Driveshaft help

Hey all so my driveshaft broke the other day and i have a replacement. My question is that i noticed some vibration when i was driving up to the point the shaft broke. I knew it was the u joints but im curious since i have a replacement now should i take a look at the gears as well since there was that vibration?

Also has anyone found a good write up on installing the new one?

 

Check for play in the pinion bearing. If there is none just replace the shaft and move on.

 

Any advice for another issue? I had it break on the expressway and then drove it home in 4wd using the front wheels. Any tips for being able to line it up/balance properly?

 

Assuming no damage was done to anything under the truck the new one should just bolt in. May have to jack up one of the rear tires to spin the pinion flange until it lines up with the t-case flange.

Is your new driveshaft brand new, or used? If used you might want to consider doing a new carrier bearing and 3x u-joints while its out of the truck. But that depends on how many miles on it, not strictly necessary.

 

As long as the u-joints are in phase (lined up) your good, the t-flange & p-flange are not part of the balance equation.

 

Are you lifted at all?

You may need a carrier bearing drop or axle angle shims to get your flanges within 1° of parallel to each other and the front half shaft and rear half shaft's also within 1° angle of each other.

 

Just to clarify, would you check for axial play, radial play, or torsional play?

 

Yes.

 

I assumed that radial and axial play are bad news. But I guess I'm really curious about torsional/rotational play. There is always some level of backlash in a geared assembly, so there will be some rotational play, even if it is so small it's negligible--so how much is too much when we are taking about rotating the pinion flange on the rear diff? 1 degree? 10 degrees? 0.1 degrees? 0.01 degrees?

Just trying to get a feel for what is an acceptable ROM for our trucks.

 

You'll never accurately measure pinion to ring gear lash without pulling the 3rd member but disco the drive shaft and give it a twist it's more of an experience feel measurement which is hard to judge online but if there's a problem more than likely you'll know either from diff noise or it just feels sore loose.

Same with side to side and in an out.

 

I gotcha, experience is definitely worth a lot for something like this. I can torque things to spec without a torque wrench like nobody's business, but I've never rebuilt a diff (I'm familiar with the process, but have never done it myself), so I'm not up to speed on feeling out play due to back lash.

I rebuilt my DS recently and while it was odd the truck I found that I did have some rotational play at the pinion flange, hence the question. Definitely more digging to do.

 

Yeah I'm pretty good at feeling a diff out but dunno how to translate that experience beyond you have to go but hands on a bunch and eventually you'll get a literal feel for it.

I always use a torque wrench regardless because I'm extra™ but my uncle has been a mechanic for longer than I've been alive and we joke about his "calibrated" forearms because he never uses one and I've even gone behind him with a wrench before and everything always seems to be ±10% of value.

Me personally; differentials aren't worth the headache, I can do everything myself (to include diffs) and usually do, but diff's I'll still leave to ECGS.