stronger 8.8 driveshaft or slip??

[CheapThrillB2]

okay in the last three trips out i have busted the rear slip yoke at the joint.
Breaking the ears off the shaft.

wheeled the crap out of the truck and never had any problems. Just assumed the first break was just worn out and it busted. So replaced it with another one that i had and broke that one to.

Now the ujoint cross shafts haven't broke, and the 8.8 flange is undamaged for the most part both times. my pinion angle is good. I really do not have an axle wrap, atleast that i can notice. Does an f150 with an 8.8 have a bigger ujoint and short slip? And by chance does it have the same size and spline slip as the explorer?

 

[Wicked_Sludge]

is your drive line long enough? judging by your pinion angle, your running considerable lift. if the driveline is the stock length, you could be using just the last little bit of the splines which will cause driveline deflection and all kinds of breakage issues...

 

[Evan]

I think the F-150 uses the same size 1350 joint and slip yoke that we have. I don't see how you're breaking that...it's a pretty beefy setup. Todd runs that same shaft, and has never had problems that I know of, and that's with 35x20 tractor tires.

You could go to a larger joint, like a 1410. You'd most likely have to make a custom shaft. But my guess is that you have a problem somewhere...I don't know what it would be though.

1410 vs 1350:

 

[04 EDGE]

seems the slip part of the shaft should be on the trans side.

i wonder if thats causing a problem

 

[Wicked_Sludge]

i think your thinking 2wd, edge. his drivelines facing the right way.

 

[CheapThrillB2]

each break was a different length shaft.....the first one i broke was with the rear axle in its factory location in the frame (position) then the second break was after i stretched the the wheelbase 5"s by moving the rear leaf spring mounting location.

The first time it broke i was climbing a gravel hill that was smooth and was getting after it (rpms). Then this last time i was romping it again on a hill climb but this one was not smooth and was rutted up.

 

[CheapThrillB2]

the rear driveshaft is a front explorer driveshaft

 

[Wicked_Sludge]

ok...so moving your axle further back would only make the problem worse.

it sounds to me like your drivelines arent long enough.

 

[04 EDGE]

i think your thinking 2wd, edge. his drivelines facing the right way.

my 4x4 explorer rear shaft, the slip is up at the trans not at the rear axle.

seems all the newer ford trucks/suv's the slip is always closer to the transmission. maybe the shaft is flexing to much causing u joint failure.

its always at the rear right?

 

[CheapThrillB2]

ok...so moving your axle further back would only make the problem worse.

it sounds to me like your drivelines arent long enough.

okay that made no sense.....................

moving my axle back increased my driveshaft length.

 

[CheapThrillB2]

i can't mount the driveshaft in the other way, the double card. joint won't attach to the pig side of the driveline.

 

[Evan]

i can't mount the driveshaft in the other way, the double card. joint won't attach to the pig side of the driveline.

Plus, that would be incorrect even if you could. You'd have to point your cases way down...lol, as the single joint end is supposed to be near 0 degrees.

 

[Wicked_Sludge]

okay that made no sense.....................

moving my axle back increased my driveshaft length.

moving your axle back stretched the slip yoke out even further. you have a limited amount of travel in the slip yoke. i think whats happening is your combination of lift and rear axle relocation has pulled the slip splines out to the very end of their travel...thus your getting a lot of driveline deflection.

 

[CheapThrillB2]

my driveshafts are custom length.....i know the problem isn't in my slip, i have plenty of engagement at all flex angles.

 

[Wicked_Sludge]

lol, why didnt you just say that to begin with?

here i thought you were running stock length drivelines.