4x4 truck shakes

Zaggnutt · Feb 24, 2015

I have researched this problem, but I have a couple hang-ups. Shifts into 4x4 fine not bound up. When I attempt to drive with it in 4x4 the truck shakes really, really bad. So I unlock the hubs. I got under the truck with the hubs unlocked and rotated the front driveshaft to check for play, bad u joints, leaks, etc. I noticed fluid on the t-case, but I'm not sure exactly where it's coming from yet. joints seem good.

I can rotate the driveshaft 360, but at about 180 it gets harder to rotate. It spins smoothly, but with more effort (I have to use two hands). Once I hit about 360 it is easy again for about half the turn and same thing happens. No scrape or grind feel or noise.

So I am looking and listening and what I noticed was that the front axle and the transfer case flex when I hit the "tough" part of the rotation. I can see the bottom of the axle diff. housing and the transfer case flex as in push away from the driveshaft. It isn't much obviously but enough for me to say "***?" I don't know much about the TTB and I'm hoping I don't have to tear apart the whole axle to get at the gears but if so I am looking for some trouble shooting advice AND some instruction on how the hell to get at the front axle efficiently. I will get a video tomorrow if I can. Thanks!

IDIoit · Feb 24, 2015

disconnect the driveshaft from the front axle to isolate it.
im not sure whats flexing from your description.

Zaggnutt · Feb 24, 2015

IDIoit said:
disconnect the driveshaft from the front axle to isolate it.
im not sure whats flexing from your description.

Sorry, it's hard to explain. That's why I mentioned taking a video of it tomorrow. If I'm laying under the 4x4 driveshaft and looking at the back of the front axle I can see the axle housing move when I rotate the driveshaft. The housing pushes away from the driveshaft in correlation to the increased resistance of the driveshaft.... Okay, okay, okay.... Imagine that when the driveshaft gets more difficult to rotate that it is getting longer and pushing the t-case and front axle housing away from it. Just for the sake of picturing the movement I am describing. Does that make sense?

My terminology is wrong here. By "axle housing" I mean "Carrier". Sorry bout that.

Zaggnutt · Feb 24, 2015

I searched forums and youtube for insight but I'm not finding anything like this. I was also hoping to find someone who did a step by step on dismantling their 44 but I can't find that either. Everyone either has the whole axle out already or they have the carrier sitting on their workbench.

IDIoit · Feb 24, 2015

im assuming your talking about the front driveshaft.
these are adjustable a little bit.
i would still pull the front driveshadt completely out and check it out then.
is it the transfer, is it the front end, is it the driveshaft?
usually if you take it off real quick, the problem presents itself.

Zaggnutt · Feb 24, 2015

IDIoit said:
im assuming your talking about the front driveshaft.
these are adjustable a little bit.
i would still pull the front driveshadt completely out and check it out then.
is it the transfer, is it the front end, is it the driveshaft?
usually if you take it off real quick, the problem presents itself.

Okay, will do. Yeah, I mean the driveshaft that connects the transfer case to the front axle. That is the one I am spinning. 4x4 troublshooting 101. 1, Spin 4x4 driveshaft. Does it spin freely? Good. 2. Lock hubs. Spin driveshaft. Does it spin? Not good. 3. etc. etc. LOL

.

LCAM-01XA · Feb 24, 2015

Zaggnutt said:
Okay, will do. Yeah, I mean the driveshaft that connects the transfer case to the front axle. That is the one I am spinning. 4x4 troublshooting 101. 1, Spin 4x4 driveshaft. Does it spin freely? Good. 2. Lock hubs. Spin driveshaft. Does it spin? Not good. 3. etc. etc. .

That's pretty much only telling you if the front hubs are locking, not much else. What you describe sure sounds like a driveshaft U-joint binding, the only way to check for sure is to pull the shaft and try rotating the joints across their travel by hand. Checking them with the shaft in place will tell you if they're loose, which your problem seems to be the opposite. Also while the haft is out you can turn both the t-case yoke and that at the axle by hand, if there's something binding in either you will feel it easy enough.

As for the axle and t-case flexing I kinda get what you're trying to say, but I'm surprised you can see anything at the axle as that is under the weight of the truck so it shouldn't move at all while the wheels are on the ground. T-case shouldn't be doing it either, but it has a single mount there under the transmission so it is more likely to move under load. But yeah, pretty positive your problem is a driveshaft u-joint fixing to freeze up on ya.

Zaggnutt · Feb 24, 2015

LCAM-01XA said:
As for the axle and t-case flexing I kinda get what you're trying to say, but I'm surprised you can see anything at the axle as that is under the weight of the truck so it shouldn't move at all while the wheels are on the ground.

