Rear driveshaft, trying to decide options (1 Viewer)

[NLXTACY]

About two weeks ago I started having vibrations while driving. Speed didn't matter because it only happened while I was moving. Since I had just done a complete axle rebuild roughly a month or so ago I of course focused a concerning eye on that. Found nothing. Then I chalked it up to my aging tires being at roughly 60k and being chunked up from my trips or just missing a weight. Since I needed tires anyway I ordered up a set. Yesterday I was trying to pinpoint an annoying exhaust noise when I found the u-joint on the transfer side of mt rear driveshaft was shot. I immediately ordered up form Matsuba u-joints from Georg. All is good, I will have those today.

I called up Wenco, the badass local driveline shop I've been using for 20+ years. My cost to replace both u-joints is $30 cash money and can be done in an afternoon. Money WELL spent. I get what I need and I'm on my way.

Or... I could ALSO have them go with a slightly thicker tubing AND make it a little bit longer and re-balance for my 4" lift. I'm considering .095" DOM which seems to be reasonable given what can be balanced and what the flange face will accept. But what to lengthen the shaft at given my 4" lift is what I'm unsure of. I will have the shop check the splines/tolerance and I know that the driveshaft works fine as is on a 4" lift but would an small increase in length increase its stability and strength, even if its an 1"? I think so. The driveshaft is currently out and I'm parked on a hill so no good way of measuring min/max driveshaft lengths. Hoping someone out there has this already done and has the numbers?

 

[maxamillion2345]

Doubtful the slip yoke is the weak point currently. I don't see the need to lengthen. Heavier wall sure.

 

[Cruzilla]

Your rear axle moves in an arc with the lower control arms, the upper control arms slow the pinion tilt but not perfectly. This is why you can use adjustable control arms to correct the pinion angle after a lift. I dont think your drive line length needs has really changed much unless you used longer lower control arms such as Land Tanks arms and they only increased the length by 1/4 of an inch or so. You need to have enough length in the slip yoke so it doesn't bottom out under full axle drop or articulation, I would be careful on how much you lengthen your drive shaft.. you may end up damaging your transfer case.

 

[Rwhat]

No reason to extend it. As far as I know the arch of travel of the rear link suspension doesn't ended the slip yolk out a lot.

I also extended a set extra control arms after I bent the 2. I sleeves them with DOM and extended them 3/8" IIRC
I didn't see much difference if any on the splines.

Also, unless you plan on wheeling it really hard replacing the DS tubing with DOM might not be worth it. $$ wise.

 

[NLXTACY]

Yup, I have LTs upper and lower control arms. I figured the change would only be 1/4 to 3/8"

 

[Cruzilla]

Measure your flange to flange (center to center) and give that data to the driveline shop and see what they say on extending your driveline.
I wold error on the side of caution as 3/8 of an inch will make very little difference unless you have minimal slip yoke engagement.

 

[Rwhat]

Nothing like driving over a curb and have a real 2 piece driveshaft. I know first hand.

 

[bloc]

How many miles on that u joint? (I know you have records)

Also why is the zerk pointed the wrong direction?

 

[mudgudgeon]

Also why is the zerk pointed the wrong direction?

Tough audience!


You need some spare travel with the rear axle at full stuff, or fully bottomed out. If you bottom out going over whoops, you'll compress bump stops.
If you're going to measure a length, take that into account.
I'd leave it standard length

 

[thatcabledude]

I thought "pay the $30 and be done in an afternoon" was a no brainer.

 

[mudgudgeon]

@thatcabledude You're forgetting the whole fix it until it's broken thing though

 

[ewillis]

Struggling with your tube length? Sorry not something I have experience with...

 

[thatcabledude]

Yeah I know.... This IS Joey we are talking about here.

 

[NLXTACY]

Struggling with your tube length? Sorry not something I have experience with...

Your wife is Asian, she gave you a pass

 

[Dragos80]

How many miles on that u joint? (I know you have records)

Also why is the zerk pointed the wrong direction?

Gosh!
It is Joey's thread. That's not a Zerk, it is a nipple. Geez.

 

[inkpot]

Gosh!
It is Joey's thread. That's not a Zerk, it is a nipple. Geez.

So what yur sayin is: "Joey's got an inverted nipple??"

 

[Cruzilla]

No, just that his nipples are pointing the wrong way!

 

[shocktower]

Oh my my, so ask everyone on the interwebs so, be honest, you want a full size man hood that is yours, since you boi L0L's at your stock model, and has the gurth of a Vienna sausage, wrong place for the answers. Ok no you don't need to lengthen it

 

[inkpot]

No, just that his nipples are pointing the wrong way!

Bass-ackwards?!?!

 

[chap79]

I'll say this; after measuring the rear drive shaft for compress and extended lengths I felt fully confident running my stock shaft after extending my LCAs 9/16". YMMV.