truck is 2wd and driveshaft seems to be a one-piece type because it goes from the differential straight into the transmission. anyway, i was wondering if the clunk im experiencing whenever i press on the clutch might possibly be that flange attached onto the driveshaft that goes into the transmission. i asked a local 4WP if they could grease the "slip yoke" because that's what i thought it was called, but the tech said i dont have a slip yoke. then he goes saying that the "flange" is lubricated via the transmission fluid. i called my service manager and confirmed indeed that it was a "flange" type, but he did suggest however to try and grease and even gave me a part number for this special grease. any ideas? if it is indeed greasable, what nut type/size do i use to take off the driveshaft? thanks.

 

First off, you are probably talking about the Cardan joints (universal joints). The ones from Ford at least from 2004-2008 are NOT serviceable/grease-able.

Secondly, if they were grease-able u-joints, you'd see a Zerk fitting for a grease gun.

Thirdly, if one went bad, you need to replace the entire driveshaft from what I've been told and researched. Because I wanted to get Zerked Spicer u-joints, but no one had any of any brand.

 

sorry if it was confusing, but it's this thing that actually slides in and out of the transmission that i believe is connected to the output shaft via splines.



ive been told that if those splines lack lubrication it could cause clunking when it loses load such as pressing on the clutch.

 

I think that the guy who told you that it is lubricated by the transmission fluid was correct. That's the same design that the old rear wheel drive cars had, and they didn't have to be lubricated. I think the slip yoke you are referring to is the external part of the 2 piece driveshafts, where the two come together, used on many trucks.

 

That is a trans slip yoke and not a flange. It is lubed by the ATF but a common fix is to put a good moly type grease inside the slip - not too much - it may fix the clunk. Also a 12mm 12 point wrench will remove the bolts and u-joints with zerk are easily available at any parts store.

Hope this helps,

Thanks & Have a Great Day,

Arlene - PST, Inc.

 

Now I'm no expert, just a block one technician... I get involeved in forums just as much to learn as I do to give advice. If that slip yoke is causing the clunk, that would mean that either the splines in the driveshaft end, or tranny end, or both are wore. Correct? So moly grease would just eliminate the clunk, not the play wouldn't it?

Secondly, just out of curiousity... when ur driving along under low load (rpm's low) and then plank it (mash the pedal to the floor), does it ever clunk then?

 

if the yoke isnt getting lubricated perhaps your tranny fluid is low. check its level.

 

hi guys and thanks for the responses.

i, in fact, changed the fluid but that didnt help. i also thought that it might have been low, but it was indeed at a perfect level. there's no leaks around as well. also replaced the stock u-joints w/ dana spicers, but that didnt solve it either.

the clunk only happens from 1st to 2nd and 2nd to 3rd esp in a stop-and-go traffic where most of the time the tranny is in 1st/2nd gear. from neutral (dead-stop) to 1st, if i ease it in, there's no sound at all. when i do it "quick", a "thud" or clunk is present. when i accelerate from 1st and change to 2nd or back to neutral, upon pressing the clutch, there is a clunk present 90% of the time. i can say the same about acceleration from 2nd to 3rd or back to neutral. low or high rpm doesnt seem to make a difference for these scenarios. all other gear change does not produce a clunk. pressing the gas after a gear change also creates a clunk which seems to be coming from the rear-end (ring & pinion backlash).

i dont know if these could all be related to the differential gear change i had done recently, but these indeed seem to be more evident now than then if these were all in fact present before. i already had the local shop who did the job check the specs and all are within range.

also, i dont know if it makes a difference, but with the vehicle parked and in OFF state, i attempt to simulate the clunk, but there's no clunk at all with any of the gears. pressing the clutch and releasing produces no noise. changing gears produces no noise.

i really want to bring it in to a shop, but i dont have funds yet. any other inputs appreciated!

 

Sounds more like differential noises to me.

 

agreed, sounds like the differential needs to be re-shimmed

Set the parking brake all the way to the floor, put your truck in N, climb under the truck and try and spin the driveshaft back and forth. If you have more then about 20* of play it needs some work done on the rear end.

manual, you can get U joints for the 04-08 trucks. We did a set on Edwards truck (Etrevino13986) or whatever his numbers are after his name

 

Put the grease in the slip yoke as was suggested. If the clunk is from the slip yoke this will eliminate it. But...... was there a clunk before the new gears? No clunk would be faulty install of the gears. There is one fundimental difference between a manual tranny and an automatic. When you let off the gas you unload the gears as does an automatic. But with a clutch, when accelerate, you take up the slack with no cushioning that a torque converter affords. So any clunk noise will be amplified. Over time this will get worse. If the gears were not set up tight enough then they will clunk.

 

thanks again for the responses.

to be honest, i dont think the clunking was there before the gear change, although, it could be the fact that after being paranoid of trying to listen to "noises" after a gear change that only then that i started to hear all of these. radio used to pretty much overlap any noise that i may never really have heard of per say. however, the clunk is pretty evident even with the radio audio level up there now.

i understand the difference between manual and auto, but how much "clunking" is considered normal.

Patman - how do i measure the degree with the driveshaft?

JMC - how tight is tight enough?

im assuming these mainly refer to backlash and maybe carrier pre-load? ill see if i can try and grease the tranny slip yoke.

 

Tight enough would be setting the tolerances to the minimum not the max.


Regards


Jean Marc Chartier

 

ATF can be fed to the tail shaft from the test port.

 

Only works with an automatic 4x2. M5OD Manual Trannies do not use a pump and the BW T-case has no access to the pump output without some tinkering inside the case.


Regards

Jean Marc Chartier