Narrowing a truck ford 9 inch rear end

[ogasman]

I have a nice rear that I am going to narrow and run in a 55 T-Bird.  Problem is that I want to change to the 4 1/2 wheel bolt pattern from the truck 5 1/2.  The axles are a nice set with 31 splines.  There is enough meat to have them shortened and re-drilled to the 4 1/2 wheel bolt pattern.  Question is are there a set of drums that will work with what I am trying to do?  Anything off the shelf that will have all the dimensions of the truck drum with the 4 1/2 bolt pattern?  I can get a set of truck drums and have them re-drilled, but that is getting cost prohibitive.

Thanks
Paul

[gdaddy01]

I would think it would be a lot cheaper to drill the drums after drilling the axles . should not be that difficult .

[BattlestarGalactic]

I have 4 1/2" pattern on the back of my '69 F100.  I run Moser 35 spline axles(did have stock 31 spline redrilled), have your stock axles redrilled to 4 1/2".  I just redrilled the drums to match.  Not a big deal.  I have pictures of the drums somewhere, on a computer somewhere.....

[winr1]

All the truck axles I have had could not be redrilled

The large hole for a socket to remove the retainer nuts prevented redrilling

Have you found a place and price to respline the axles if you cut them short enough where you lose all the splines ??




Ricky.

[BattlestarGalactic]

Ugh, maybe, through faded memory, I didn't have the stock axles redrilled.  I forgot about that hole!!  Though that hole sure does make putting the retaining nuts on really easy compared to not having the hole. 

Apparently I didn't put the alum slots on til after I got the Moser axles?  I know I had them drilled for the 5 1/2" pattern.  They already come drilled for 4 1/2" and 4 3/4", they were able to put the extra pattern in for me.

[TomP]

I have seen 5 1/2" pattern axles redrilled. They need to drill the new holes close to the existing studs to avoid the access holes.
 But the other issue is the huge center stub on those axles not only means you can't get car drums to fit but you also are very limited in 4 1/2" pattern wheels with a large enough center hole.

Aftermarket axles would be the better way. Besides resplined axles are not too strong.

[gdaddy01]

www.rottenleonard.com​     look at this web sight , it is off of HAMB forum , may help you out .

[BattlestarGalactic]

Well, since the rearend has started howling in the truck, I pulled it apart last night.   The axles have the std 4 1/2" and 4 3/4" patterns drilled in them, then the extra 5 1/2" pattern too.  So I put the alum slots on after I got the axles, not before.

Don't know what happened, but last fall, this spring it started howling.  It's 25+ yrs old, never an issue.  Suddenly this.  Pulled it and the ring gear has a burr starting on the edge so I know it's junk.  It was full of lube, so it wasn't dry.  Pretty sure I used Redline synthetic in it.

[FElony]

Well, since the rearend has started howling in the truck, I pulled it apart last night.   The axles have the std 4 1/2" and 4 3/4" patterns drilled in them, then the extra 5 1/2" pattern too.  So I put the alum slots on after I got the axles, not before.

Don't know what happened, but last fall, this spring it started howling.  It's 25+ yrs old, never an issue.  Suddenly this.  Pulled it and the ring gear has a burr starting on the edge so I know it's junk.  It was full of lube, so it wasn't dry.  Pretty sure I used Redline synthetic in it.

You had the same fluid for 25 years?

[BattlestarGalactic]

Ya?  It was fine.  I only changed it a few years back when I put a new housing under the truck because the original one was bent all to hell from welding ladder bars on it back in 1992?  Done by local shop and while rearend was in the truck.   I put up with tires that wore badly to one side for a long time.  It finally beat the spring eye bushings out and I had another housing to use so I pulled it apart and swapped housings and replaced the spring bushings.  I put new fluid in and suddenly 4~ yrs later it trashed the gears.  It's not like the truck saw 20K miles a year.  More like 500 miles/year IF that.

Back in early 90's I went through a handful of gearsets.  I'd get a couple weeks out of them before they would start howling.  Richmond would not say anything was wrong with them.  Had a few friends go through the same issue back then.  I'll have to look at them, but I think I put US gear in it instead and haven't had a problem since.  Til now.

[FElony]

It seems that recommended change interval for heavy towing and/or hot climates is 30k for synthetic. No-tow in moderate/cool climates goes up to 150,000. The first scenario recommends 75W-140. Second, 75W-90. I wonder if old diffs are better off with non-synth. I also wonder if something is out of spec that would cause you to eat gears. Bent, machined, speck of crud where it shouldn't be? I also wondering if condensation buildup from limited use does something to that gear oil the way it does with engine oil. I'm doing a lot of wondering.

[BattlestarGalactic]

This is 35 spline spool, so no clutches to worry about.  I was amazed how clean it was when I pulled it apart a few years back.  Not so much as a mark on the gears and I heard all kinds of stories about running spools on the street.  Lash was still tight.  Now, it has a bunch of lash, big burr starting on the edge of ring gear.  It has to be just wear, so lack of lubrication qualities. 

It's been so long, I forget what Richmond was saying I needed to use for lubrication, but whatever I used on the US gears was fine, til now.  It was definitely synthetic because it was very thin, unlike gear lube.  I run redline synthetic in the wagon and got nearly 20 yrs out of the large pinion pro gears I run.  Finally chipped a tooth and I had to replace them.  Hope to get another 20 yrs out of it.

[BattlestarGalactic]

Well, I see it has Richmond gears in it.  Hmmm.   I guess this last set must of been better then the first few sets that wore out in a short time.  I know the wagon has US gear in it, but they are large pinion pro gears.

I wonder if the change in fluid is what caused the problem?   I forget what I used way back and pretty sure I just used Red line synthetic in it this last time.   I'm using US gears this time and will follow their recommendations for lube.

[Falcon67]

For the OP: my take - after doing this for years - is that you'll be money and time ahead to call someone like Currie and just order a housing.  Modifying one costs nearly as much in time and labor unless you have the welder, alignment tools, etc.  Last housing I bought made to order with ends and spring pads was a little less than $400 delivered.  I gave up hunting old housings years ago.  I learned some of that from Paul Peyton after I took him a nice clean Torino 9" housing to narrow.  He pointed out all the issues with the stock tubes, so in the end the only part usable was the center metal.  Several places produce new sheet metal centers and just about everyone uses thick wall 3" tubes.  Most of the aftermarket mounts are also designed for 3" tubes.  So you really need nothing from an old junkyard housing.

Lube - what gears were used in the truck - Street gears or Race?  The race gears are soft and wear quickly, especially in a street/strip application.  I have never had any issues running either conventional or synthetic rear lube.  I use conventional in the race cars because should something happen it's easier to clean off the track.  Synthetic just about has to be flamed off the surface.  Same reason I run conventional oil in the race motors.  I also now run a diaper, at least in the dragster.