I've noticed that when I let off the gas while in gear (5sp manual) then accelerate again it feels like there is a big clunk, like there is a bunch of play in the drivetrain or there is a broken mount on the engine or t-case. I had a couple friends rock the truck back and forth in gear while I was laying under it and I don't see much movement in the mounts, the rear one that supports the t-case and tranny only moves up and down a little. Not nearly as much movement as it feels like there would be when driving. I also couldn't see any movement in my u-joints. What else should I check? Could this just be slop in the tranny? Are the nv4500s known for having a bunch of slack in the gearing? You cant hear any noise, you just feel it, like what I would expect to feel with a broken mount... I'm stumped.

Jason

 

Is this a new prob or are you a new owner?

 

new owner, I'm not sure how it should feel to begin with...

Jason

 

Depending on the mileage, there are alot of places for wear. Starts at the clutch and works your way out to the rear end. After a few hundred thousand miles it all adds up. I can get a good clunk in between gears if I am hard shifting it. But from the clutch splines to the transfer case, to the output shaft, to the intermediate shaft to the diff.. Lots of room for wear. I would just drive it a while and check the rear end fluid for some sparklies.

 

That sounds different than when my clutch throw-out bearing, well, decided to throw itself out. That was a very distinct noise that actually went away when the clutch pedal was depressed. It was gradual to a point and when it let loose I thought the truck would shake itself silly.

Your situation sounds a lot more like gear backlash than anything, and that's likely coming from the differential. If there's a plug with a magnet, you might start with checking that - better yet, go ahead and change your diff fluid (replace the gasket as well) and inspect it thoroughly while you're in there.

Good luck - let us know what you find.

 

It has a newer rear end with taller gears out of a 01. I know it has fresh fluid, though I don't know if he check the gear backlash. It only has about 70k miles on it. (it was out of a wrecked truck). Also, the clutch is new. Where can I find the specs on the rear end for the correct measurements for gear backlash? That may be something worth checking. I would think if I had a bad mount it would be obvious to see, since they are rubber.

Jason

 

I had a clunking problem similar to yours. It turned out to be that my two transmission mount bolts were loose. The trans would rise up, later to clunk back down.

 

Try lying under the truck with it off and trying to manually spin the driveshaft, both in gear and out of gear. I would guess that you will find that your play is in the rear end.

A note of caution on the rear end, if it has any miles on it, I would leave it alone or you need to replace everything. Once the gears have started to wear, if you adjust the backlash, it will whine forever and annoy you.

My truck has a lot of slop in the diff and I have just learned how to drive so that it isn't an issue.

 

4WD's have a lot of backlash in components when added up. Front and rear difs frequentlly have 3/8 to 1/2 inch backlash when measured at yoke. A little more in u-joints, a bunch in transfer case wth chain and gears and manual tranny also. Don't worry, you'l know when you have a real problem.

 

my best thought if all the simple things like ujoint and normal backlash are not it Id say its the 5 gear syn ring this is what hooks up 5th gear I have one sitting on the bench as we speak with this problem,This will only do this in 5 gear if its that problem other wise a ujoint will do it in all gears

 

I agree with dozer. My 97 has some of the same slack and "clunking". My guess is that the transfercase chain is stretched somewhat and allowing noticeably more slack to be present that if the chain were new and tight.

Steve

 

My 96 does the same . I know that the teflon type coating on the slip joint on the front section of the rear drive shaft is wore off. I'm not sure that that is causing all the action but I know it's not helping . You might want to check that on yours.