Curious what your opinions are as to the cause of this:



Little background. The same time I installed the new aftermarket rotoflex joint I also replaced the alignment bearing in the driveshaft. Replaced the center and both front and rear diff fluids with Valvoline 85w 145 as per Disco Mike. Added BG gearing additives to the front and rear diffs as well as a diff additive to the center diff.

Weather conditions since then have been very fluctuant. -17f to 60f.
Did have a vibration within about 800 miles after performing all this work. Vibration happens only when taking off to about 25mph then it smoothes out. When I stomp on the gas and it goes to downshift I get a slight vibration same when it goes to upshift. I am guessing it is due to the cracked rotoflex joint.

Could this be due to the thicker fluid?

 

You said it is an aftermarket rotoflex, what brand name is it and where did you buy it at?

I don't know but I would question how the viscosity of the fluid could be responsible.

Could not tell much from your picture but it appears a few chunks are missing?

 

They all tend to get a bit of hairline "cracking" around the bolt holes but that looks more like a big ol' chunk.. unless I'm just not seeing the pic all that well. The diff oil should not cause additional resistance that acts against the driveshaft.

What lift (if any) do you have? Did you also service the ujoint in the rear drive shaft?
Vibes could be from that "alignment bearing" (i.e. Centralizing peg) job...

May be worth pulling that apart again and make sure the bearings on the pinion shaft are seated properly and still good. Check the pinion flange nut... did it loosen slightly after running? By that I mean, if the bearings weren't seated properly, when you tighten the nut it may feel tight however, when driving the bearings could have shifted and caused the nut to actually be loose.

 

I need to become more familar with the things involved here, I had to replace my rotoflex but I waited too long and damaged the flange. I have a replacement, but have not gotten around to doing anything on it yet. What else might I need?

 

There are some small chunks missing. I do not have a lift. Just 245 75 16 MT KM2 tires. Did not have a vibration until I did the service. I did not service the ujoint other than lubricating all the zerk fittings. Did that on all of the drivetrain. I will have to pull it apart when replacing the rotoflex today, I will check my alignment bearing as well.

I will add that when I take off in the morning the truck moves like I am driving through tar. Here is my theory on the fluid viscosity. That thick of fluid at cold temperatures is at its thickest point. As it warms up I move around just fine. That is where I got my theory of the fluid causing unnecessary stress on the drivetrain, this in turn will show up at the weakest point ie the rubber rotoflex joint.

I truly appretiate the input. Want to be sure I am not just tossing another rotoflex joint on without solving the cause.

 

On your 245/75's do they rub on your Rover? And so you rep those tires on a stock rover? The reason I ask is because I'm not planning on getting a lift just yet but I'm getting an extra set of wheels and some a/t or m/t to use for off road only. Or should I just get soem 235/85's and slap those on? Sorry for the thread hi-jack haha.

 

The only rub on hard turns and only very slightly. offroad they work amazing. I am planning on a 2" medium duty TF lift in the next few months. I would definately recommend this size esp if you are thinking of getting a lift soon.

 

Britpart rotoflex joints are known for failing with low mileage.

 

I bought it from my local import car parts source. Not LR. I read a while back that some people had good luck with aftermarket and some did not. I think given that I 4 wheel on some pretty rocky terrain that may have caused this as well.

 

You may want to consider either the upgrade kit that does away with the rotoflex or a rear driveshaft from a later model that does not have the rotoflex.