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So I am in the market for a wider rearend and my bugdet has gotten pretty tight. I have a very nice 35 spline 3rd that i built for my current rear end and have found a nice currie f9 that fits my needs but it has 40 spline axles. What are your opinions?

a. Get a 40 spline spool and rebuild my 3rd?

b. Get new 35 spline axles and try and sell the 40s?

c. Sell my whole 3rd and build/buy a new one?

d. Just let this one sell to someone else and wait for another deal/ buy one new?

I remember reading some where that the bearings are different on the 40 spline and less desirable for offroad. Just curious what the concensus is.

get a 40 spline spool. i think wiliams makes one that fits the case you should have

I've had a 35 spline floater under my yellow bronco play truck for years, used very very hard with 35" tires and big engine. I keep expecting it to break at which time I will upgrade to 40 spline but it's lasted so long now, that I think it was worth the cost savings to run 35 instead of 40 spline. I have 35 splines because I started out with a 31 spline semi floater 9". Then the axles broke and almost killed me when the wheel departed on a mountain road in baja. I had some 35 spline semi floaters left over from the stock full so I replaced the 31 spline detroit locker with a 35 spline spool (good riddance to the detroit locker, the spool is way better on the street). Then my 9" housing was used up with cracks on the tubes and cracks on the stud ring. So I bought a tube works full floater housing but just bought 35 spline floater axles since I had a 35 spline third member. At least with the floater if you break an axle you can drive it home, down from 4 wheel drive to 3 wheel drive so taking a chance on 35 splines with a floater is ok to me.

For the race bronco we started out with 40 spline. Never even considered 35 spline since we were buying everything new.

baja-chris wrote:I've had a 35 spline floater under my yellow bronco play truck for years, used very very hard with 35" tires and big engine. I keep expecting it to break at which time I will upgrade to 40 spline but it's lasted so long now, that I think it was worth the cost savings to run 35 instead of 40 spline. I have 35 splines because I started out with a 31 spline semi floater 9". Then the axles broke and almost killed me when the wheel departed on a mountain road in baja. I had some 35 spline semi floaters left over from the stock full so I replaced the 31 spline detroit locker with a 35 spline spool (good riddance to the detroit locker, the spool is way better on the street). Then my 9" housing was used up with cracks on the tubes and cracks on the stud ring. So I bought a tube works full floater housing but just bought 35 spline floater axles since I had a 35 spline third member. At least with the floater if you break an axle you can drive it home, down from 4 wheel drive to 3 wheel drive so taking a chance on 35 splines with a floater is ok to me.

For the race bronco we started out with 40 spline. Never even considered 35 spline since we were buying everything new.

Chris, you race stock full with Ramsey right? I have a set of those stock full axles in my current set up but I need to go wider.

Anybody hear anything about the bearing on a Semi float 40 spline I hear they ar ok for drag racing but the lateral laod of offroad is no good?

If I get a new spool do I have to get another overhaul kit to install it? I have not even put oin in my rearenf yet I would hate to buy a whole new install kit.

a. Get a 40 spline spool and rebuild my 3rd? this is what I would do if you have all the parts as long as the case is 3.25

b. Get new 35 spline axles and try and sell the 40s? this will be hard unless you know someone that has the same spec housing....spool would be cheaper then axles

c. Sell my whole 3rd and build/buy a new one? used case go for pretty good money but not needed unless you want to change your gears as well as spool or you just want new stuff

d. Just let this one sell to someone else and wait for another deal/ buy one new? good if you can hold off or have the cash for new parts

I remember reading some where that the bearings are different on the 40 spline and less desirable for offroad. Just curious what the concensus is.

My 2 cents....hah

35 spline inner since not many(none) diffs come in 40 spline
40 spline at drive plates....thats what I did.

I didnt want a spool since its obnoxious.

tell currie to make the axles that way if the rear end comes with axles it shouldnt be an issue.

TCS now PPM Ryan made my axles...pro am can make them, summers bros, cone, etc....

If you have a 35 spline setup already, it should have the 3.25 bearings in the center section that you will need for the 40 spline spool. A new spool is going to be cheaper than a pair of axles (unless you can get them free). The Mark Williams spool has the splines all the way from one side to the other, other spools do not. This is important if your axles and housing don't exactly line up with the splined portion of your spool (when axles come from another project). The spline pressure angles differ between some axles and some spools, see the MW website for info on this. You don't need a new kit (bearings) to swap spools, but you will need the correct bearing puller to get them off the existing spool. Never had a problem with the carrier bearings in a 9" be it 35, 40 or other spline.

one more thing make sure you get the correct spline spool for the axles you are getting with the housing. Ask kiefer I found out the hard way hah

I think Mark Williams uses a different pressure angle then more of the common stuff...do your homework!

Im just gonna see if the guy will seperate and sell just the housing. Not likely but worth the try.

shockseals.com wrote:I think Mark Williams uses a different pressure angle then more of the common stuff...do your homework!

I learned this the first time though this. Mark Williams axles are different so he has spool for both. I had to do this home work for my 35 spline set up. I have a MW case and spool with currie axles in my current set up.

Option D. Get something more practical that suits your budget and needs.

cs_drums wrote:So I am in the market for a wider rearend and my bugdet has gotten pretty tight. I have a very nice 35 spline 3rd that i built for my current rear end and have found a nice currie f9 that fits my needs but it has 40 spline axles. What are your opinions?

a. Get a 40 spline spool and rebuild my 3rd?

b. Get new 35 spline axles and try and sell the 40s?

c. Sell my whole 3rd and build/buy a new one?

d. Just let this one sell to someone else and wait for another deal/ buy one new?

I remember reading some where that the bearings are different on the 40 spline and less desirable for offroad. Just curious what the concensus is.

Why not take your axle to currie, and ask about havingnew tubes that re wider welded in... they offer a "re-tube service". You could likely uy new 35 spline axles of the correct length, and keep your existing housings and call it done.

AussieRod wrote:Option D. Get something more practical that suits your budget and needs.

Yeah probly just let this one go.

tcm glx wrote:
Why not take your axle to currie, and ask about havingnew tubes that re wider welded in... they offer a "re-tube service". You could likely uy new 35 spline axles of the correct length, and keep your existing housings and call it done.

Can they re-tube a rearend that has been trussed?

they'd either have to cut the truss off or just add to the tubes beyond the end. Either way it's kind of a pain and probably not the greatest way to go about it.

Here's a 9" my buddies did a while back. Was originally narrow & going in an exploder & then got widened to go in a k5 blazer. If you look closely you can see where the original truss & tubes ended & where they added the width.