2003 4 x 4 FX4 4.0

Still trying to track down a vibration, and want to eliminate the rear drive shaft as a possibility.

The question nobody wants to answer is will the transfer case have a problem if I pull the rear drive shaft and run it at highway speeds for a bit running in 4H with only the front shaft in place?

Did the a whole winter in my old '46 International, but things were made a WHOLE lot heavier back then

 

I did this with my 89 Ranger and it did OK. I did it because a U-joint was going out in the rear driveshaft and I needed to get it home. I accelerated moderately so as not to stress the front drive. It seemed to have a lot of backlash in it but that may have been due to the auto locking hubs.

 

+1, yes you can

 

By backlash I'm assuming you mean the hop when turning?

 

I think he means the chain, BW1354 uses a chain to drive front end

Rear axle is direct drive, input shaft to output shaft, it has the hi and low gears but still direct

Front drive shaft uses a chain drive so can have a bit of slop, you won't feel it with rear axle also driving vehicle, but can with just the front drive working

 

I don't know what causes the backlash but I do mean there was slop or play in the front drivetrain with the rear driveshaft out. When I let up on it I could feel free play and then again when I would accelerate. The chain drive could be the cause and the auto locking hubs may have contributed also. Easy transitioning when decelerating and accelerating minimizes the jerkiness.

 

You know, I have another post, 'double clunk'. I didn't realize that the front shaft was chain driven. I'm wondering if the 'double clunk' I hear when pulling away from a stop might be the chain taking up that little bit of slack? Would it still make the noise in 2H?

 

Okay, I TRIED to remove the rear drive shaft. Evidently the transmission shop that did the rebuild thought it appropriate to crank the bolts down so far I can't break them loose. I had my 12mm wrench and an 18mm in the open end for torque and still couldn't get it to pop loose.

On a better note, I think I may have found my high speed vibration. In taking a crack at the front bolts I put my hand on the drive shaft to brace... and it moved!

The expansion joint under the bellows has visible movement in all directions. As this is a slide joint my thinking is it shouldn't have ANY lateral movement. It is more movement than I would accept from any u-joint, and enough that I would want to replace it if it was a u-joint.

Am I barking up the wrong tree?

 

Slip yoke can cause clunk noise

Article here on re-greasing it: TRS Magazine - Fixing A Driveshaft Clunk

 

Understand the yoke noise. What I was talking about on the double clunk post is something I've never heard from a vehicle before, and not something I would expect for a gear driven front axle.

When I put it in gear I get the usual clunk I would expect for an older drive train to take up the slack. But then I get a second clunk just as I move forward. I had assumed I had something going on, but knowing the front output from the transfer case is chain driven would explain the second clunk as the front half of the drive chain takes up it's slack as well.

As for the play in the slip yoke, this drive shaft is not the old fashioned front spline to the transfer case and U-bolt to the rear pinion type. It has a flange on both ends with a short slip near the front yoke with rubber bellows over it. It has crimped bands holding the bellows in place and I don't want to start digging into it not knowing what I'll find. Especially when the rubber bellows appear to be in good shape, no sign of cracks or even checking of the rubber.

That being said there is the significant lateral movement in that slip joint. Enough that I would not accept that much in either of the U-joints if it had that much play.

This made an appearance after having a shop work on the fuel tank, they had to drop the shaft to get to the fuel tank. I'm not trying to throw blame, it could be that it had been undisturbed for many years and the simple act of removing the shaft and it getting more travel than it was used to upset something.

If somebody knows different about those slip joints I would love to hear from them.

 

I am pretty sure the chain should not be turning when in 2WD. The front shaft is still turning but the transfer case disconnect should keep the chain from turning.

That driveshaft slip joint is notorious for drying out and causing a clunk. Around a 100 K miles ago, I took mine apart and lubed it up very well and put it back together. No more clunk and it is working very well at over 220K miles. I was able to reuse the bands that hold the rubber bellows in place. Some people use sturdy tie straps instead. When I relubed it, it seemed to tighten up a little. If it is really loose you may have to do something about it. Powertrain shops can rebuild it but by the time they do that and rebalance, it may be better to spend a few bucks more and buy a new drive shaft.

 

Not sure what you can do to 'rebuild' a slip spline connection. And this is WAY beyond what lubing would take care of. In some ways I'm glad this is part of the drive shaft and not half and half between the transfer case and drive shaft. My luck it wold be the transfer case half that was worn and require tearing it apart.

As you said, the cost of rebuild and repair MUCH out weighs the cost of replacement. Might even see about steel instead of aluminum. When I called a salvage yard they asked aluminum or steel so it might be an option.

 

Okay, picked up a used drive shaft from the salvage yard, and was going to lube it before I put it in place.

Stopped at two local parts stores, NAPA and Bumper to Bumper, and neither one had ever heard of a Teflon based lube.

Is this a Ford specific lube? Is there a suitable substitute?

 

Just a thought, but shaft drive motorcycles almost always use a high molybdenum content lube (Honda Moly 77, etc) for the splines. It would be more expensive, but a tube of it would probably last you forever.

 

One of the posts I saw said Teflon ( PTFE ) as a first choice, and Molly as a second so that makes sense. Fun part is neither parts store has either one. And get this, my little Ford dealership had to go look it up and would have to order the PTFE in. Like their guys never lube a drive shaft!