short background, f350 7.3 turbo diesel, e4od. had tranny replaced with rebuilt unit 2 years ago. it developed a growling noise when pulling a boat trailer. noise would come and go according to throttle pressure around 60. mechanic that installed it said the planetery gears were going out. it was out of warranty. so i looked for a more reasonable option. found a "good used" tranny with only 15k miles out of a wreck. like the other tranny, operates perfectly when it is just the truck. just towed a boat for the first time since putting in the new tranny and it does the same thing as the previous one!!!! am i missing something here? replaced u joints etc while trying to diagnose the previous tranny troubles. can my luck be so bad as to get 2 in a row with planetery problems?? i am so fustrated with the e4od that i am considering a switch to manual. thanks for any ideas!!

 

Could it be the rearend? Maybe you need new gears.

 

thanks for the reply. guess it is possible. i am thinking of checking the entire driveline before pulling the tranny again. replaced u-joints with the previous one with no change though. pinion was tight. will pull the cover and see if anything shows.
thanks again.

 

 

DOnt rule out the pinion bearing just because its tight. Look at those gears and the wear pattern. SOunds like a rear end problem to me.

 

If the noise occurs at 60 mph it is not the planetaries.

 

thanks for the ideas. i have a few days off over christmas and will check out the rear end then. if you have any other ideas, i am standing by. it really seems funny to me that the growling comes and goes and is only when towing. thanks again for any help.
scott