Hey guys so I just installed a lift kit terra firma 2in and on the way home from my buddy's house I have noticed that after 25m or so driving when pulling out from a red light there was some shaking coming from the rear end when going from 10-15mph to about 20-30mph during gear changes. I was able to simulate the same behavior when manually selecting 1st gear and then moving 2nd.

The vibration did not occur on every single try. Maybe it was at a different rev idk.

Anyone knows what the heck?

 

You probably got a lot more wobble in the truck frame vs body now?
Guessing.

The gear change makes the truck frame and body wobble as compared to each other
and that puts the drive shaft at an angle where it may have the universal joint too far at an angle from drive shaft to the rear hub.

Just a wild guess but...

 

Another wild guess here... check your rotoflex (rubber at back of rear driveshaft). If it was marginal when you did the lift it might be sub marginal with the new angle. Easy fix if that's it.

But I think a marginal joint at front is a better guess.

When I did a 3 inch TF lift, my formerly happy front driveshaft of thirteen years began a rapid death spiral, so the new angles can cause issues for older shafts.

 

check ujoints and rotoflex as suggested

 

Maybe you're mistaking the rear end shake for what sounds like transmission shudder between shifts?

Because that sounds a lot like a transmission shudder between shifts.

 

Could possible be Watts linkage bushes failing now eccentuated by the extra lift or maybe the shaft Rotoflex binding due to extra lift. It might even be radius arm bushes failing.

 

So I have noticed that the shudder doesn't happen all the time. Truck drives and shifts normal if not put to extreme RPMs or above 70mph.

I believe it has something to do with the front prop and the rear rotoflex.

I am replacing the front shaft in the next few days and placing an order for a rear shaft with the conversion kit.

Should have both installed and all the fluids in the driveline replaced within a week.

Just got this truck so I don't really know what has been done to it. Rather not take chances.

Will post back with results when the parts are all in.

Thanks for the great feedback.

Oh btw, has anybody done any adjustment or removed the front shaft cross member? It really takes some clearance of the front if at full flex (although front will hardly ever need the full flex I believe) I am currently studying spacers or get a fab company to just cut it off and move the shaft section down 2 inches.

 

So, yeah, that sounds pretty much what i have been going through. Would you mind clarifying? Like, is it normal? Is there something about to go? what to look for? how to fix it?

Much appreciated.