14 Bolt FF vs. Dana 70

Which one is better and why?

The main reason for picking a 14 bolt is because of the $300 drop in detroit.
The main reason for a dana 70 is better gears choices. A 14 bolt can only go down to 5.13
-- Mike

Seems I remember a drop-in Detroit for the 4-spider D70. Do they exist anymore? Price?

d70's have a weaker pinion. 14 bolt runs a 3rd pinion bearing.

I believe the extra pinion bearing in the 14 bolt is there because the 2 primary pinion bearings are closer together than on a D70. It is there to prevent the pinion from wobbling or deflecting under a load. Not necessarily stronger just a different way to build the same thing.

Don't forget you get 14bff's for $100-$150 all day long. Seems like around here parts are a whole lot easier to find.

To buy a 14 bolt or D70 here is about the same price. Seems that I come accross way more 14 bolts though. I can't see why you would ever need any spare parts besides bearings and seals, so I don't think that the availabilty of spare parts is a big deal since there are Napa stores everywhere. I had a 14 bolt and never had any trouble with it. I wanted deaper gears than 4.56, but when I checked on the price of 5.13's, I just about messed myself. 5.13's for a D70 are about $100 cheaper, and you also have the option of going down to 7.17. As far as all of the price differences go, if you are going to be running a locker and 4.88's or 5.13's, I believe it is about the same price. The both have a huge lip on the bottom that needs to be cut off or you will drag over every rock. The D70 has bigger axle tubes than a 14 bolt, but I don't know what difference that would make.

Have you ever taken the diff cover off either and compared? How about setting up gears? As mentioned - third pinion bearing. There are major loads on the pinion as it tries to walk up or down the ring gear. That extra bearing on the end of the pinion helps relieve the stress on the pinion.

The 14 Bolt is the easiest non dropout axle to set up. Strength is awesome and with some trimming, you can make it somewhat user friendly in rocks.

I've heard the weak link in the 14 is the carrier bearing caps. Since they are drilled and tapped for the retainer bolt, they are a little weak.

To the best of my knowledge the D/L for the 70 only comes with the case now days. I tried to get just the D/L ( with no case ) back in 1994 and was unable to get it by itself. Spicer discontinued the open 4 spider gear case a while back .
Somebody with a conection at Dyneer might be able to get a part # for just the inards and not the whole assy. ?????

I'd just go with a 14 bolt, depending on what transmission and transfer case combo you are running you will be fine only being able to go down to 5.13's. I put a 14 bolt in the back of my rig, I'm only running 36's and some of my friends say "why didn't you just do a 44, because while everyone else clears shit, you'll be dragging it." I just told them that while they're breaking the 44's I'll just be laughing:flipoff2:

14 bolt is the way to go.i think but not sure but the 30 spline axles are a little thicker than the 35 spline axles on a 70 also.the extra pinion berring makes it stronger also.the real low gears like 6.17 are not as strong as 4.56 or 5.13.the lower you go the weeker they get.

The only advantages I can think of are the gearing and locker options.My circumstance I run 5.86s and soon an ARB.:flipoff2:

Originally posted by 73k5tony510
14 bolt is the way to go.i think but not sure but the 30 spline axles are a little thicker than the 35 spline axles on a 70 also.the extra pinion berring makes it stronger also.the real low gears like 6.17 are not as strong as 4.56 or 5.13.the lower you go the weeker they get.

1.5" is 1.5", no matter how you look at it. Yes the lower gear ratio's have a smaller pinion which is weaker. Not much of a problem unless you are running a heavy truck, 44's, and a lot of stupid pedal. The pinion bearing idea was discussed earlier in the thread. I still call B.S. on that one. I don't think it makes a single difference if you have two pinion bearings or ten. You won't have to worry about that.

i would like a 14 for my yota. my friend had to buy a whole truck to get a 70

ok in what did chev use a dana 70?
if the 14 was the best why would they buy dana

Originally posted by mj
ok in what did chev use a dana 70?


wide-side duallies until early 90's

if the 14 was the best why would they buy dana

Don't know. What do you think?

ok in what did chev use a dana 70?

