i have a 92 ford f350 welding rig with a 7.3 idi E4OD.my truck makes a noise on the upshift between 3rd and 4th and again between 4th and od and when pulling up inclines.the noise makes a bad u- joint type noise and sounds like its coming from the driveshaft area.all the u-joints have been replaced,there is no play in the driveshaft,all bolts are tight at joint retainers,trans mount has been checked and tightened,the pinion to yoke nut is tight i couldnt get it tighter with a 1/2 breaker bar.I thought maybe it was a bent driveshaft so i took a known good shaft off my 96 f350 and tried it and it still did the same thing. i jacked the truck up and ran it through the gears and the noise wasent there,so its an under load problem,as its making the noise i notice a vibration through the seat and floorboard area and my speedo vibrates a little. and i also replaced the rearend a couple weeks ago,i spun the bearings. the last diagnostic step i took was pull the vss and look for shavings and there were none,any suggestions i am plumb out of ideas.also i cannot tell for sure if the noise is in the front or rear.my wife thinks i put to much on the truck so ive taken everything off except the built bed it weighs about 650-750 lbs and the noise is still present .i am worried about putting my equipment back on the truck till i get this problem fixed.but no equipment means no money

 

Put it up on jackstands, apply a little Emergency brake and run it through the gears see if you can reproduce it. If you can then you got a better shot at finding exactly where its coming from, if you can't then it (big guess) might be axel bearing related???

Thats all I got, Good Luck

 

i tried that already.it only happens under load.i am going to try and rotate the driveshaft 180 deg.and see if that will help

 

Good Idea on the driveshaft. My bro in law's dodge dakota 94, had that problem. we put the driveshaft on without marking it. It vibrated the truck in each gear really bad, (automatic) but it seemed to be consistent all the way through, especially w/ higher gears, rpm as expected. Sounds like you have tried alot of common deductions to figure the problem. As with a 1-ton it probally has more to it, hanger bearing, etc. Hope its not internal tranny gear related. Good luck.

 

It sounds like you may have some clutch chatter. Considering the weight of a welding rig, I suspect the clutch packs are trying to slip during thos shifts. The higher gears are under more strain than the lower ones. Did it first start with the shift to O/D, then work it's way to the next lower shift. I'll bet sooner or later it will be between all shifts. I would first check the line pressure to be sure the clutches are getting all the clamping pressure they are suppossed to. Then drop the pan and look at the trash thats in there. Maybe even carry the pan to a transmission shop and let them look at it. Good luck.

 

i hope its not in the tranny i have less than 10k on it since rebuilt including a new TC.the trnny fluid is good and red and filled proper,and if the cluthes were slipping it would set a code right

 

I don't know if it would show a code or not. If it was re-built recently, I would take it back and have it checked. Especially the line pressure. Let them hear the problem. Good luck.

 

well i found the tranny was a quart low,after i put that quart in the noise was still there but if i eased into the shift points the noise was barely audible.so i believe now the problem could be the tranny.the codes my truck set were 23 tps but its done that since ive owned the truck and its been replaced and set many times.the other code was VSS which has been replaced a bunch of time and pulled and cleaned a billion times.no tranny codes though