I wonder if this grease fitting mod can be done to the slip yoke that slips into the transmission. Mine has about 3/4'' of slip yoke that is dirty and rusty, not nice and clean like what actually goes into the transmission. Leading me to believe this 3/4'' is an adequate place to install a grease fitting. Is their any reason why this would be a bad idea?

 

If it's an automatic, there's tranny fluid inside there, so no need to grease it

And if it's a manual, well, I think there's still gear fluid there.

 

Im getting some clunk noises and im wondering if the tranny fluid is enough lub. its an f150 btw. 2wd 1994.

 

You will never have a lube problem with a yoke that goes into the tailhousing of a stick or auto. It's all loose tranny lube in front of the seal.

 

I hadn't seen the write up, but had heard mention if this a few times. It was simple enough that I didn't have any trouble doing it on my own.

When I pulled it apart initially, I examined the inside and realized that the grease wasn't pushed all the way into the female side of the slip yolk - meaning that it never completely compressed. From there it was pretty easy to measure to that point - and make sure to place the grease fitting at the top of the stroke. My reasoning was that withe enough grease up top... in a part that spins at high speed, the grease would likely spread out on it's own.

I greased it when I put it together, so I honestly don't know how much this placement actually helps - but I'll be sure to report back next time it needs grease. (although, the whole point is to make it easy enough to catch this fitting when i do the rest of the truck as regular maintenance - that hopefully no more clunk ever.)

edit: Nice work on the write up though. :-) Good post.

 

GM's have had grease fitting all over their front suspensions for years. I've replaced more front end parts on them than I care to discuss.
JL

 

Well then what im feeling on the truck is probably just my tranny getting ready to leave me......sigh.....

 

My wife's 02 F-150 had the clunk and no slip yoke. I dropped the drive shaft and greased the splines on the yoke that go into the tail shaft on the trans, put it back together and 3000 miles later the clunk has not returned.

 

I have been planning on doing this mod, but am now re-thinking the issue again. I had to take my drive shaft to a drive-line shop to have the center carrier bearing removed and replaced, and talked with the tech about the zerk mod. He suggested NOT doing it because there is no relief point for excess grease to flow to, and if the end space beyond the shaft gets packed with grease, it will be possible to push out the plug that rides right behind the u-joint. What I'm wondering, thogh, is whether or nto there is enough open space for the grease to slowly migrate out between teh splines and into the boot as a relief point. Still, I see his point and it does seem like something worthy of more thought and consideration.

Furthermore, Spicer makes an adapter piece that can be used on our drive shafts to replace the boot, and it is simply a press on seal cap that has a zerk built into it (does not require a hydraulic press, either). According to this mechanic who's been repairing and building drive shafts for over 35 years, even the Spicer adapter will not be as durable as the original boot, and recommended that I simply leave it alone as long as everything is moving fine and the boot is in good condition.

Having received this input from an experienced drive-line mechanic, I'll have to think on this a while longer now.

 

skoveng - Any further update? Are things still smooth? Have you needed to add more grease?

Trying to figure out if I should get my slip joint greased on my 2008 - getting the thump at starts/stops after things are warmed up.

Thanks for all the great info.

 

[quote=F250_;8076192]I have been planning on doing this mod, but am now re-thinking the issue again. I had to take my drive shaft to a drive-line shop to have the center carrier bearing removed and replaced, and talked with the tech about the zerk mod. He suggested NOT doing it because there is no relief point for excess grease to flow to, and if the end space beyond the shaft gets packed with grease, it will be possible to push out the plug that rides right behind the u-joint. What I'm wondering, thogh, is whether or nto there is enough open space for the grease to slowly migrate out between teh splines and into the boot as a relief point. Still, I see his point and it does seem like something worthy of more thought and consideration.

Furthermore, Spicer makes an adapter piece that can be used on our drive shafts to replace the boot, and it is simply a press on seal cap that has a zerk built into it (does not require a hydraulic press, either). According to this mechanic who's been repairing and building drive shafts for over 35 years, even the Spicer adapter will not be as durable as the original boot, and recommended that I simply leave it alone as long as everything is moving fine and the boot is in good condition.

Having received this input from an experienced drive-line mechanic, I'll have to think on this a while longer now.[/quote]


Yep, you can't beat experience. I would think the yoke greasing event would only take place once or never....................waste of time.

 

[QUOTE=EXv10;8815158]I assume you have never heard an experienced tech give out bad information.
There is plenty of clearance in the yoke splines to relieve the grease pressure.
If there wasn't enough clearance, you would not have an easy slip fit.

 

I'm here to provide an up-date on the slip-yoke grease fitting modification.

First, I have not had any problems with the drive line with respects to the yoke end not having a relief vent hole. Once you start having the problem of the "clunking", the blue plastic coating is worn off of the splines, providing plenty of room for any excess grease to find its way out.

I have only been greasing the yoke when I notice the clunking returning during a pull-out from a stop. For me, it's about every 7 to 10K miles.

When greasing, using a standard level-style manual grease gun, I pump about 20 times.
I have about 20K miles on the truck since the modification and have not noticed any grease leaking from the spline boot.

I'm happy with the mod as the clunking when pulling out drives me nuts and ruins the joy of driving the truck.

I'll keep everyone posted at the miles roll on.

 

While I totally agree with you, the above statement is not necessarily true. In my case, the plastic coating was perfect, it just didn't have enough grease.

 

Same here. I'm still debating on putting the grease fitting in or not. I guess I'll decide next time I have to grease the slip yoke. My re-greasing has held up really well -- it'll be 2yrs in July, around 20k miles so far.