So i put my truck.in 4wd low today and you start moving forward and it moves a little bit then the body in the back starts flexing like the drive shaft Is turning but the reared isn't any clue what Thats could be oh and it dosent do it everytime but it does it alot

 

Flexing like....twisting? Bending up? Bending down?

 

like one side of the bed moves some and i can here the leaf springs squeak

 

So...twisting? Do you feel it or see it? It could be the low gears in the transfer binding up, not sure if something like that could cause this...or even happen. But if its twisting the back end of your truck like it sounds it is...the torque from something trying to twist/spin around could be doing it. Is it only in 4-low that it does this? Like...(sorry if I explain this wrong) when your have your foot on the brake and your in drive and you floor the gas some, you can feel the truck lean to one side because of the torque of the engine.

I'm not a very good mechanic so anyone else please feel free to correct me.

 

Has the truck been re-geared??? Sounds like someone regeared the rear, and planned on doing the front some other time, but never did. Therefore causing driveline bind and siezing everythig up

 

x2

 

could be the gear s like they said.

but where were you when you tried out the 4low?

if you were on soild ground it is going to act up.

 

I thought maybe gears cause he said the po geard.it but then put a new rearend so i bet he put a stock one in it it feels like your running something over on flat road

 

That doesnt mean that the stock rear end he used had the same gear ratio as the stock from that particular truck. Did it only act this way in 4lo, or did it do it in 4hi as well?

 

I only tried 4lo