88-91 G30 SRW (14FF also available)
73-91 C30 DRW pickup
77-91 K30 DRW pickup
75-91 G30 DRW
73-93 P30 DRW (14FF also available)
(My info on P30 stops at '93. Probably because the P-series are now produced by Workhorse Custom Chassis. I know I've seen D70 SRW's under their UPS vans ;) )

if the 14 was the best why would they buy dana

My guess is Dana would build an axle for applications where AAM wouldn't.

The Dana 70 came with 4" tubes in the C/K/P-series and 10-lug/disc-brake ends in some on the P-series motorhome chassis. Another D70 bonus is the larger spider gears, providing longer differential life in a wide axle. There's also the option of a good clutch posi (Powr-Lok) when the 14FF is go Detroit, or go home.

Good info U2

4" tubes, holy cow!:eek:

Sure the extra pinion bearing is nice but obviously you have not compared the D70 bearings in size to the 14 bolt. The lower pinion bearing on the 70 is HUGE. Besides they had to run a 3rd support bearing on the 14 bolt because (as stated earlier) the main pinion bearings are very close together (Much like a 9")

both axles are heavy, can be found at PNP easily and had for $100-150 all day, equally as strong. Just base your decision on if you need a selectable locker or gears deeper than 5.13

surprised nobody has said anything about the actual pinion shaft size....
sure, the 3rd bearing is nice, but the real nice thing about the 14bolt is its BIGGER pinion shaft...
D70 pinion shaft 'bout same size as D60....and certainly can be broken......

I can't see why you would ever need any spare parts besides bearings and seals, so I don't think that the availabilty of spare parts is a big deal since there are Napa stores everywhere.
Good luck finding a spare D70 shaft or a napa auto parts on the rubicon or where ever you might brake something. Both axles are solid but I have seen them both brake.


Charlo

Got any pics of the 14b busting?

Or any info on what they guy was running when it broke?

What exactly broke?

...I never heard of anyone busting a 14b..

I have heard of busted 14 bolt and 35 spline D60/D70 axle shafts. Mostly ignorant use of the stupid pedal. Axle shafts are the same diameter.

It was a three mud truck chain all yanking on a buried blazer. He was in the middle with 44s and a 454 :flipoff2: . They must a been going 20 or so when the rope tensioned. He broke a shaft and when the broken shaft backlashed it snapped the other shaft, damn detroits.

Never seen one brake on the rocks :flipoff2:


Charlo

Just to back up the * anything * can break comment.
I think both the Dana 70 and the 14 bolt are GREAT axles , but I have seen them both break.
14 Bolt
Snapped the pinion at the splines - BBC / 465/205 w/ 39.5's welded
Snapped right rear axle shaft - BBF / C6/205 w/ 39.5's welded
Broke ring gear - BBC / 465/205 w/ 38's
Broke ring gear - SBC / 465/205 w/ 32's Wrecker( Tow truck )

Dana 70
Snapped pinion shaft at splines on several trucks
Sheared the Powr-Lok case - BBC/ 465/205 w/44's
Broke ring gear - BBC/465/205 w/44's same truck as above
The Cummins Turbo Diesel crowd breaks Dana 70's and 80's all the time .....

Like what was said before this post , they are both good but anything can be broke with enough traction.
I doubt that a trail truck that is on the rocks would kill either one.
All of the trucks that I described were either worked to death or abused beyond belief.

Don't know if this was posted already, but the first couple years of the 88-up GM used the 70, I have an 89 1 ton that came with the 70. I put a 14FF in cause a Detroit is cheaper, and parts in general are cheaper and easier to get. Not too concerned about deep gears. I already have a set 4:56s that I got next to nothing for. Later on down the road I might put the 70 in, I can get a factory posi or locker for next to nothing.