Those front diff zerks....

I was doing some routine maintenance on the truck today and struggling with greasing the second zerk from the front (as usual). It got me wondering, since I typically only use 4x4 once a month to lube the system, how often do these front zerks really need to be greased?

Also, has anyone found a way to make greasing that second zerk any easier? My Locknlube doesn't fit in there, and getting around that shield is always a pain.

Apologies if its been asked before. I've spent about an hour searching without finding anything.

 

I hate greasable joints. It probably isn’t what most would do, but I likely would remove the driveshaft and swap to the sealed joints that the later models were equipped with and never have to worry about greasing again.

For greasing yours, I have seen YouTubers do their driveshaft maintenance and post it. You might check out some of those videos and see if they list what grease gun worked for them. As for grease schedule, every oil change would probably be fine. The owner’s manual should tell you when to grease the “propeller shaft” joints, which would be the best thing to listen to.

 

I have a 2nd gen, but I imagine 3rd gen is pretty much the same. Driveline grease fittings are a PITA. The chance of them not being blocked by the U joint is close to zero, so this is how I do it.

On tire rotation day

1. Jack up the back of the truck and put 2 jack stands under the rear axle so both tires are off the ground.
2. jack up the front so both tires are off the ground. (FYI I do it in a way that would give the safety nannies fits. You of course will use the appropriate jack stands and wear the appropriate safety gear, and have an OSHA inspector on site to check your every move lol)
3. do the tire rotation
4. when that's done put the truck in neutral and release the parking brake
5. get under the truck and turn the drive shafts so the grease gun can get onto the zerk
6. grease everything that looks like a zerk
7. put the truck in park and set the parking brake
8. lower the front
9. lower the rear
10. clean up the mess
11. Beer

 

My front and rear don't have any zerks but on other/older 4x4 the grease gun's needle worked the best to get in tight spaces, just hold it tight against the zerk to depress the valve.

 

I remove the shield with a 12MM wrench which makes it easier to reach. I lube all 5 of my Zerks every oil change. That may be overkill but I would rather see my Zerks purge than have them be dry. Here is a good thread on Zerks

https://www.tacomaworld.com/threads/check-your-u-joints.409042/

 

I just greased my 2 front zerks this afternoon. I took off the heat shield, it is just 2 bolts size 12mm I think. It wasnt too hard to get the hose lock to attach but I did have to try a couple times.

 

5 zerks? I think I only have 2 on my 18.

 

Early 2016 4x4s shipped with 5 Zerks. Around summer of 2016 the rear shaft had non-greaseable joints.

Around 2019 is the front shaft went to non-greaseable joints.

 

I installed that Miller Cat shield on my 2018. Can't get to the front drive shaft grease fittings now. Haven't greased them in 20K+ miles. Don't use front wheel drive (except very infrequently during the winter here) or at least once a month for a very brief period to just cycle the transfer case shifting mechanism.

So... when I get ready to change out my transmission fluid at 60K (currently at 35K) I'll drop the Miller Cat shield and then grease them. I think they'll still be ok.

 

Keep in mind, the driveshaft spins even while in 2wd. 35k is a loooong stretch for lack of lube

 

It shouldn’t really spin at all unless there is friction in the transfer case. That’s the whole point of the ADD.

 

ok…… guess I misunderstood the system

 

This is what I ended up using for the front. The lock n lube won't fit. This one was from AutoZone

 

I always used a grease needle adapter when I had the 2nd gens, which is the exact same setup as older 3rd gens. Worked well.

 

I got rid of my Lock N Lube just because of this. Dont have enough grease fittings in my regular schedule to make it worth the hassle

On 2nd gens if you rotate the front prop shaft just right, you can snake a regular grease gun in there. It sucks, but once a year isn't the end of the world

 

I wish I had non-greaseable joints. I keep my 5 Zerks greased because of this:

“Bottom line on strength: The non-greaseable joint is slightly stronger than a greaseable joint. The exact number, how much stronger, is unknown and we do not believe it to be very significant.

Bottom line on wear life: A regularly greased greaseable joint will outlive a non-greaseable joint. But a non-greaseable joint will outlive a greaseable joint that does not get greased properly.”

https://4xshaft.com/blogs/faq/greaseable-vs-non-greaseable-joints-which-is-better#:~:text=Bottom%20line%20on%20strength%3A%20The,outlive%20a%20non%2Dgreaseable%20joint.

 

I'll have to try removing that shield and see if I can find my needle for next time. I just hate that I have to drop my rear skid plate to get the shield off, though. Such a hassle just to grease one zerk.

From what I've been told, it does actually spin slowly while in 2WD. Something about centrifugal force or whatever.

 

The sprocket in the transfer case on the main shaft that the chain rides on will freewheel on the mainshaft. When 4WD is selected, the shift fork engages that sprocket to a fixed gear on the mainshaft, locking the two together. In 2WD, the only way the driveshaft could be spinning is if friction in the transfer case is high enough to turn that sprocket, chain, and correspondingly the front driveshaft. The front driveshaft is decently heavy enough that I would be surprised if it actually turns from transfer case friction.

It physically cannot spin from the front wheels spinning, as the ADD disengaging the right wheel takes care of that. As such, the left wheel drives the spider gears which rotate the inner right shaft backwards, and the differential case itself sits still as the spiders spin.

 

Sealed joints don't last forever. Their expected lifetime is 100k miles before needing to be replaced. However greasable joints, if maintained properly WILL last forever. I'd take that option every day of the week.

 

Great, I wouldn't. Expected lifetime is one thing, doesn't mean most of them don't go significantly longer though. I have had over 200K on sealed u-joints with still no play at all. I don't lift vehicles. At stock height, I have never worn a joint out.

Expected lifetime in mileage also doesn't say much when different vehicles have different loads and driveline speeds. What driveline speed and vehicle load are they basing 100K off of? No one knows, so it doesn't mean a lot. I find I have trouble with carrier bearings before u-joints anyways.