Help with 2 piece driveshaft alignment.

Mac5005

Mac5005

Well-Known Member
Joined
Oct 19, 2005
Location
Rocky Mount
I picked up a new DD/tow pig, and yesterday/today I’m going thru changing all fluids and filters, overall prep for a new to me truck.

08 2500HD CCLB.

Noticed something odd on the rear driveshaft and wanted to ask here.

I’ll update in a few with pics and definitive angles and such.

Truck has a 2 piece rear driveshaft, with center bearing.

I was checking the phasing of the u joints, as it looks like someone replaced that center bearing somewhat recently.

Working from the tcase u joint towards the rear, the first and second u joints appear to be slightly out of phase.

Between these joints is the slip joint, and center support bearing.

I’m wondering if it was reassembled with the phasing slightly off, or if this was intentional.

Appears to have a scratch mark on each side of the slip, which I’m assuming someone marked the phasing before changing the center support bearing.

The marks line up, but if I put a straight edge along u joints, they aren’t phased exactly correctly.

Other issue is that the center support bearing has a stamp marker FRT with an arrow. I would assume this means to point the arrow towards the front of the truck, but this one is installed to point towards the rear.

Is this enough worry to pull the center support bearing off and flip it, so the FRT and arrow point towards the front of the truck.

While messing with this, I’m going to check angles of it all to see if the center support bearing needs to be shimmed.

Pics when I get back to the shop.
 


That video helped me out a ton phaseing the two piece driveshaft on my Tacoma. It went from some pretty crazy driveline vibrations to pretty much zero. That method is so much easier than trying to eyeball it, line up marks and all that other stuff. My Tacoma has an un shimmed center bearing and the rear diff is offset 3" to the right for reference.

I would focus on getting the angles dead nuts on before flipping and shimming center bearings.
 
I just had the local powertrain shop install new Spicer u-joints, center bearing (that I brought), and balance my driveshaft for about $250. It's amazing how smooth it is now and the vibrating steering wheel is gone.
 
10° difference in phase from the front portion of the mid shaft to the rear portion of the mid shaft.

If the midshaft slip joint is 36 spline, then I would assume it was assembled one spline off. Going to have to pull the driveline to remove center support and get that slip joint apart, to see if moving 1 tooth, or 18 teeth net better alignment.

Cant find any information anywhere about allowable angle in phase, or spline count of that slip joint. It’s covered with a rubber dust boot, so counting splines is impossible before disassembly.

Total working angles are correct with the mid shaft parallel to the rear pinion. So no shimming of center support bearing is needed.

Ignore after the decimal point with the angle finder.

Also included pics for filling diffs with gear oil when it’s cold.

54E87EB1-4AD0-4578-B59C-E8CA7DE90D0F.jpeg
50D5B48C-FB6C-4AB2-8AD3-E7F1173CEA47.jpeg
73EB37DE-D954-4C29-B75D-F7252DEAEFED.jpeg



My notes show different values than the pictures, but the angle difference remains the same.



CAF3B839-69B8-49E2-8FFF-3DF9B825E5A4.jpeg
85C2F19C-20FC-4D65-BA72-4B01B4934E4E.jpeg
649B8AA3-9775-4DDE-8FD0-A32A05236F16.jpeg
 
Sound like they part together wrong.
Take the rear part off and turn the shaft so all Ujoint line up
Tran [--------] Bearing [-----Rear----]
Back should be 90 deg off from the front
I hope this makes sense, i have trouble with words :\
 
I think phasing tolerance is only 1-3° iirc. I'd say it's a spline off, though I will say that most all fine spline stubs are keyed. Seen more than a couple that people just forced together. I personally would flip that bearing around since you need to fix phasing.
 
Chris_Keziah said:
I think phasing tolerance is only 1-3° iirc. I'd say it's a spline off, though I will say that most all fine spline stubs are keyed. Seen more than a couple that people just forced together. I personally would flip that bearing around since you need to fix phasing.
Click to expand...
Thats what I’m thinking either one spline or 180° plus a spline off.

The center support bearing looks newer but I’m guessing I’ll replace it since I have to remove it to flip
 
yager said:
Sound like they part together wrong.
Take the rear part off and turn the shaft so all Ujoint line up
Tran [--------] Bearing [-----Rear----]
Back should be 90 deg off from the front
I hope this makes sense, i have trouble with words :\
Click to expand...
Agree completely, and I understand fully.

I think they either have it one spline off or 180+- degrees off.
 
Mac5005 said:
Thats what I’m thinking either one spline or 180° plus a spline off.

The center support bearing looks newer but I’m guessing I’ll replace it since I have to remove it to flip
Click to expand...
Most of the time that style will come off ok, though a new one should only be $60-70. Try to buy a spicer if possible.
 
Back
Top