hi my name is kyle just joined and am proud to own my ford truck. I just bought my first truck a 1991 f150 lariat extended cab short bed with the 5.0L in it, 4x4 of course. however i have run into a problem. I usually fix everything myself, its just cheaper and im more confident in my work than others. However, i am not sure what this problem is and was wondering if anyone else could help. I was driving my truck to work yesterday and when i stood on it to pass someone it sounded like i was grinding to plastic gears against each other. Now when i was in low rpms (2000-2500) it would go through every gear fine but when i was in 3rd at low rpm and i stood on it, it down shifted to second and shot the rpms up and that when the grinding sound came back soon as i dropped the rpms back down to about 2000 the truck seemed to kind of grab and things when on as usual. It does this when downshifting from any gear. I think it may be the torque converter not sure, it has the E4OD tranny, and a borg warner 1356 manual shift, any help is appreciated and i still will always be true to the blue oval.

 

Have you checked the left/driver side Motor Mount?

If the engine is raising up when you get on it,
the fan could be hitting the radiator shroud.

May or may not be the motor mount, just a thought...

 

i would look at what 1987 said with the motor mounts then i would check the simple things first like motor,trans mounts bell housing bolts trust me heard of weirder things then start looking at the harder things and come back to this forum from time to time keeping us posted remember two heads are better than one.

 

Hi, I had a similar problem. When taking off at a green light, if I hit the gas too hard, which I love doing. LOL ! The motor would jump up causing the fan to hit the shroud. Simple one man motor mount test : 1. Raise hood up. 2. Start engine. 3. Hold brake hard. 4. Place gear selector in Drive. 5. Keeping left foot holding brake hard, raise R.P.M.'s while watching through the windshield and see if the motor raises up and causes the noise. If the motor lifts up a lot, you have a broken left side motor mount. You can put the selector in reverse and test the passenger side as well. My two mounts were split in half ! Only thing holding them together was the thru bolt in each mount. I changed both mounts as well as the trans. mount. Made a nice big difference ! Good luck ! P.S. make sure no one is standing in front of vehicle when performing this test !.....Ernie

 

ok ill try that today thats an easy start ill let you know tonight how it goes.

 

you can always pry on em with a crow bar. check your trans mount too

 

ok i looked at all the bolts they were tight and none of the mounts looked cracked or stressed at all. I proceeded to taking the bottom pan off the tranny and found the bolts holding it on were loose but tight enough where it stayed on. when i took it off i found that the magnet inside had collected a ton of very small metal shavings im gonna try and drop the tranny and the torque converter in the next few days. and by the way the truck didn't make the grinding sound when it was in park and i revved it really high to like 4000 rpms. the transmission had been rebuilt by a shop 20,000 miles ago but its too soon for that to be bad but you never know im thinking they may have messed up on the rebuild. ill keep you guys posted as i go along the way.

 

4000 rpms isnt REALLY high, but thats besides the point. looking at them, they wont look busted, pry on it, or even put a block of wood under the oil pan and jack it up, then you might see seperation. if its not making the noise in park, the torque wont twist anything in park. theres always a lot of metal shavings on the magnet. before you drop the trans, try getting the engine to move. or even look at the fan shroud and see if it looks worn away or broken where the fan could hit it.

 

ok i took a look at and around the fan and the shroud and i didn't see an markings where they may have come in contact with anything.

 

Did you put it in DRIVE and nail the gas with the brake held?