Driveshaft Replacement

[Elroy]

Has anyone replaced a driveshaft? A member of my club has a cracked U-joint and the only way to fix it is to replace the whole shaft. So he ordered a new driveshaft that should arrive tomorrow, and we're looking for a few tips from people that may have already conquered this task.

TIA

[Toy Man]

Too late now but I understand you can use u-joints from a Frontier for the Xterra.

Toy Man

[OffroadX]

No biggie if it's a 4x4 (no carrier bearing). Start by parking with the nose downhill or the rear up on ramps. This will minimize or eliminate fluid loss from the transfer case when the slip yoke is pulled out, but be ready for some spillage just in case. Of course, block the wheels for safety!
Make a mark on the diff input flange to note the orientation of the u-joint so that you are sure to put the new one on in the same orientation. The "shoulders" of the flange end of shaft that support the u-joint should not be 90 degrees off from before in relation to the diff flange afterwards.
Then it's just a matter of undoing the 4 bolts holding the shaft to the diff flange and the driveshaft will just pull out of the transfer case. Slide the new shaft in being sure to keep the same orientation at the flange and bolt it back together to 65 ft-lbs. According to the ESM, the bolts, washers, and nuts are NOT to be re-used, though I can't really imagine why not.

Brent

[Olegkha]

there is no fluid lost even if the truck is level ones you pull out the drive shaft from the transfer case

there is no need to mark anything on the case, there is only 1 way to put everything back together, ( just dont move the truck with the drive shaft not attached )

you will need something to press out the U joint

[OffroadX]

Oleg, it IS possible to have the shaft out of sync with the flange, and you SHOULD ensure that the correct orientation is maintained. Why is this made clear in the service manual if it's not important? I suspect you will end up with vibration if it is not re-assembled correctly. It's certainly not difficult to do and there's no reason to disregard this simple step.

Brent

[Olegkha]

Brent , there is only one way to put it back on, and if the tires have not been moved then you are ok, if the tires were moved, then it will be wrong

I set parking brake on, when my drive shaft was removed, to prevent tires from moving

[OffroadX]

So you're saying you can't unbolt the flange, pull the shaft out of the t-case, rotate it 90 degrees, slide it back in, and re-bolt it to the flange? Of course you can, the slip yoke has splines and the shaft can go into the t-case in quite a few different orientations, but only 4 of them will actually allow the flange bolts to line up again, and only 2 of those will keep the same phase.

Brent

[Olegkha]

as loong as the tranny and the diff are left in the same position, it dont matter how you install the drive shaft
(as loong as the gears of the transfer case and the the gears in the rear diff are left in the same place, they should be in phase )


drive shaft WAS balanced when it was created ( i had couple of weights glued to it ) so no matter how you install it it will still be as balanced as it was


If you do move the wheels, that will move the gears in the rear diff, that will bring diff gears and tranny gears OUT of phase, and that COULD create some problems ( or vibrations as you sad )

[OffroadX]

Oleg, there is absolutely no relationship between the t-case gears and tranny gears, nor could one be made. You can pull the driveshaft and spin the rear tires around randomly and it wouldn't matter one bit where they ended up. The only relationship that matters is the one between the driveshaft and the pinion flange.

[Olegkha]

yes there is

if nothing moves then everything will go back in exact same position as it came out

Brent have you changed the drive shaft ? ( OR ARE YOU JUST LOOKING AT PICTURES ? ) or have you atleast taken one out ?
I think the answer for that question is no , so how can you be so sure ?

have a good weekened

[Elroy]

Thanks guys. A lot of this conversation has helped, but some of it has also confused me. I guess we'll see when we get to it Friday. I also have the Electronic Service Manual I can consult.

Thanks again.

[OffroadX]

Sorry if it's confusing, but it really boils down to the fact that it doesn't matter if I'm right of if he's right, you can't go wrong by marking the orientation of the flanges and putting the new one back in the same way.

Good luck,
Brent

[warmonger]

Guys,

I don't give a flying #$%^ what the service manual says, a drive shaft is balanced for CENTRIFIGAL force. That means that no matter its position on the output shaft at the transfer case it will maintain balance. There is no keying or anything of that nature. It IS wise to go ahead and mark it just to be on the safe side as OffroadX said, but it is not mandatory on a centrifgally balanced shaft. That is like saying that the l/f tire won't go on the r/r without throwing the whole truck out of balance. As long as the tires are centrifigally balanced, their location doesn't matter unless they are directional treads!

[Elroy]

Thanks a lot guys for all of your help. This was one of the easiest things I've ever done to the X. It's almost easier than changing wiper blades.

We jacked up the rear of the vehicle and put it up on jack stands. Marked the diff input flange, then removed the 4 boths. After removing the bolts, the drive shaft just slid out. When the part that was in the transfer case slid out, it tilted down and leaked fluid. That was the only fluid loss we encountered. We put the old one aside, then put in the new one. Very easy.

When we thoughly inspected the old one, we could tell that there was no way we could have just replaced a U-joint. The part that was bad (cracked) was welded to the drive shaft.