I was wondering if someone knows if anyone makes a limited slip replacement/conversion for a 9" with 3.50 gears? I have to engage my 4wd just to leave an intersection with snowy roads.

 

The 9" ford is the most supported differential in automotive history. So basically everyone makes a limited slip or locker for it.

 

I checked Bronco Graveyard, but nothing for a 3.50, only 3.54 and up. Where should I look?

 

there is no carrier split on a ford 9"

 

I'm not sure I understand that last post...

 

A Ford 9" uses the same carrier or in this case the tracloc for all gear ratios it doesn't make a difference if it's 2.75 or 6.50 gears.

 

Only the D44 axle uses the split carrier and I don't think the split is the 3.54. I think it starts around 3.73 and upfor one carrier and below for another.

But as monsterbaby has pointed out there is no carrier break for the 9 inch axle.

 

Okay, so how do I know if I have a 28 or 31 spline diff without pulling an axle? And...how difficult is it to add a trac-lok in?

 

If im understanding right...its an open diff? If you wouldnt mind having the rearend locked, buy a minispool for like 60 bucks. Easy to do. You would have to pull the axle shaft first though and count the slpines, like stated above.

 

Correct me if I am wrong, the 3.50 9" came in the 80s (ex: full sized broncos). A 1979 truck would have the 3.54. As people pointed out, no case difference.

As for splines, it is pretty simple.

Remove the wheel, remove the four nuts (usually 3/4" and you can use your lugnut wrench) holding the retainer plate, and pull the axle out. Once I get the axle part way out, I put a nut back on to keep the backing plate from coming off.

If the axle appears "stuck" sometimes you will need to use a slide hammer to remove the axle. BUT, I have never had to do this on a older truck, usually rotating one or both tires with the rear housing jacked up and both wheels off the ground will let you slide it out. Reason for having both sides jacked up is the housing does not deflect and this makes getting the axle out easier.

Just lift the axle out straight so you do nothog out the inner seals with the axle or its splines.

It is not that tough or time consuming. You will want a rag so you do not drip fluid all over the place. It does not hurt to have the side you are working on slightly higher so the fluid flows to the pumpkin.

 

OK, I will. Ford didn't switch ratios from 1979 to 1980. You could find 3.50 gears in almost any 4x4 with a 9" regardless of year. Ford didn't use 3.54 gears in a 9" to my knowledge - but I could be wrong about that.

The only for *sure* way to check the splines is to pull the axles and count the splines like rebo says. Almost all trucks got 31 spline axles.

Don't buy a minispool. You want a limited slip. Like Rob (monsterbaby) says, everybody and their mother makes some sort of traction aid for a Ford 9".

 

My 1979 150 had 3.50 in it.

 

There is no such thing as a 3.54 for a 9 inch axle. If you have an 8.8 rear axle then thats another story but not in a 9 inch. The front D44 axle would be a 3.54. There is always a slight difference beteen the front ratio and the rear ratio.

In and around 84 ford started to use the 8.8 and the 9 inch axles in the F150 trucks. About 86 they all should be 8.8 axles in the rear. From about 77 or 78 I would safely say that all the F150 trucks are 31 spline axles. I've seen 28 and 31 spline axles in vans which is a good place to look for a good used trac loc.

 

Are you sure about no 3:54 9 inch drop outs? The rear end came out in the 1957 model year..and over the years I seem to recall the following ratios: 257; 273; 300; 331; 354; 373; 411; 456; 511. Some of these ratios were only available in the Muscle parts catalog.

I'm not doubting you...it's been a while since I looked up parts for a 9 inch.

btw...the 8.7 was introduced in model year 1967.

Maybe I'm thinking of an 8" 3:54?

 

I have never seen nor heard of a 3.54 9 inch ratio. I guees that doesn't mean there isn't one but I have been around some older guys that have taught me the things I know so I kind of rely on them and the net for my info.