Metallic Ticking Noise from Transfer Case

[Melason]

Hi, new poster. Could really use some shared knowledge. Sometimes (recently) there is a distinctive metallic noise coming from under my 1996 stock condition Explorer (Control Trac - has 2wd, 4 auto, 4 low). I can hear it starting at about 25 mph, gets faster as speed increases. At 25 mph approxitely 3 ticks a second. It sounds like something hitting the driveline. Similar noise like a playing card in the spokes of a bicycle. Not real loud (maybe as high in volume as someone talking loud?), and easier to hear when driving next to a wall (sound bounces off). Did the coast neutral with engine off test and it was the same (noise was there). It happened first after taking out of 4 low. Occurs in 4 auto and 2wd. The sound does not occur in 4 lo. Sometimes it goes away after turning the engine off, then restarting (immediately, overnight). It was in 2 wd both when the noise was there, and not after restarting. Went away once after putting into 4 lo then back to 4 auto. Warm 80f air temp, and 50F occurred and didn't occur at both those temps. Occurred both when vehicle was warm, and just started in the morning too. Dealer says some metal in transfer case, and wants to sell me a rebuild ($1500+!). I'm thinking since it (sometimes) stopped immediately after turning the vehicle off, it has to do with electronics. Any (good) ideas/similar experience? Thanks much!

 

[Melason]

'96 T-case blown

Answer to ticking noise - bearing broke, gears rotating on aluminum case instead of bearing, almost rubbed through the case. Rebuilt t-case $1500 installed. I saw oil (silver due to aluminum in it), broken bearings, major wear in a few places (shafts supports very worn), and the groove inside of case. Another several hundred miles or less it would have worn through, or maybe exploded (due to bearing race catching on something). Amazing, only a slight noise and not constant.

 

[IZwack]

just curious: which bearing? the back bearing of the front output shaft's?

 

[Melason]

Back bearing in T-case failed

It was the rear bearing that broke apart. The one that sits on the electromechanical clutch. The rear output coupler (yoke?) could be moved up and down maybe 1/8 inch, it was obvious something was wrong. I have 130,000 miles on my Ex, and used the 4wd (front driveshaft) very little so it makes sense the rear failed.

A different shop replaced that rear seal a few months ago. Oops, it probably wasn't the seal that was bad, the oil was most likely leaking around the side of the bearing. I wonder if they even bothered to try and move the coupler, then they might of had a clue the bearing was going or had gone bad.

 

[IZwack]

It was the rear bearing that broke apart. The one that sits on the electromechanical clutch. The rear output coupler (yoke?) could be moved up and down maybe 1/8 inch, it was obvious something was wrong.

if the rear output shaft's bearing failed, i would suggest you look at your driveshaft... an out of balance driveshaft puts cycling stress on the transfer case's bearing which, in time, causes the bearing to become lose.

 

[BeauJ]

1500 for a rebuilt TC???? WOW. That's nuts. You could pick one out of junkyard for a fraction and the install isn't hard at all. I'm still in shock at that price