I believe the spider gears are going out in the rearend. When i do a hard turn you can hear and feel the gear "pop and cruch". Especially when I pull a loaded trailer. Its fine going straight or if I glid thru a tight turn. Has anyone changed the gears in the rear. I was told when I bought the truck the rearend was a spicer 3.54? But the tag under the hood states dana 70? 3.5 ratio.

SS

 

It sounds to me like you have a limited slip rear end that needs a dose of friction modifier. I would change the oil in it to a good brand synthetic RIGHT NOW!! Your towing habits require it. I don't want to mention brands here, but my favorite's initials are R. L. Everyone has their personal preference. It will tell you on the bottle to use the modifier or not. As to ratio, there is a metal tag on the cover bolts that will tell you what it is. Jim

 

Your truck should have a dana 70.

 

Yup, Dana and Spicer are synonomous. I think the way it works (let me know otherwise) is Spicer makes the actual gear, and Dana makes the houseing.

 

Spicer is just a brand name Dana Corp. uses.

def. give it a synth. lube job to see if it quiets up