Discussion in 'The Garage' started by MJF, Jul 24, 2002.
Which would be a stronger rear axle. 14BFF or Dana 70?
Not a nickels worth of difference between them. 70 has more splines on shafts 14 has better pinion bearing set up. Both are basically bombproof. If you are going deeper that 5:13 gears for some reason go 70 if not go 14 it is typically cheaper and easier to set the ring and pinion up in.
They are about equal. I will say this though. I had a Dana 80 this weekend and it looked a lot stouter then a 14ff but the guts were not as strong. Yes it blew apart. The axle had 33's on it and was in a Dodge with the cummings diesel. 36,000 miles on the axle and it scattered everywhere. /forums/images/icons/tongue.gif
I abree with Butch on his thoughts here.
The Dana 80 would not be any benefit over a 70 or 14 bolt. Just even more weight and less ground clearace.
yeah, what they said... pretty much a toss up unless you like to trailer your rig everywhere you go and you actually plan on running gears lower than 5.13... for that you'd need a D70. Then again, how many peeps here run 7.xx gears? hard core wheelers who can run anything they want dont go that low... why would anyone?!
I was mainly asking because I have a 70 in a dodge parts truck & was wondering if it would be a good rear for the guys doing the 3/4 ton swap. It seems like it is an option.
What about the spring perch difference between chevy & dodge? Would it need to be moved?
I prefer the 14FF anyday.
Parts are cheaper for it, too.
Plus, when you try to get parts for the D70, there are so many different variations, such as Ford, Dodge, motorhome, 1 ton, etc. the list goes on, its more confusing to get the right parts for the D70.
D70 has several different variations. They go like this:
Those are numbers reason enough to rack your brain. Unless you know which D70 you ACTUALLY have, I'm gonna stick with the 14FF any day. /forums/images/icons/wink.gif
dam, I thought my screen name was at least unique now.
I hope noone mis-ID's you as me /forums/images/icons/grin.gif
more choice of differentials for a 70.
14ff has what
detroit and imitators
detroit and imitators
ARB air locker (cant do that with a 14ff)
I have a dodge 70 under my chev
nverenuf(sorry if it is spelled wrong) also has or is in the process of doing a 70 for his chev, good pics online of the work
MJ how hard was the conversion?
Thanks for the compliment MJ! I'm proud of my 70HD! I also like the D70 for it's wide variety of ratios.
Initially, the 14 bolt looks stronger because of the extra pinion bearing, but it's actually there because the 2 big bearings are closer together (than on a D70). Without the "pilot" the pinion would wobble, nothing wrong with the design just a different way to do the same thing. Both the pinion and carrier bearings on a D70 tend to be a littler bigger than on a 14 bolt (a D70HD is considerably bigger).
The D70 can be confusing due to so many models but if you know for sure what it came out of it's no worse than a 14 bolt.
if anyone here has a D70 and uses gears lower than 5.13s give us a "hell yeah!!!"...
<listens... nothing... dead silence>
i rest my case, put in a ff14b and ROLL. /forums/images/icons/laugh.gif
Hold it! Here we go....Hell Yeah!!
Ok, mine isn't in my truck yet but I'm building a Dana 70HD for my truck with 5.86's (see my web site link below). I may eventually go to a 7.17's, Why? Why not! Many people act as if ratios bigger than 5.13 are not driveable but actually they're not bad to drive at all. I've got a friend with 6.17's in a truck with 39's, it is very interstate friendly. Again, why not!
Why do some people go to a 39"+ tire, simply because they can!
If I need lowwer gears than 5.13, then I going with 2.5 ton axles.
Me too! /forums/images/icons/wink.gif
Yeah but rockwell's are just too freakin' heavy /forums/images/icons/blush.gif
If you want to go lower than 5.13 and be bombproof go rip a dana 135 out of a f /forums/images/icons/shocked.gif rd F550, that 13.5" ring gear is gonna be hard to break.
Actually, the Rockwells are not that much more than the D60 front axles. Somewhere in the range of within 75 to 100 lbs. of each other.
<font color="green"> I believe that that is only true if you convert them to the pinion mounted disc, but I may be wrong. I was offered a pair last year for $100, but I had nowhere to store them and they would have required me to lift the truck like 10" higher than it is now because of the 3rd member being so high. They are truly massive axles... </font color>
you have to narrow them and figure out a braking method.
also have yet to hear anyone really comment on the handling they offer.
for me it was easy, I paid a shop to do the axles.
pre internet and my first truck, so I didnt go near the axles.
I did have Rieder Racing send me new 4.88s and detroit for that deep ratio, which required me to also buy a set of 35 spline Dana shafts as the Dodge had 32 splines and the 32 spline detroit was only good to 4.56
I was convinced that 4.88s would be that much better then 4.56s, what a moron.
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