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Popping Noise in 4wd

17170 Views 29 Replies 12 Participants Last post by  mega UAV
Ok guys i have a horrible popping sound when i come up my driveway in 4wd. Only seems to be doing it when going up hill or in the throttle (apply pressure to the drive train). Pulled front drive shaft and the u joints are fine. my front outer u joints have a little play in them but have for some time now. I have a fear the its the chain slipping in the transfer case.:banghead: Any idea's to try before ripping into the tcase? Thanks!
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Get someone outside the truck and try to pin point the sound so they can tell you weather the sound is coming from the middle of the front. I hope its not that chain but UV joints aren't fun either. I work at a deere dealership as a tech and we always have someone standing by the machine when checking the front UVs to see if that is popping. If there is quite a bit of play I'd change them before they break because when they do it is a lot of damage and they should be pretty solid and not really able to move by hand much.
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Has anyone had the issue of this with the electronic 4wd not engaging all the way? If so what was involved to fix the issue? thanks
Sounds like your chain to me... it's not to hard to replace. Just did mine a little bit ago. Chain is around 150 bucs.

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If it not your front axle u joints then its most likely going to be the tcase. Drain the oil in the tcase and check for any metal pieces. When mine blew there were a few fragments of the chain that fell out.
Good luck mine had to be completely rebuild after it started making noise.
You did not indicate whether removing the front driveshaft eliminated the problem. Assuming that some type of posi unit has never been installed in the front end, removing the front drive shaft should eliminate the "popping" for either bad driveshaft u-joint or axle u-joints. I wouldn't chase after the transfer case until I eliminated the cheaper and easier to fix u-joints. Since you indicated slack in your axle u-joints I would be reasonably sure THAT is where your problem is located. If slack is present then the seals in the u-joint can no longer hold out moisture causing corrosion to all the needles in the u-joint. Most likely the u-joint caps that are still tight are corroded causing the needles within to "ride up" and bind the u-joint. The pop you here is when the pressure is great enough for the needles to suddenly "unload" releasing the pressure. While not as sure an indicator as with spicer u-joints, inspect around the seals of the u-joints for rust colored residue on the cross. This is a sure sign of a bad u-joint. I'm curious about when your driveline was still installed, if the popping only happens while in a turn or at least gets worse. If so, that would solidify you axle u-joints as the problem.
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You did not indicate whether removing the front driveshaft eliminated the problem. Assuming that some type of posi unit has never been installed in the front end, removing the front drive shaft should eliminate the "popping" for either bad driveshaft u-joint or axle u-joints. I wouldn't chase after the transfer case until I eliminated the cheaper and easier to fix u-joints. Since you indicated slack in your axle u-joints I would be reasonably sure THAT is where your problem is located. If slack is present then the seals in the u-joint can no longer hold out moisture causing corrosion to all the needles in the u-joint. Most likely the u-joint caps that are still tight are corroded causing the needles within to "ride up" and bind the u-joint. The pop you here is when the pressure is great enough for the needles to suddenly "unload" releasing the pressure. While not as sure an indicator as with spicer u-joints, inspect around the seals of the u-joints for rust colored residue on the cross. This is a sure sign of a bad u-joint. I'm curious about when your driveline was still installed, if the popping only happens while in a turn or at least gets worse. If so, that would solidify you axle u-joints as the problem.
^^ second that. Might as well fix those first. Don't want to wreck those axle shafts cause they aren't cheap.
You describe streched chain exactly. It is not a difficlut job. Can do without pulling entire unit. There is a snap ring that will spoil day so get a FSM to be sure get it apart and back together. Split the case and remember to keep pressure on shafts to keep from falling out. Generally you don't need to replace sprockets but have found the support bearing in gear train to wear. It will turn smooth but can have up and down looseness when bad.
If bearing is bad you will think chain has streched again after a couple months.
Running in 4WD on good pavement is generally cause of streching. Does not take long. Just a few miles of highway driving will get them.
You describe streched chain exactly. It is not a difficlut job. Can do without pulling entire unit. There is a snap ring that will spoil day so get a FSM to be sure get it apart and back together. Split the case and remember to keep pressure on shafts to keep from falling out. Generally you don't need to replace sprockets but have found the support bearing in gear train to wear. It will turn smooth but can have up and down looseness when bad.
If bearing is bad you will think chain has streched again after a couple months.
Running in 4WD on good pavement is generally cause of streching. Does not take long. Just a few miles of highway driving will get them.
^^^ Dozer was a big help prepping me for mine! Can't remember if I'd thanked ya or not but thanks man! And that snap ring can be a real time thief lol get the tool like he said.

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Ok so drained what little fluid i had in my transfer case. and by little i mean little. flushed it with some fresh and drained it and still no metal but the noise is def. coming for the transfer case. I pulled the t case out today pretty easy job. looking through the drain and fill holes i can see the chain and i can push up on it with a screw driver. should there be much play in that chain or is it fairly tight? Also where have you guys been getting your chains? Is it a "Dealer Rip You Off Part"? Thanks
Got mine for 150 delivered to my door, part is 140 and change, transfer case express is where I got it. Ships from Cali or SC ... they have it all... :thumbup:

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Got mine for 150 delivered to my door, part is 140 and change, transfer case express is where I got it. Ships from Cali or SC ... they have it all... :thumbup:

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Thanks Man ill try there.
Well it was definitely the chain. Got one the next day delivered from dealer for 210 and shes put back together now.
Good to hear man... did you try tcase express?

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Good to hear man... did you try tcase express?

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I didnt and the price at the dealer for next morning delivery was hard to beat. plus being a factory part vs. a aftermarket part might be a little safer too. Thanks for the info though
i hear a pop in 4wd also but thats only when turning so im thinking mine is only the u-joint. I dont mean to steal the thread but i just wanna get yalls input
i hear a pop in 4wd also but thats only when turning so im thinking mine is only the u-joint. I dont mean to steal the thread but i just wanna get yalls input
Could be but should do it in 2wd as well.
Could be but should do it in 2wd as well.
It does it in 2wd but not much but when its in 4wd It happens alot more.
It does it in 2wd but not much but when its in 4wd It happens alot more.
Sounds like ujoints on the axle then to me. If you crawl under the truck with a pry bar you should be able to put pressure on them and see if there loose. some times you can move the drive shaft back and forth in 2wd and see the slop in the caps as well.
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