OK. my buddy "had" a 2003 F250 4X4 with the 5.4. We have been building a long travel dune buggy in my garage since october of 2006. we got it done and we bought a 35 foot gear box toy hauler. we've got the whole set up for towing like the load distribution bars and a sway bar(its not a 5th wheel) anyways we took it up to silver lake sand dunes in MI about a month ago, and on the way up there the trans temp gauge on the dash kept maxing out. so we kept stopping to cool it down. When we made it up there we unhooked the toy hauler and went to go drive around town and there was a loud ticking sound coming from the trans right around where the tourque converter is. The truck ran good but there was just a ticking coming from the trans. We had fun on the dunes with the buggy, then on the way back from the dunes we got about 2 hours when the trans temp maxed out again and then we saw smoke coming up from the hood. So we pulled over and called on of our friends to bring there F350 deisel to come pick us up and tow the trailer home. So we make it home and the next day he takes the truck to work with out a trailer and the truck just stopped moving. The motor was running but it wouldnt go anywhere. He tryed to start it buy it was just making a horrible growling noise. So i took the trans off the motor and saw that the flex plate had cracked in a circle around all 8 bolts, so the starter was just spinning the outer part but not the crank. So i replaced that and the truck ran fine. then about a week later the smoke came back. So i looked at it again and the rear main seal was pouring oil out. so when i took the flexplate off to replace it, I noticed that the new flexplate was already starting to crack. so i replaced the seal and the new flexplate. The next day he drove down to chicago and traded that in for an 06 F350 Dually with the 6.0 Diesel. on the way down to chicago the rear main seal go chewed up again and it was pouring(seriously pouring) out onto the exhaust pipes. NOW....what would have caused all this stuff to keep breaking after we towed a trailer with it????.....Also doesnt the 06 F350 have the 4r100 Trans??

 

You SMOKED that transmission. The temp gauge on the dash is nothing more than an idiot light with a needle. When it hit the red, the damage was already done long ago. That, combined with the fact that you kept driving it (and towing), means that it will need to be rebuilt. Was he towing the trailer with the F-350 when the seal went out? Also, the 06 F-2/350s have the Torqshift 5r100 (or is it 5r110?).

 

So lets see here.........



First you see this happening

Then we move onto this sypmtom

I mean holy hell, wasn't it obvious by now?

You're kidding right?

Dude......no fawking way. Seriously?!?!?!?!


Then this question gets asked.



Now I mean by your own statement (true?) you're good enough to pull a transmission out and change a broken flex plate, but you couldn't put 2 and 2 together when you SUPER heated the trans multiple times that maybe just MAYBE it was gonna die? When you replaced the main seal wasn't the condition of the trans oil just a tad odd? I know what fluid thats been heated repeatedly like that is like and you can't possibly mistake it for fresh oil. I can guarantee that you all but welded portions of the trans internals together creating all this extra drag causing super high torque loads on the flex plate making it break. If not that, what little oil is left is most likely turned to the consistancy of varnish and not alowing things to move. The redline on the factory idiot gauge (guess it failed in this case ) is around 300* give or take. You start doing damage to the trans by around 250*. This means that by the time you're reading hot on the in dash guage the trans is about medium to well done after the first time. You apparently were going for charcol briquette.


Anyways, the best thing to do on any truck that MIGHT tow in its life is to get a trans temp guage so you can see WTF is going on. And for Gods sake, if it keeps getting hot like that then stop towing until you can get the issue fixed. Additionally as soon as the fluid temps reach 250* it has reached its breakdown point which means the fluid has sustained damage and can't function as intended anymore. It would need to be flushed ASAP or damage will occur as its used for both lubrication and a friction agent for the clutches and torque converter. I'm guessing that the combo of the 5.4L (low power) and auto trying to pull a 12k load was causing the trans to hunt gears which builds up alot of heat. If more cooling is needed an aux cooler from a 6.0L is the next thing to add.


The 4R100 went away in 04 I believe. In 05, or there abouts, it was dropped in favor of the 5R110 (Torqueshift) in all models. The diesels quit using the 4R100 back in mid year 03.

 

ok, first of all it was my buddys truck and yes i am good enough to pull the trans out and change a flex plate. anyways....I was following him up to silver lake, i was behind him in my F150. He told me this all happened when we got up there. I did drain and flush the fluid when we got home, when i changed the first broken flexplate. My buddy was the one who didnt pay attention to the temp gauge on the dash. I dont have to worry about the problem anymore because he traded it in for 15900. and he got a 06 350 6.0 so i dont have to deal with that truck anymore, but i just wanted to know what would cause the simultaniously cracking flexplates and the chewing up of the rear main. Everyone tells me its a bent crank....Does this sound logical to you guys?

 

A bent Crank would have tons of noise in the motor...

Cracked Flexplates and Rear mains can be caused from extreme convertor heat.... Ding Ding....

 

I doubt he created enough heat in the trans to remotely warp the crank. Besides you'd see all kinds of heat discoloration on the torque converter, flex plate, and crank, or did you miss that? The only way to find out would have been to remove the flex plate and manually turn over the engine with a dial indicator on the crank shaft to check the runout. I doubt you'd see any as the trans had major issues most likely causing the problem. As I stated the internals of the trans were probably close to a solid mass of garbage due to the gross overheating and neglect is sustained. All that caused very high stress loads on the flex plate which is what failed first. Thats usually one of the weaker links as the bolts are grade 10.9 as I recall. Though I'll bet if you had the input shaft inspected you'd find signs of twisting as well. Regardless these high stress loads most likely caused vibrations or torque spikes which will eat seals. I feel sorry for the dealership that got duped into taking on that basket case of a truck.

 

Took the words right out of my mouth... I feel sorry for the next buyer also. I know it is just another truck out of the thousands out there, but I would feel bad about even trading it in and saddling someone else with that.