Ford 9"
 

Anybody have any thought on a 9 inch taking the abuse of a diesel? Now Im talking about on a grocery getter/ drag truck, no sled pulling. I really want to get this d70 out of my truck, the pinion is weak and its a open diff and I dont feel like putting any money into it just to see it break. IIRC Gerg's Project X ran one with success, and he claimed it was almost at 1000hp and his truck would be heavier than mine, which is a 95 reg. cab, long bed, and hopefully with the fuel and twin turbos Ill be 700-800hp.

One reason Im thinking this route. b/c they are a dime a dozen and the aftermarket is better for the 9" than any other axle. I really wanted to go w/ a 14bolt, but with the gears it has compared to my front d60 is a 3.73, which IMO is going backwards, and would require a front gear change which would be $$$.

I was thinking if I did go that route a big bearing 9" w/ 35 spline axles and either a detroit or a spool?

I know the d80 is an option, but its heavy and everything about it is expensive.

If you think the d-70 pinion is weak, you need to see a 9" next to it.

Why would you want to go to a rear that is going to consume more power to turn? ? ?
If you said you are going to road race your truck and needed to be changing gears all the time, i could understand the need for having a 9".....

But to go to a 9" that takes more power to turn and because of a strength issue, i would take a D-60 over a 9" as for strength...

Rears only break from bad drivers anyway.

Im guessing you havent either b/c not only is the pinion bigger it also has a 3rd bearing, and the extra 10hp it takes to turn is a mute point.

I have been told by Moser, Strange and Mark Williams that they will not hold up due to the placement of the pinion on the ring gear. What they told me was since the pinion sets low on the ring gear it pushes away under load and would break the ring and pinion. However Curry says they can make one to hold up but it's $8000.00:umno:

Gabby run ford 9" front and rear axles on his truck and it has run in the 9 sec range so i believe that they will hold up to the abuse

His are the curry axles I was talking about.

I looked into using one for my mainly street driven truck and I decided against it. Anything over 31 spline and you have to run a locker, ARB has an air locker for the 35 spline but from everything I have read about it on the net says it has a couple design flaws that make it weak ( really expected better from arb). I think for a 700+hp diesel you would want some 40 spline axles and a light weight vehicle to make it live long.

I chose to go with a 9.5" 14 bolt and eliminated the c clips with a set of ford big bearing housing ends and custom axles, I have less than $1K in the entire axle with a tru track, moser axles and disc brakes complete but its in my little 3900 pound truck with a diesel.

So what if you go with a high pinion then?

14b is a viable option as far as aftermarket support, and I think that the weight over the rear tires would benefit traction... though you are 4wd so that may be a lesser issue

Your right, but the only problem is gear matching, here isnt a 3.55 gear for the 14bff.

Project X did run a Ford 9" built by Charlie Stewart (817 253 5796).
I don't know about how they would work in these trucks, but every race car my father has ever built, has a 9" under it. We're currently in the process of ordering the parts to build a 9" to go under my s-10.

If I go this route I was planning on getting a big bearing one out of a truck w/ 35 spline axles.

I say it will be hard to break the dana 70 with 700-800hp while drag racing. A 14 bolt or dana 80 is only going to add weight and a 9" is going to require a decent amount of money to build it strong enough. My vote is to keep the 70 and weld the spiders.

I might try this and if it breaks it breaks, I guess everything bad I here about it is from the pullers and not the racers.

I have a 9" in the vette, but I have replaced and upgraded everything to eliminate destruction if at all possible. A 9" still weighs less than a 70 and an 80 even if it costs more to build.

Don't know, I thought the high pinions were weaker than the standard 9".

We currently have well over 1500 hp and have never hurt our dana 70.

The new design ARBs are a POS. I'd never consider them as an option, unless the issues are fixed with them. They'll never get fixed though, because ARB says there isn't anything wrong with their design.

It just moves the breaking point to the other member of the R+P.

That's not what he was talking about.


I would consider running a 9" rear in a light vehicle, but not in this app. If I were to build an axle for this app, I think I would retain the d70. You might consider doing a SF d70 to save a bit of weight if that is a concern.

Guessing i haven't what ! ? ....seen that a 9" NEEDS the other bearing from the poor design of the extremely close 2 pinion bearing being on top of each other....
What else do you think i haven't seen..... I bet you think that's a great design...



I build rears, im telling you, the 9" is not stronger then the D-60, let alone the D-70... The 9" isn't much lighter then the D-60
The D-70's only issues is the cross bar in the spider assembly...so you can do 2 things, a spool for the 70 or a detroit

Saying the hp loss is a mute point....is incredibly INSANE, any hp loss in a performance vehicle is not a moot point....years ago we dyoned 4 rears, and the 9" was more than 10hp loss, (im going to try and find that) and you don't want to lose any HP in the driveline in any vehicle, let alone a heavy one.


AS for the high pin 9", you are now racing on the coast side of a ring gear, not a good idea at all...


Everyone runs a 9" for the story of there is more available... and everyone that says that, doesn't change there gear ratios like they should if that is what there worried about...

Many rears are stronger and don't soak up as much hp......

Which ARB's are you referring to? I have one that is about 4 or 5 years old, and the gear sets are the same. When did they change?