Bad clunk when goin from reverse to forward and visa versa

[Chevy1925]

Ok so im pretty stumped here. Ive got a bad clunk when goin from reverse to forward and visa versa. I have only noticed it when it ahd sat on an incline or decline for a while course my parkin spot is on an incline and most places around town have a hilly parkin lot. This aint like a little clunck either. Its like some one rear ended me or i hit somethin it bangs so hard. It will only do this once per driving cycle, so untill you park it again you cant get it to do it again

here is what ive checked: U joints, no slop, binding or rust comin out; rear end gears are all tight and no abnormal wear; did this before tranny was rebuilt by mikeL aand still didnt go away; replaced carrier bearing 8 months ago and the bearing is showing some bad stress crackin in the rubber and one peice is torn some; ive greased the slip yoke at the t-case and i mean packed with grease and also the slip yoke after the carrier bearing, no change.

m runnin out of options here and this is gettin really bad. i travel alot to phoenix (150 miles each way) and dont need what ever it is breakin on me. I have noticed that the carrier bearing moves about a 1/2 forward or back with in the rubber mounting portion when put in either direction but thats all. All i can figure is that its either carrier bearing or somethin in the t-case.

any ideas? anyone know fo a bigger carrier bearing to put on cause i really dont like the factory one for what i do

 

[mmangels22]

I don't know dude maybe a loose mount somewhere.

 

[Chevy1925]

see and ive looked all over under the truck. everything is tight. even pulled the tranny mount and looked it over really well but its in great shape.

 

[maxaholic]

I'm not much of an auto guy but maybe it's from the teeth or gears in a bind from being on an incline. Does it do it when on level ground?

 

[ICULKN]

Check CV joints it is a 4X4?,

 

[Chevy1925]

I'm not much of an auto guy but maybe it's from the teeth or gears in a bind from being on an incline. Does it do it when on level ground?

see and i thought that too but its not because i could drive for a few seconds and get about a half a tire rotation sometime before it clunks

Check CV joints it is a 4X4?,

Not that, it is for sure comin from the rear

 

[T2CH]

leaf spring ubolts?

 

[ICULKN]

Need some one out side of the truck and do what has been making the sound while some is checking to help narrow it down.

 

[maxaholic]

I just had a brain fart. My buddy had the same problem. It ended up being a fried bearing in the transfer case. The oil pick up or something another came off the pump and it was running dry. He had to buy a new shaft, pump, and some gears. Hope this isn't your problem. But it is beginning to sound exactly like my buddies.

 

[Chevy1925]

Need some one out side of the truck and do what has been making the sound while some is checking to help narrow it down.

i did, could not really see anything other than the bearing moving

I just had a brain fart. My buddy had the same problem. It ended up being a fried bearing in the transfer case. The oil pick up or something another came off the pump and it was running dry. He had to buy a new shaft, pump, and some gears. Hope this isn't your problem. But it is beginning to sound exactly like my buddies.

damn thats not what i wanted to hear... i fixed my pump rub two years ago but it had been dry for atleast two months that i knew of. guess ill be tearin into the t-case hear soon as i was really thinkin it may be that. Gunna check around some more before though

 

[SteveFord]

Does it clunk after you feel it engage. Mine likes to do this ever since I reflashed my tcm for some reason. My other 02 I had a few years ago did the same thing. You put it into reverse then right after it engages you fell a clunk. Mine does one even further. If you put it into reverse and take off as soon as it engages it won't clunk until you slow down in reverse to around 1-.5 mph then it will clunk. Then you can sit there and barley touch the throttle while in reverse and it will clunk. You can get mine to do it numerous times as you sit there in reverse. I've sat there with my truck so it can't move in reverse and while looking under my truck it touched the throttle and watched the drive shaft what I would call flinch each time it touch the throttle. The rpm's might move 25 rpms. I've done a full reflash(used the same 01 os), looked at everything I could in the tcm and ecm and can't see what or why it does it. The tranny is not hurt or anything wrong with it. Undone the plug on it and it won't do it. Goes right into reverse. Either something in my tcm/ecm that I can't see with efi is making it do it or something else electronic. Drives me nuts but I'll figure it out. My last 02 did this with the quadzilla/edge stack and it didn't stop doing it for awhile then one day it was over and my friend that has it said it hasn't done it since. I know I've read on here where someone used the 02 os and their truck got the reverse clunk like mine. I was going to try and reflash mine with a different os but this is more annoying than anything and will wait to see when it warms up outside if it goes away. Did you do a fast learn with your ppe or anything like that?

 

[zlonsway]

Mine does this sometimes too. I think it is the slip yoke on the front driveshaft. I have an 03 CCSB with one pice shaft.

 

[jonathancasey19]

i get it too....02' ecsb. rear drive shaft, u-joints, t-case, u-bolts, cv shafts, wheel bearings, all front end components replaced still get it. mine only does it when i put it into reverse about a half a second later before i let off the brake. it's not lash either....

 

[Chevy1925]

Does it clunk after you feel it engage. Mine likes to do this ever since I reflashed my tcm for some reason. My other 02 I had a few years ago did the same thing. You put it into reverse then right after it engages you fell a clunk. Mine does one even further. If you put it into reverse and take off as soon as it engages it won't clunk until you slow down in reverse to around 1-.5 mph then it will clunk. Then you can sit there and barley touch the throttle while in reverse and it will clunk. You can get mine to do it numerous times as you sit there in reverse. I've sat there with my truck so it can't move in reverse and while looking under my truck it touched the throttle and watched the drive shaft what I would call flinch each time it touch the throttle. The rpm's might move 25 rpms. I've done a full reflash(used the same 01 os), looked at everything I could in the tcm and ecm and can't see what or why it does it. The tranny is not hurt or anything wrong with it. Undone the plug on it and it won't do it. Goes right into reverse. Either something in my tcm/ecm that I can't see with efi is making it do it or something else electronic. Drives me nuts but I'll figure it out. My last 02 did this with the quadzilla/edge stack and it didn't stop doing it for awhile then one day it was over and my friend that has it said it hasn't done it since. I know I've read on here where someone used the 02 os and their truck got the reverse clunk like mine. I was going to try and reflash mine with a different os but this is more annoying than anything and will wait to see when it warms up outside if it goes away. Did you do a fast learn with your ppe or anything like that?

Ya know, now that you mention that. I had my TCM reflashed at the dealer to get the 5th gear lock out feature and it started not too long after that. I also get a curise control surge when on the freeway goin down a hill that you jsut barely need to push the gas to keep the same speed. really annoying. As far as the clunk though, it never did it over the summer but as it got colder it started gettin more and more noticable. I know that reverse is in fact engauging though as it will back up with or without any throttle input then clunk. this mornin i backed all the way into my spot with out a clunk till i hit the brakes kinda hard to see if it would and sure enough it did.



Iver pretty much replaced everything as well except the big stuff (t-case and rear end) and it keeps doin it. Tonight or tommorrow im gunna pull the back half off the t-case to see how it is inside there and if it is a bearing or something. If not, ill try a carrier bearing and if it aint that.......... well we jsut wont think that far ahead lol