Front Drive Shaft (4406) question

[Turdle]

Hi, thanks for reading.

When I had the Black Mountaineer I stuck a 4406 transfer case in.

[MENTION=45215]MountaineerGreen[/MENTION] then sent me a PM "I have the front drive shaft you need" and i said "ok" so he sent it to me. I stuck it in and that was that. It worked smooth as silk.

Forward a little time, we talked about the fact he wanted to remove his superlift suspension lift, so I went to his place where we swapped it over to my black mountaineer.

So, because the front diff was dropped 4 inches we also needed to swap front drive shafts. This time I got a double cardan to help with the increased angle.


Fast forward to present Truck, 2000 mountaineer.

I have been experiencing a vibration. Bad enough to rob fuel economy.

Yesterday I removed the front drive shaft and the truck drove smooth. After 2 round trips to the next town south fuel economy increased.

With the drive shaft in place we also experience a popping, thud noise in 4 wheel drive, which was never experienced with the black truck. So, for this truck I have tried a different front diff, and cv's with no change.

I suspect my issue is the fact I have a double cardan drive shaft with a slip yoke and no suspension lift. There is not enough angle to justify it being there, and, without the increased angle on it it is trying to "twist itself up" in 4wd mode. I think the slip yoke also plays a part in this

I would like to try the single u joint drive shaft again. I hope Evan will chime in with ideas.

I do have 3 new u joints and a double cardan rebuild kit, however I think what I really need is a fixed length drive shaft with single u joints.

Help?

 

[MountaineerGreen]

After we took the lift off my Mountaineer, it drove fine using a standard driveshaft up until the time it hit the tree. I certainly don't think the double would cause you problems unless the u joints are worn. The clunk you mention when in 4x4 sounds like your joints may be worn. Has it always have a vibration or has it only recently begun?

I looked back at my thread from the conversion http://www.explorerforum.com/forums/showthread.php?t=166726 An expedition driveshaft ought to be readily available, those vehicles are old enough now if you wanted to switch back. If you have the parts and the time, I'd be inclined to replace those u joints if you haven't had vibrations in the past.

Holy cow, that conversion thread is 8 years old!!!

 

[Turdle]

Yeah, that is part of the problem. Years and memory don't always work together.

I want to try the expedition shaft, I think. Thanks for your input Evan!

 

[Turdle]

I am overwhelmed by the responses here.

Hmm, maybe I should clarify my question.

Since my truck has no suspension lift, and a fixed front differential why do I need a double cardan drive shaft? The expedition shaft I had on the Turdle before it was lifted was smooth.

I think the double cardan being so straight is causing this

Yes video is "upside down". Watch for the jumping thumping differential. Just keep you eye on the bottom left corner of video and you will see--hear it.
I believe this is the double cardan "twisting up" due to lack of angle and slip yoke slack.



you will see it at :46 and :59

I have been told this is normal due to "turning" however the black truck did not do this. Ever. And it had a rear locker.

I have also tried new cv axles and a complete different front differential. Still thumps.

 

[MountaineerGreen]

I can't see how the double cardian will twist or bind. I always thought up to a point, more joints made for a smoother transition. But, I'm not an engineer either. An expedition driveshaft is tested and proven, just make sure you don't get one that is too long. There was a length issue depending on engine, iirc.

 

[delexploder]

I said that about the front diff last time you posted a vid like that, that's not normal,

 

[vroomzoomboom]

i've had a vibration in mine from the day i put the 4406 in. a single joint or double didnt solve it. it drive me nuts because if i go on a long trip, or do over 55-60, i have to pull the front shaft out.
when i helped [MENTION=102869]Dono[/MENTION] do his swap, we used the double i had (and not may miles on it either). took it for a run down the highway, and you could put a glass of water on the dash, and wouldnt get a ripple from it. its also funny because [MENTION=119708]ahodges[/MENTION] and i where talking about this same thing last night, and [MENTION=43652]joshuaj0214[/MENTION] and i a week or two before that. IIR, josh said when he did his swap, everything was fine until he beat on it a little bit, and now he to has a vibration. i wounder if we all have bad diff bushings? just throwing that out.

