Drive train noise/slack

[JCurtis]

Last week as I started to pass another car in 5th, I heard/felt two quick pulses of something WRONG in my drivetrain. The gearshift lever jerked with the noise and I thought "well, there goes the 5th gear nut. I've been waiting for that to happen. " After I got a lot closer to home I got brave enough to experiment. I could not duplicate the situation even under much harder acceleration, but found I could get noise/poping under deceleration in any gear. This weekend I pulled the cover from the differential, the driveshaft, the transfer case and the adapter housing from the transmission to look at the fifth gear nut. I can't find anything wrong, but have not split the transfer case yet. I am going to order a new 5th gear nut (and tool) while I think about it. I have read the post(s) about the retainer clip coming loose in the transfer case, but I don't seem to have excessive end play in the input/ouput shafts on mine. Does anyone have any ideas? My truck looks better in the drive when its not on jackstands.

 

[ChillyDog]

I think I have the same problems as you. When I let off the throttle quickly I get a nasty slamming noise from the driveline. It is most noticable in 4th or 5th but can be felt in all gears. If I slowly let off the throttle it's as smooth as silk. I had the new 5th gear and nut along with the new main shaft from Standard Transmission put in about 10,000 miles ago and the shop replaced almost everything in the transmission and checked over the driveline and could find nothing wrong. I'm wondering if it could be something in the rear end that is worn or loose?

 

[1tuffram]

I read in a post awhile back talking about the transfer case causing slack in the drive train. I think the problem was related to the chain stretching and more common in the standard duty transfer case (NV 241) than the heavy duty case (NV 241 HD).

 

[JCurtis]

I think my first post was misleading. The noise I heard did not occur when I started to pass but while I was passing. Anyway, I was sure that it was serious enough to leave metal evidence behind. Tonight I used a magnet to check the differential and transmission. They both checked fine. So, I took the transfer case in the garage and opened it up. Eureka! I found my evidence. I split the thing open and I found that the range fork was severely worn. Under power the small gear that it shifts forward and backward in the planetary assembly was just about to be in the neutral range of travel. I replaced the same fork last fall. That time I lost HI range almost without warning right after I came back from a long trip. It looks like I found the problem but not the root cause the first time and the same thing happened all over again. It may be time for another transfer case. Has anyone had this experience? Does anyone have any ideas on the cause of the fork wearing out so quickly (about 16000 miles)?