when i shift gears from D to R, i can hear a loud bang coming from the transmission i guess, it's loud and i can feel the blow budging the truck violently.
but, when i shift to R from P it goes in smooth and quietly. any thoughts?

another strange noise comes from the transfer case only when i put it into 4L - i can hear a sound slimier to a whistle while i apply gas.
i don't know much about transfer & transmission guts, so any help will be helpful.

by the way the truck is 90, k5, 5.7L with 700r4 and np241c.

thanks in advance, yarin.

 

What you are experiencing is caused by slop in the driveline.

The whine you hear is likely due to the ratio reduction. Is the transfer case fluid up to the proper level?

 

i need to check what "slop in the driveline" means unless you have some information for me.

i just put in new oil yesterday because i suspected the same thing, so there's a brand new oil in it and the noise stays the same..

 

By 'slop', I mean a buildup of clearances that can allow things to turn before engaging. In your case, it may be normal or excessive. YOU need to determine that part of it.

 

the only thing i can think of is the new detroit locker i installed recently, so i guess i can pin point the exact location of the blow, but how will i determine if this blow is making damage?, after all the truck shacks really bad when i change gears.

 

You can have slop in the transmission, the transmission to transfer case coupling, inside the transfer case itself, transfer case to driveshaft coupling, the u-joints, and the pinion to ring gear engagement that can all add up to a clunk when changing directions.

Was it like this before the locker was installed? Did you install a lunch box locker (installs into the open differential carrier) or did you install a complete new differential carrier center section?

 

i installed a complete new differential, with a new gear & pinion. I've used a dial indicator to make sure the backlash is within the recommended range.
and to be honest, i really can't remember if the noises came after or before the installment.

 

I would go back over the backlash setting as well as the tooth pattern just to double check. Do you have any abnormal noises coming from the rear diff while driving down the road?

 

the only thing i didn't do while installing the locker was to change the "position" of the pinion, i left it just the way it was and installed over it's setup, but eventually i got to a recommended backlash.
as far as other noises - sometimes when i apply the gas, release it and apply it again i can hear loud bang and i can feel the impact, but i feel it all over the truck so it's difficult to tell where the noise comes from.
and sometimes, the second time i push on the gas it goes in smooth, sort of speak. no noise and no vibration.

 

so, is it possible that even though the backlash is correct, there's a slop in that differential?
and, is there a way to isolate the noise, mean like removing the drive-shaft and hear if the noise is coming from the transmission or not?