 

[ahodges]

That thumping looks to be something a little different and even more puzzling. Here is my experience with double cardens and single u-joints. A U-joint needs a minimum of 2 degrees angle for the needle bearings to be properly lubricated. Street applications I have been told that you want between 4 and 6 degrees angle difference on a U-joint at the differential for it to perform properly. With that being said, a double can't be used unless there is at least 4 degrees difference and isn't needed until there is more than 6 degrees angle difference (that makes sense right?). Now I originally had a double in the rear and front drive shafts right off of both ends of the transfercase. Within the last week I had a new rear shaft made with a single U-joint on each end. I have ~4 degrees on each U-joint on the rear shaft. I still have a slight vibration that comes in around 65mph, most noticeable at ~70mph and by the time I'm going 80 I don't notice it (with the FRONT DRIVE SHAFT REMOVED). The vibration is noticed during acceleration and constant cruising; when costing it disappears. With the front drive shaft in the vibration is even more noticeable. I think that is due to the harmonics being transferred forward.

I am going to re-check the run-out on my rear shaft tonight maybe. I haven't figured out a good way to mount my dial indicator so that the suspension travel doesn't give me false readings.

I don't think it could be the bearings in the front axle because I just had mine rebuilt with all new bearings and I am still having the same issue. If everyone's rear drive shaft is indeed built correctly and balanced correctly then I am baffled why we still have problems even though the front drive shaft is removed.

 

[vroomzoomboom]

hurt, help, or not even useful to this thread but i forgot i had this bookmarked.

http://www.explorerforum.com/forums/showpost.php?p=1950202&postcount=274

 

[Turdle]

hurt, help, or not even useful to this thread but i forgot i had this bookmarked.

http://www.explorerforum.com/forums/showpost.php?p=1950202&postcount=274

Yes Tim, he had a superlift which drops the front diff 4". That is why he needed the double cardan.

I can't see how the double cardian will twist or bind. I always thought up to a point, more joints made for a smoother transition. But, I'm not an engineer either. An expedition driveshaft is tested and proven, just make sure you don't get one that is too long. There was a length issue depending on engine, iirc.

I thought so to-

all was smooth with the black truck. No lift, no double cardan, and with the lift it had a double cardan. I drove it to Colorado and back both ways-

The only difference on this one is the double cardan without a suspension lift. Ahodges hit it on the head. The double cardan is not "working" enough IMO. There is not enough angle for the u joints to operate correctly.

Think of it like this. Stick 2 socket set u joints back to back. Now put an extension on each end of that. You now have a rough example of a double cardan . Put some angle on it and it will work well. Now try with it straight.

Twist it at one end and hold the other stationary. If, and only if you can keep the length it will not twist up. but it will twist up easily,
I think my drive shaft is doing this because the slip yoke doesn't hold the length, and, the double cardan is wanting to get angled, or, twist up. . Remember-the stock awd front shaft is a fixed length, for the most part. There is a slight amount of give but not much. Just because the transfer case changed doesn't change the fact the front shaft should be fixed length. It doesn't move around like it would in a TTB or Solid front axle setup.



Maybe I am nuts but that is what it feels like is happening. You'd have to feel it yourself.







As soon as I can acquire a single joint front drive shaft I will let you know.

 

[vroomzoomboom]

ah ok. i thought the link i posted was for non lifted trucks. i know the thread that evan made years ago was for lifted trucks. i know when i did mine 2 years ago, i had to get it shorten.
my bad!

 

[ahodges]

Sounds good Jon. Sounds like we may be making progress on this. Many may not know but I introduced another variable to the drive shaft equation, I installed a Ford 9" with the yoke style pinion in put. I did some research yesterday and realized that I probably over torqued the bolts that hold the rear u-joint to the pinion. I took it apart rolled the u-joint caps around and just snugged them up. Vibration [B]without[/B] the front drive shaft in - solved.

I put the front shaft back in and it has an ever so slight vibration between 68 & 73ish. I am using the double carden front shaft that is stock to 91 - 96 explorers that Tim posted a link too. Common thing I see is that everyone refers to the double carden shaft as what was used in the 1st gens and that isn't completely true. They also used it in 95 & 96 with the disconnect front carrier. Anyhow, I noticed that when I engage 4wd, the vibration completely disappears at all speeds - figure that one out. I am going to play with modifying the pinion angle of the front carrier some more to see if it helps. Something I have noticed in all of my measuring is that there is almost no angle at all on the u-joint that connects to the front carrier, using the stock mounting angle. I am working on angling the pinion either up or down to give it at least 2 degrees angle, 4 might be better. The way I had it when testing last night was 2 degrees nose up, which seems like it would be right because the front pinion wants to torque down when power is applied, correct??

