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If I can only make one mistake a day. I consider it a success !!! ? ?Well, shit.
It seems my first post in this thread was wrong. I’m sorry for any confusion I caused.
6.7 450's use the 4.30 ratio but it's only in the M300 differential.Uuuggg, my head hurts! ?
Edit: BTW, I'm totally convinced this problem is 100% related to the high torque output of the 6.7 engine, and exacerbated by the 3.55 gears unique to those trucks. This set of parameters likely produces an excessive amount of twist in the axle tube between the differential and the hubs. With the tires planted firmly and accelerating hard, the weak link is revealed at the spring saddle plate connection on the axle. With substantial weight loaded on the springs from say a goose neck trailer, the springs are holding the mounting plate firmly in the plain of the springs and the axle tubes likely twist at the welds on the saddle plates, eventually fracturing the wall of the axle tubes.
I'm not completely sure the 3.55 gears make this worse, but again they are unique in these trucks to the 6.7 engine. It is possible that 4.30 gears in a 6.7 truck may even make the problem worse. If there are Super Duties being built with 6.7 engines and 4.30 gears this will become evident if it's a problem.
Ya, different axil on the heavier trucks. Again I'm not sure if the 3.55 gears are part of the problem or not, just that they are specified with the 6.7 in the 250 and 350 Tremors and for now the problem is limited to the diesels. Clearly the torque applied to the rear axil is high enough with this engine that it's twisting the axil housing tube enough to fatigue the welds at the spring saddle bracket.6.7 450's use the 4.30 ratio but it's only in the M300 differential.
Well, I've already towed about 7500 miles this year out of my 10k I have on my truck. Haven't noticed any issues, yet.
Jeep on bumper hitch car trailer, I'm not pushing the limits at all.A camping trailer I presume?
I’m more concerned for the agricultural use case. Very dynamic tongue weights, not to mention legal allowance to overload.
Never imagined I’d have to worry about crushing an axle, of all things, in a Super Duty. And that Ford would just shrug at the problem!
Mine had that at 6 miles. I think it’s from lining it up on the chassis.One theory is that paint flaking off the axle in that location is indicative of axle tube flex. Well - I have some flakes and they are only showing up under or very near the perches. Sounds legit, but the coatings are shit anyway you look at it, so who knows….View attachment 29244View attachment 29245
Same. Ever since I’ve had the truck with 3 miles on it.Mine had that at 6 miles. I think it’s from lining it up on the chassis.
It IS true...all Tremors are the same except for the 7.3 has a 2.5 inch hitch reciever and different front springs......that is it!It is my understanding that no, the axles on a 7.3L and 6.7L are not the exact same. The whole F250 Tremor is the exact same as a F350 is not true. Only an F250 Diesel Tremor has the same rear as an F350.
There is a thread, on these forums, that includes a video outlining the specifics. I believed they were the same as well, but it is not true.
yup your right....my bad 4.30 gears...but same axle/diff3.55 vs 4.30 rear end
It's possible. Mine had the missing paint when I brought it home (~8 miles on the ODO). I suppose the paint could flake off if the tubing became deformed when the nuts on the U-Bolts were being torqued down. Someone could verify this if the axle was unfastened for some reason (maybe when a lift kit was being installed?).One theory is that paint flaking off the axle in that location is indicative of axle tube flex. Well - I have some flakes and they are only showing up under or very near the perches. Sounds legit, but the coatings are shit anyway you look at it, so who knows….View attachment 29244View attachment 29245
It IS true...all Tremors are the same except for the 7.3 has a 2.5 inch hitch reciever and different front springs......that is it!
Capeesh!
Why does the 7.3 F350 have a rear gross axle rating of 6950lbs while the 6.7 F350 has a rear gross axle rating of 6830lbs?