I just finished driving about 70 miles when I got out of the truck and heard a knocking sound from the tranny. I drove it home and it made no noise at all, and when I pulled into the driveway it made the sound again. It will only do it when I am in neutral and foot off the clutch. When I push the clutch in, the knocking goes away. Fluid level should be o.k., I changed it about a month ago, but it has been leaking a good amount from the vent tube (which I also noticed had a tiny barely visible amount of smoke/steam) coming from it when it was running. Clutch seems strong and it shifts just like it always has. Any thoughts??

 

Might be your throw out bearing,or the input shaft bearing. I would look close at the throw out, because of the way u decribed the knocking. What ever it is stops when u push the clutch down your taking the load of one the bearings that is wor out. When u drop the trans check the input shaft for side to side play and up and down. Good luck tboling

 

How long can I drive on something like that before it goes completely? or is it something that I shouldn't drive on at all...

 

If its the input shaft bearing It could really take your hole trans out. If it were me I would'nt drive no more than I'd have to. Drop the old getrag soon it will save u money in the long run.

 

I would drain and fill the tranny(notising how much matereal is on the magnet) with full sin tynthetic lube, i used mobil-1 full syn.
2nt over fill it by one Quart!!
If there is very little on the magmet(and its a powder not chunks)and you over fill it, the tranny will be happer!





I did this to mine and the noise is allmost non existent!!!

 

Like tboling said, knocking = bad juju. Yank that sucker quick before you start needing more than just a refresh kit. You don't want to have to buy gears.

 

ya, that is NOT a throw out, as a throw out should not be making contact with your foot on the pedal. sounds exactly like mine did when it looked like http://www.turbodieselregister.com/f...hlight=bearing <<<that. i would recommend not driving until you get it fixed. i didn't follow that advice and luckily made it out ok, but it was close.

dave

 

Well after having it brought to the shop (I am not a tranny guy) it appears that it was the input shaft bearing (thanks for all of the help!!) What happened was that since my back-up switch popped out of the tranny, it was blowing oil all over the underside of the truck. Thing leaked like a screen door in submarine. It also appears that I need a new clutch and seals all around. Sooooo...in for a complete rebuild (minus gears, they're still in great shape) including new heavier duty clutch (I told him about my future Bombing plans) to the tune of $1800...again, thanks for all the advice