I'll wait to see Jon's results before I go single u-joints on the front shaft too.. In the mean time I'm going to keep messing with this double and do more measuring/ angle finding.

 

[masospaghetti]

I might be misunderstanding because I can't see the pictures - but - the stock shaft had a single cardan on the differential side, and either a double cardan or CV on the transfer case side.

The geometry is wrong to use two single cardans. I haven't tried it (and amazingly, the parts houses sell this kind of shaft), but it seems guaranteed to be vibration hell.

If the stock geometry used a double cardan and a slip yoke I don't see why yours would be an issue. I recently installed a double cardan shaft on my 96 Ex and its smooth.

 

[masospaghetti]

Something I have noticed in all of my measuring is that there is almost no angle at all on the u-joint that connects to the front carrier, using the stock mounting angle. I am working on angling the pinion either up or down to give it at least 2 degrees angle, 4 might be better. The way I had it when testing last night was 2 degrees nose up, which seems like it would be right because the front pinion wants to torque down when power is applied, correct??

Unlike a normal prop shaft that uses two single cardan joints on either end that effectively cancel each other out, the shaft you are using only has a single cardan on one side, so any change in shaft velocity will be felt as vibration.

That being said, a very small angle is needed to keep the needles moving inside the u-joint and would be so minimal it wouldn't be felt. Personally, I think increasing the angle to 2 or 4 degrees would only make the issue worse. I also don't think you'll see the front diff move much when power is applied because its mounted pretty rigidly to the front suspension, unlike a rear end that is suspended only by leaf springs and can more easily rotate.

 

[MountaineerGreen]

Yes Tim, he had a superlift which drops the front diff 4". That is why he needed the double cardan.


I thought so to-

all was smooth with the black truck. No lift, no double cardan, and with the lift it had a double cardan. I drove it to Colorado and back both ways-

The only difference on this one is the double cardan without a suspension lift. Ahodges hit it on the head. The double cardan is not "working" enough IMO. There is not enough angle for the u joints to operate correctly.

Think of it like this. Stick 2 socket set u joints back to back. Now put an extension on each end of that. You now have a rough example of a double cardan . Put some angle on it and it will work well. Now try with it straight.

Twist it at one end and hold the other stationary. If, and only if you can keep the length it will not twist up. but it will twist up easily,
I think my drive shaft is doing this because the slip yoke doesn't hold the length, and, the double cardan is wanting to get angled, or, twist up. . Remember-the stock awd front shaft is a fixed length, for the most part. There is a slight amount of give but not much. Just because the transfer case changed doesn't change the fact the front shaft should be fixed length. It doesn't move around like it would in a TTB or Solid front axle setup.



Maybe I am nuts but that is what it feels like is happening. You'd have to feel it yourself.







As soon as I can acquire a single joint front drive shaft I will let you know.

I think you may be on to something. The reduced angle could cause pre mature joint wear and the length adjustable shaft could magnify that effect. There were some factors there I hadn't considered. I haven't crawled under an explorer / mountaineer in years, I'm getting out of practice. I bet a regular drive shaft will cure your ills. Some of the old Jeep Cherokee driveshafts may work for you too, they won't require a conversion joint, if you can find one without a DC.

 

[Turdle]

I got a used f150drive shaft, and new u joints.
I went ahead and ordered the brute force conversion u joint which will allow me to use the longer f150 slip yoke, if it proves too long I have a new u joint for my present slip yoke also.

 

[delexploder]

Hey Jon, I messed with my front shaft yesterday and got it to collapse as far as it will go but its still too long by maybe an inch, if I can get the slip yoke off and the cap off the female side without breaking anything im gonna do some trimming,

 

[Turdle]

Hey Jon, I messed with my front shaft yesterday and got it to collapse as far as it will go but its still too long by maybe an inch, if I can get the slip yoke off and the cap off the female side without breaking anything im gonna do some trimming,

I noticed the slip yoke I have on the DC shaft is about 1.5" shorter then the f150 slip yoke.

 

[delexploder]

Maybe I have a year combo issue,

 

[Turdle]

How long is yours compressed? I will measure mine-


Measure to the front u joint, the flange ( mine came with a front flange) is not needed.