I know these are really hard to diagnose but any help would be appreciated. I am getting a rumbling noise at speed, at least 45mph when I let off the gas in gear or take it out of gear at speed.

If it is in gear and I let off the gas I hear the noise, as soon as I tap the gas the noise goes away. Just a slight increase in power makes the noise stop. I can not hear it at low speed only on the highway. The best I can tell it is coming from the trans but it is hard to tell.

It is a 6.8 with 5 speed 4x4. I just changed the real axle oil and everything looked good. I changed the transfer case oil and that looked OK also. I have not changed the trans oil yet because I do not have synthetic but the level is OK.

 

I'm thinking throwout bearing going bad.

 

I'm with Johnny....have you checked your bearings/u-joints?

Joe

 

Thanks for the replies. I have checked the U-joints, driveshaft and everything external, that all looks OK. I was thinking it may have something to do with a clutch part since the dealer here changed the clutch a while back.



Sometimes the truck feels like the clutch is slipping. I was not sure if it was just me being paranoid about things because almost everything the dealer did to this truck I have had to fix again. I normally start off in second and if I give it a bit of gas (not too strong but not weak) it feels as if I am slowing letting out the clutch even though it is fully out.



Any other ideas would be great. If it is the throwout bearing what will happen if I continue to drive it? I will not be able to get parts until my trip to the states in Sept. I have an Explorer to drive but need to use this for work, however I don't want to make problems worse.