Transfer case question.

[wasonha]

Hello everyone and thanks in advance. I have a 99 xploder w/bw 4405 transfer case. here goes: towed a trailer from ny to florida recently. once i was here i started to notice a kind of jump/clunk, kind of like a sputter (at the very start i thought it was a bad injector or some kind of fuel restriction). it progressively got worse, then it started to do it around 30 to 40mph, then would be o.k. until i got in that range again, and now it almost sounds like a machine gun doing it constantly,with a griiiiind clunk jump clunk griiiind ka-chunk... not always at first but usually at 20 and then after it starts it's noise it does it so bad i can't give it any gas barely at all, in fact on my way back from orlando at the very end of the trip i was doing about 5mph and another 5 miles and i wouldn't have made it back, any gas at all would cause it to do it real bad, also i should note that it never does it when coasting, and cornering doesn't make it worse, only when giving it gas...so i've been trying to diagnose exactly what it is. i automatically assumed it was in the rear diff. so i took the cover off and to my surprise everything looked good. of course, first i checked the ujoints. i put it up off all fours and ran it and with the rear diff. cover off and checked it all out, and it kind of seemed like maybe the teeth on the rear axle spindal might have been bad by the way it was acting, so i took off the axle to see since it wasn't that hard to do, nothing wrong there. then i got the idea, duh, take off the rear drive shaft and see if you still get the noise, which i did and still got the noise (seemingly worse, but i think it was coincidence). so i thought for sure it was the t-case. all the while, i noticed that the front driver tire moved up and down rythmically, but that didn't seem like too big a deal, and i thought i'd just mention it anyway. then i thought, maybe it's the t-case motor, so i took that off and turned the key thingy to H, and the noise seemed to go away. i thought, great, and ordered the motor, put it on, and still the same problem. so next i took off the front driveshaft (left on the rear) drove it and that didn't make a difference. then i took off both drive shafts and no noise. so i was researching and noticed something about vaccum lines for the hubs (IWD or whatever) and couldn't find anything like the motor that is described so i assume it is the auto locking hubs (i should note that the front diff. did have one hose attached to the top, which was split at the end so i cut it and fixed it and that didn't help at all)...so now i'm at the point of taking off the rear driveshaft and putting the front driveshaft on to see if driving it with the front driveshaft only makes a difference, since when it's in the air i can't get it to make a noise anymore....it seems that the only time it will make the noise now is when it is under a load (although the first time i had it in the air with both driveshafts on it made the noise)....anyway, it's hard to describe two days worth of struggle in as few words as possible but here it is...if anyone has any ideas or suggestions i really appreciate the help, i have no problem buying a used t-case but i'd hate to dish out the money only to be left with the same problem...also, the front driveshaft is really hard to get on, it seems like you need 4 hands b/c of the way the ujoints are held on to the front diff., and it's clicking now with all four tires off the ground, which i'm going to have to remove and re-set it before i try what i said (driving with only the front driveshaft), any tricks/hints on that would be cool also...again, i can't thank you enough for any help

 

[jhoule52]

we had the same problem after 30 miles a hour you could not give it any gas it was the speed control sensor it cost us two hundred and fifty dollars to fix including the part at a tranmisssion shop

 

[wasonha]

Thanks for responding

Did your's have a code? Mine doesn't have a code, and usually (well, almost always) there is a code when a speed sensor goes bad...but does anyone else think the abs speed sensor could cause this, or is it directly related to the abs and not the locking of the hubs?

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the transmissions & transfer cases section.

 

[joecrna]

You are getting your 4WD (front axle) confused with the first generation system. You don't have a vaccum line to the front axle, just a vent hose. You don't have locking hubs, yours is constantly "engaged" as it uses CV joints.

You seem to be doing all the right trouble shooting. You say it only makes the noise when under power, not while coasting. This would seem to rule out the transfer case as it is turning anytime the truck is moving, under load or not. When you have it up in the air and engage 4WD do both axles turn? Does the noise occur when you give it a little gas when up in the air? When up in the air with 4 WD engaged, lightly apply the brakes and a little gas. Do you get the noise then? Make sure you are on 4 jack stands and the vehicle is very sercured when doing these things.