Yeah, that's what I was thinking hence the "***?" response I had when I saw it. I will get that shaft pulled off and post results. Thanks LCAM. You've been around, huh? You always got an answer. You know if "my very own hell" was down the street I'd be camped out at your house on the weekends lookin' for help workin' on my trucks

LCAM-01XA · Feb 25, 2015

Yeah, if you were down the street you wouldn't be camped out at my house, I'd be taking refuge at yours... Too bad it wouldn't take very long at all for my very own hell on heels to figure it out and enslave us both for working on her projects LOL

As for having been around, idk about that, but considering we got a truck for each family member (including the one who doesn't drive yet) plus a few extras, well, I guess some things come with the territory

Back on topic, if you lay under your truck and try to bench-press the end of the transfer case that the front shaft comes out of, you will notice some movement in the up direction - not a whole lot, but it will be there. Thing to check is are the bolts holding the t-case to the transmission all tight? Granted, the t-case has a ring machined into its face to keep it coaxial with the transmission, and a locating dowel to index it, and they all fit pretty darn tight, but still, worth taking a look just in case. The front axle however should not be moving at all, the differential housing is so stupid-heavy on its own that even if its bolts were loose as heck it still shouldn't budge just from you turning the shaft by hand. You may have some serious play in the pinion bearings though, that could allow the yoke to flop around some. It's a common issue with the Sterling rear axles cause they use a crush sleeve, however the Danas use solid shims and the pinion nut gets some really high torque, so unless the bearings are very shot it shouldn't develop any play on its own like the Sterlings do. But you'll be able to check for that once the shaft is off. Same thing applies to the t-case yoke as well, well to a lesser extend as that only gets ball bearings or straight roller bearings, not preloaded tapered ones like the pinion, but there should still be no slop in it when you try moving it around once the shaft is out of the way.

Zaggnutt · Feb 25, 2015

LCAM-01XA said:
Yeah, if you were down the street you wouldn't be camped out at my house, I'd be taking refuge at yours... Too bad it wouldn't take very long at all for my very own hell on heels to figure it out and enslave us both for working on her projects As for having been around, idk about that, but considering we got a truck for each family member (including the one who doesn't drive yet) plus a few extras, well, I guess some things come with the territory

Back on topic, if you lay under your truck and try to bench-press the end of the transfer case that the front shaft comes out of, you will notice some movement in the up direction - not a whole lot, but it will be there. Thing to check is are the bolts holding the t-case to the transmission all tight? Granted, the t-case has a ring machined into its face to keep it coaxial with the transmission, and a locating dowel to index it, and they all fit pretty darn tight, but still, worth taking a look just in case. The front axle however should not be moving at all, the differential housing is so stupid-heavy on its own that even if its bolts were loose as heck it still shouldn't budge just from you turning the shaft by hand. You may have some serious play in the pinion bearings though, that could allow the yoke to flop around some. It's a common issue with the Sterling rear axles cause they use a crush sleeve, however the Danas use solid shims and the pinion nut gets some really high torque, so unless the bearings are very shot it shouldn't develop any play on its own like the Sterlings do. But you'll be able to check for that once the shaft is off. Same thing applies to the t-case yoke as well, well to a lesser extend as that only gets ball bearings or straight roller bearings, not preloaded tapered ones like the pinion, but there should still be no slop in it when you try moving it around once the shaft is out of the way.

Copy that. Yeah, you could take refuge here.... No women around except my girls and they're only here every other weekend and the weekdays. Thanks for the advice. Not sure what's going on in the front, but I will start inspection tomorrow. Lawn and landscape seminar today.

FarmerFrank · Feb 25, 2015

... Does the drive shaft have a slight bend or bow in it?? That would make it hard to turn half way around and might not be letting the slip joint move.

When you pull it try rolling it and see what it does.

Zaggnutt · Feb 25, 2015

FarmerFrank said:
... Does the drive shaft have a slight bend or bow in it?? That would make it hard to turn half way around and might not be letting the slip joint move.

When you pull it try rolling it and see what it does.

didnt think of that. Will check that out too. Thanks!

Zaggnutt · Feb 28, 2015

Okay, on Farmer Frank's advice I tried shifting into 4HI with hubs UNLOCKED.... Got the shakes (no, not because I needed a drink) rotated from underneath again, but can't see any noticeable damage or even a bend. Didn't have time to remove it. Final diagnosis is: Bent front driveshaft. Ugh. Okay, so here's my Noob tip for the day: When test driving a truck for possible purchase and asking about the 4x4, do not rely on the P.O.s response "It worked last time I checked it." I shifted through 4Hi to 4Lo and it was smooth but didn't drive it engaged because we were in town and there was no mud or snow around. This is the second P.O. that gave me that line, but the first one I fixed with a fabbed shifter link.

Zaggnutt · Feb 28, 2015

Yeah, yeah, yeah, I know. Fool me once blah, blah, blah.

dunk · Feb 28, 2015

I'd think if it was bent enough to shake it would be visible. You have removed the shaft and ujoints move freely and needles intact? Mine has bad ujoints in front and causes some vibration from being still through part of the rotation. If I didn't have another truck for when I needed 4x4 I'd have fixed it by now, just 8 nuts and two ujoints I'm sure I have on the ujoint shelf. Too cold and too lazy since it's not my only option but it's good enough for the times I've had to use it, I'll wait for an above freezing day to do it particularly since when I do stuff like that I prefer to strip rust and paint fresh. Bigger issue is I need to do axle shaft ujoints and don't want to pull them in the cold.

4x4 truck shakes

Zaggnutt

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