100dollarbill

hey what up guys,

i've got this lil concern about my truck, its a stock truck with 31's on it, when i drive it on the highway, when i shift into 5th gear, i hear a noticeable humming noise, not loud but you can hear it, no power is lost, but the more i step on it the more it wants to be louder, i asked a friend of mine who's' a mechanic, says it might be the throw out bearing. is this true? :pat:

Flamedx4

I bet its the retainer and bearing on the shaft that 5th gear is on. At a lower speed put it in 4th and step on it. Pick as low a speed as you can without making the engine ping badly. Listen for the noise. If it's not there, your mainshaft output bearing is fine, so that leaves the bearings on the 5th gear shaft. The 5thgear shaft has a nice heavy bearing in the case at one end, but the other end just kinda hangs out in space with a sort of bracket to support it - not very strong. They get worn out by people who don't have enough sense to downshift any time there's a load in 5th (like going up hills.) Anyway I'm just guessing, without hearing it who knows?...

100dollarbill

in 4th gear i can go as high as 70mph i wont push any more, u dont hear no noise when fourth, but as soon as i put it in 5th it starts doing that noise, more of a humming noise like i said, while in 5th gear when driving if i let go of the gas pedal the noisie goes away but once i give it gas its there again. when i get to the shop i'll go under there see if i can find something. im not exactly a mechanic though....

Flamedx4

Try all the lower gears, do it at a lower speed than you normally would use that gear in, and get on the gas. This really loads up the bearings in the transmission. In any gear but 4th the noise would be apparent if your trans is due for rebuild. In 5th though, its a special case, as I detailed above. There is nothing to see, it's all inside. You could just have a bad bearing or syncro on the fifth gear shaft.

100dollarbill

i did all what you mentioned, no funny noises no nothing, just when i get on the highway start hearing it, its kinda of annoying, we'll see what happens, i'll probably look around for a tranny to keep around just in case anything bad happens down the road. i also looked underneath of my truck, i noticed junkyard markings on the tranny, rear and front differential, looks like they been replaced, it doesnt make sense in a way since the truck i got it with 114k now it has 117k.