daveman,

i can't remember exactly what they told me but the service adviser mentioned something about greasing up the slip yoke. when i took the mechanic out for a drive he mentioned they have lubed slip yokes before so i don't know what to tell ya...sorry

troy


maybe, i'll call in today to find out more info about it...

 

daveman,

i just got done talking on the phone to the service manager at the local ford garage. he told me they lubed the splines on my truck's slip yoke. and went on to say that it is relatively common for them to do that. he mentioned that they put grease on the splines at the factory during installation but sometimes not enough.

i asked whether i could look forward to future problems like you mentioned...and he didn't seem to think there would be any problems with my truck based on what they did. so, i don't know, guess i'll just keep driving it...

troy

 

Troy,

I didn't mean to imply you were doing anything wrong. I was just stating that if grease needed to be added, then there must be a lack of oil in the area of the bushing which should cause concern. The bushing and splines should be bathed in oil if the transmission's level is correct and the design allowed for that.

To me, the bushing that the yoke in running in must stay lubricated or failure is assured. If the dealer needed to add grease, then there must be a lack of oil.

The logic is this.

1. The yoke bushing must remain lubricated at all times.
2. The yoke bushing gets it's oil supply from the transmission fluid supply.
3. The yoke splines are in the exact same area as the bushing and therefore have the same oil supply.
4. If the splines need lubrication then the bushing must need it too and that worries me.

I'm not trying to alarm you, I'm just not following the logic.

What do you think of my logic?

~DM~

 

daveman,

nah, you didn't alarm me in the least.

your reasoning makes sense, but when i mentioned what you said to the service manager, he basically said not to worry about it and that "my friends" oughtta go to ford's mechanic school before they fill my head with jibberish!

it does seem that alot of ford folks complain about this same issue on their trucks...and the others prolly just don't even notice the shudder, unless it gets bad. interestingly enough, a co-worker of mine has a '99 ford superduty 4wd. he dropped me off at the dealership after work yesterday...and guess what...his truck shudders upon stopping, but he doesn't even realize it!

anyhoo, nuff of that. i'm just glad it doesn't shudder, or shake, rattle and roll anymore!!

peace

 

daveman,

quick question for ya regarding bushings...

the yoke bushing you talk about...is that different than say a suspension bushing?? just wondering since i know you don't have to lube suspension bushings...follow my logic?

troy

 

Troy,

The bushing I'm refering to is made of metals. The backing is usually made of steel and the wear surface inside is usually made of a very soft bearing material like an alloy of lead and tin. The bushing is pressed into the aluminum tail housing and then a rubber lip seal is pressed in after that. The drive shaft yoke has a precision OD with internal splines and the output shaft of the tranmission has the male spline. The slip yoke slides onto the male shaft and the OD is guided by the bushing exactly the same way as the bearing journals of a crankshaft in an engine.

BTW, a good many years back, I was a transmission expert and that was all I did when I was a mechanic. I used to see hundreds of transmissions per month while working for AAMCO and so I know a little bit about what I was talking about in case your ford dealer fills your head with more statements that your friends need to go to Ford school. I'm not one for going around telling folks to worry about something if I'm not certain I know what I'm talking about.

I'm glad that your problems went away but if grease fixed it, then it won't be long before that 300°F tranmission fluid will melt that grease and you'll be back to square one again. It just doesn't make sense to me, that's all I am saying and I know a thing or two about car and truck transmissions.

I'll do some more research on the bushing and how it gets it lubrication in my Ford maintenance CD and get back with you though.

Later,
~DM~

 

Thanks for the help Dave. I'm very interested in what you find out because I'm seemingly having similar problems with mine.

RP

 

daveman,

thanks for the info!!

i thought the service manager said they use some sort of special grease on the splines, but i'm not sure about the details. will be interesting to see what you come up with...

troy

 

daveman, help!!!

a guy over at another ford posting board claims the 4r70w has a seal that is not supposed to allow tranny fluid into the area where the slip yoke resides...but often times this inner seal lets some fluid past it, giving the impression that the fluid is used for lubing the yoke, when it really isn't!

let us all know as soon as you find anything out...there are some interested ears out here...!

 

Troy,

I've done some research and there appears to be no inner seal as your friend mentioned. Also, if there were an inner seal, then what would lubricate the bushing that the drive shaft runs on, don't tell me grease because there's no way that can work.

I've got drawings and cross section views of the entire 4R70W transmission and it appears exactly as I explained, I just can't figure out how to get those images to show up on this board. I may be able to take a digital picture and post that but it just seems too convoluted to take a picture of some image that is on my screen. I'll keep trying to figure out a way to snap a copy of the screen image in Windows and paste it into a docuement and then save that as a jpeg image.

Oh and Rock, you're welcomed but thus far it's just me and my beliefs until I can prove my point.

~DM~

 

Well Dave, why are you sitting here reading this post? GET TO IT! CHOP CHOP! Figure out all my problems and report back pronto. You'll be awarded with a large loaf of bread and a slab of balogna. No cheese yet. You'll have to figure out how to do handstands while farting the A B C's before you even get to look at a slice of Swiss.

It's a long shot but hey, you've come this far!

RP

 

daveman,

you are one diligent dude!!! i guess us thunkers are gonna have to worry about premature driveline wear, eh!

oh well, i'll prolly trade before the 3/36k warranty is up anyway...already kinda thinking that 300 plus hp 3v 5.4l in '03 is sounding real nice!! except it's gonna have a 4r75w behind it...with maybe the same issues?? but i'll have that new warranty...

 

Okay,

Check these images out and see if you guys see a seal that keeps transmission fluid from getting to the drive shaft yoke. These images will apply to almost any 2wd 4R70W. The 4wd version has it's output shaft connected to the transfer case and the output shaft for the drive shaft comes out on the other end of the transfer case. I looked at the details on the transfer case and they look very similar to the extension housing for the 2wd version.

I don't think you'll find a yoke seal but maybe I'm over looking it. Item 10 in the first image is the infamous drive shaft tail housing bushing. Item 11 in the second image is the tail housing busing seal to keep tranny fluid from leaking out since the area should have plenty of oil in that area during operation.





Hey Rock,

Here you go sire, I hope I didn't make you wait too long. Do I get to keep my head or is it to be off and in a basket?

~DM~

 

yeah, i don't see anything that looks like a seal. so how does the tranny fluid get back to the yoke? it doesn't look like it gets pumped back there. just splashed back there...?

 

Troy,

The oil gets back there during acceleration and from splash. Bear in mind that the views are for 2wd only so the 4wd version will require more images but if you trust me I won't have to post them. If the transmission oil level gets too low then that will reduce the amount that gets back to the bushing and yoke splines but I don't think that was your situation.

Again, I hope the grease helps you with your situation but I can't follow the logic. I may be wrong but I'm betting that I'm right and the grease will be a short term fix. I guess it might be possible that the dealer did some other work that they are not telling for possible legal reasons. However, I'm speculating at this point as to why they wouldn't disclose actual repair work to you.

Let's keep thinking and reviewing the possibilities as I've got the same issue with my truck and it partially drives me crazy too.

BTW, here is an excerpt from the transfer case section of the CD manual I've got.
"The transfer case is shifted either manually or electronically. The unit is lubricated by a positive displacement fluid pump that channels fluid flow through holes in the rear output shaft."

~DM~