when im on the parkway around 55 60 or 70 when i back off lightly on the gass it feels like a really hard grinding coming from down below, then when i gradually step on the gas only in the beginning the same grinding noise. as i step on the gas a lil more it goes completely away.
So when im driving normal its fine but it only does it when i slowly back off the gas seems to be right before it coasts and then when i go from a coast to under slight acceleration it does it also then goes away.
reached down and felt the 4x4 shifter and you can feel it in there but its kind of vibrates the whole truck. any idea what this could friggin be?!

i have a 10 month old mega viper trans in there so i sure as hell hope its not that or im up you know where without a paddle.
please help me quick

( guna go out and check transfer case fluid to see if theres any shavings, checked trans dipstick and all seems fine there, havent taken off pan yet )

 

also wanted to mention it does this in overdrive, or when overdrive is off also.

 

Crawl under your truck and start shaking things.... see if anything in the driveline is loose. may also want to pull the rear shaft, and check and see if the snap ring on the output shaft of the t-case has failed.

Does the TCC engage when overdrive is turned off??? Wonder if it might be torque converter...... Not sure on that one.

 

i pulled on everything under there and nothings loose, and i most likely will take the shaft off tomorrow after school its to dark now, and yeah you can feel it engage its the same as its always been, its weird how it does it only when your light on the gas from a coast or when you back off gently on the gas to coast if you hold it in a certain spot it will just do it until u let off or hit the gas more

 

+1 on checking the snap ring on the t-case tailshaft.

 

im hoping thats all it is, its really annoying. sometimes when i let off the gas or hit the gas hard u can hear a clunk.

if its the snap ring, transfer case saver will be purchased tomorrow

 

and it only started like yesterday but today it got a lil bad once or twice on me im praying on that stupid snap ring and thats it

 

anybody else have any input?

 

check ur rear pinion yoke, mine was makin that same noise and i got under and shook lieterally everything till i got the and the nut on mine had come damn near all the way off, i tighten it down pretty friggin tight and the noise went away, i had thot it was my tranny but mine had been rebuilt and had only been in the truck for about a month, and oh yea does ur truck kinda jerk every once in a while when ur on the highway or doin more than 45ish?

 

No it doesn't really jerk. The only time it does this weird grinding is after the torque converter locks and I back off the gas or lightly step on the gas