No pogo stick.

Everything else gets ford chassis grease. Best grease you can get. Moly + Polyethylene.

I've had vehicles with repeat driveshaft failures never come back after starting them on this protocol.

 

[SargeBB]

Toyota's recommendation for driveshaft (propeller shaft) lubrication is confusing. Ref: the double caradan joint: This joint has 3 zerks. The middle joint only should be lubricated with moly grease. The zerk immediately before and the zerk immediately after the middle zerk both lubricate the two universal joints contained within the double caradan. Therefore, they should be lubricated with the same non-moly grease you use on the other universal joints on the propeller shaft. Mystik JT-6 Hi-Temp Lithium Complex was mentioned in a previous post. It would be an excellent choice as it meets Spicer's U-joint specs. The slip yoke can use either the moly or the non-moly. Toyota allows either, dependent on the model year. Personally, because of the function of the slip yoke, I use the same moly on that particular zerk that I use on the middle zerk on the double caradan. I use only a non-moly Lithium Complex #2 on all universal joints.