Replacing U-Joints on 2010 Silverado

[Service1956]

Axle end u-joint is bad. I want to replace both while it is out. I do not know if the front yolk that slides into the transmission tail shaft is keyed to only go on one way. If not, should I mark the drive shaft with a marker and extend it to the tail piece on the tranny? And should this also be done with the rear part of the drive shaft and rear end so the drive shaft goes on exactly the same way it came off?

[txab]

It's keyed.

 

http://www.truckmodcentral.com/forums/100611-post1.html

[Doug_Scott]

The link supplied does not show anything being keyed. It is always a good idea to mark driveshaft and yoke phase or relationship. No sense in marking u-joint if you are replacing though, but still mark phase of yoke to shaft.

 

I have not seen a slip yoke with a master key, but, mark the parts anyways. Output shaft on transmission will not move unless someone slides a yoke on and turns it on you, On 70's and 80's Dodge products, getting the slip yoke out of phase on reassembly would not cause any issues, but, get the shaft out of phase with pinion flange would cause a pulsing deep resonent vibration starting at 60km/h. Luckily there is only two ways to connect to pinion flange, so just undo u-joint straps, turn shaft 180 degrees and connect it back up.

[Jsdirt]

I've always marked driveshafts anyway just to preserve the factory balance ... if there is such a thing. Not critical, but I'm picky like that.

[MikeNH]

I would absolutely say its critical. I was taught to always mark up the driveshaft before pulling it.

[Doug_Scott]

It is one of those things that you only need to have to redo it once to realize marking the shaft is quicker than having to bring it back in, up on the hoist, undo the shaft at the rear diff, turn shaft 180 degrees, then put it all back together, and back out for a road test. You can mark the shaft with anything(ballpoint bic pen excepted), even a flat screwdriver can put a deep enough scratch to make out the marks.

[mike94silverado]

Another thing is make sure your replacement joints have grease fittings many aftermarket ones do but some do not

 

 

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[MPCOA]

Some swear by nongreaseable ones, supposed to be stronger. I could only find grease fitted spicers though.

 

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[Jsdirt]

Thanks for your service, MPCOA!

 

I prefer the greaseable ones. I used to have myself on a schedule where ALL fittings on the vehicle got grease at every oil change. Since Amsoil can go 8x that long, I try to remember to grease everything every 3k - just one pump usually, unless I can see/feel the grease pressure.

 

 

I've screwed up a few times (always in a hurry ...) not marking driveshafts on the older stuff. Noticed a very slight vibration, but nothing bad enough to make me want to do it twice. This of course was my OWN vehicle .. gotta slow down and think when working on other people's equipment. Hard to do on flat rate ....

[gmtech4]

i read thru this pretty quick,

 

there IS NO KEY OR MASTER SPLINE on a 1 pc shaft ,,,,it is a balanced unit ,,,,,it doesnt matter where you put it ,,,,,

 

2 pc shaft has a master spline at the rear of the front shaft and front of rear shaft to maintain phasing of u joints ...

 

BAMMM lol

[Doug_Scott]

i read thru this pretty quick,

 

there IS NO KEY OR MASTER SPLINE on a 1 pc shaft ,,,,it is a balanced unit ,,,,,it doesnt matter where you put it ,,,,,

 

2 pc shaft has a master spline at the rear of the front shaft and front of rear shaft to maintain phasing of u joints ...

 

BAMMM lol

 

No idea why, but, rear wheel drive Chrysler products from the 70's and 80's when using the typical "Hotchkiss" single drive shaft, would give a vibration at approx 40mph if driveshaft was installed out of phase. It was a pulsing hum type vibration. If you simply undo the 2 straps holding rear u-joint to pinion flange, slide drivesharft forward(forward as in towards front of vehicle) to disengage, then rotate shaft 180 degrees(one half rotation), slide driveshare rearward and reinstall the two straps.

For whatever reason, this would stop the vibration. It cannot hurt to simply mark the shaft on disassembly. Good habit to have.

Something else to note, u-joints that have the zerk grease fitting in the cross of the joint(as opposed to the fitting installed in the cap itself), the fitting must be on the shaft side of the cross.