Rear End Question

I am no ‘Mr Goodwrench’ but I would think the ratios wouldn’t matter, until you engaged the power divider.
Speaking of that, years ago drove a company truck with the same symptoms, put the truck OOS many times for the issue, mechanics, and mgt. cancelled the work every time claiming it was ‘ all in my head, you just don’t like that truck’.
Well one day, a city driver got in the truck, put it in gear, and ‘BANG!’, the power crapped out.
Week later got truck back from the shop, and lo, and behold, the vibration was completely gone.

 

You absolutely must have same ratio front to rear. Just because diff is not locked, power can and will be transmitted through it. They are fighting eachother. Not a good deal. You need to stop operating it asap. One of them is going to leave the group discussion.

 

If you truly have different ratios they aren't going to last long. First of all if they are different and you engaged the power divider in anything but pure mud or ice bad things will happen. Obviously the front and rear axle will be trying to turn at different speeds and they aren't going to like that.

Secondly it doesn't matter if the power divider is NOT ENGAGED. Power flows through both axles. There isn't one axle or the other that always gets the power. Cruising down the highway power basically flows to all 4 wheel ends assuming all things are equal. When ANY of the 4 wheel ends looses traction that wheel will spin. Could be any of the 4, which everyone has the least traction.
If you have new tires on one axle and worn out tires on the other they aren't the same diameter and you can run like that without problems but it is harder on things.

Basically what I'm saying is I highly doubt you have different ratios

 

Poor power divider is getting the crap beat out of it.

Power divider and axle spider gears are meant to compensate for minor speed variations between the wheels ends (ie turning corners, slightly mismatched tire heights). They aren't designed to compensate for that much variance and on a constant basis either.

 

Yeah. I was going to say that. The ring gear and pinion are made for the majority of movement and the smaller gears work best not moving and just transferring load. I was recently looking at power dividers to figure mine out and I believe that's a planetary gearset too.

Scratch that, just a regular spider gear setup and a pass through shaft through the front of one of the gears into the rear, with a collar to lock the two together. I knew it was something like that, just didn't remember the specifics because it's a bit weird.

 

A way of ck. to be sure the rears are diff. are the same, is to jack 1 side of tires off the ground and mark a spot on both tires and on side of driveshaft on ft. side of rear end, turn the tires 1 round while looking at mark one driveshaft to see how many times the mark on driveshaft turns with the last time in quarter of turns write it down and turn the other tire and mark it down on the paper and you will find if the marks on drive shaft land in same place you have same rear gears, a driveshaft out of time may be the problem, look if all the end caps on both driveshafts are lined up a single spline off will make it vibrant. like crazy

 

Here's a example of how bad drive line angles can cause vibration.

 

Would that even make it more than a few miles if it had those 2 different ratios?