Ironhead trans door fitment

[Gold Member]

I think I know the answer to this question but I'm paranoid about the fitment and need to hear it one more time.

I've got a trans door that is not original to my case. A couple of the hold down bolt holes don't line up.

On XLF the guys here say the doors are standard; they are machined to be interchangeable as the shaft alignment relies on the alignment of the dowel pins and the dowels are aligned with the shafts and bearing holes in both the door and the case. IOW the dowels and shafts always line up, and if the hold down bolt holes don't line up, this is irrelevant; all you have to do is adjust the hold down holes with a file, and you are good.

Right? Because I'm soon to put my trans in.

[ericfreeman]

Biggest concern is how the mainshaft will align with it's bearing on the sprocket side. I bought a Vulcan aftermarket trapdoor and while the fit on the dowels was good, the mainshaft was shifted in the bearing. I could only fit the bearing rollers by pushing the mainshaft to one side which I figured wasn't a good thing for longevity. Used the original trapdoor instead.

Only way you'll know for sure is to modify the trapdoor until it fits the bolt holes and dowels and then check mainshaft clearance in the bearing race.

[Gold Member]

Originally Posted by ericfreeman

Biggest concern is how the mainshaft will align with it's bearing on the sprocket side. I bought a Vulcan aftermarket trapdoor and while the fit on the dowels was good, the mainshaft was shifted in the bearing. I could only fit the bearing rollers by pushing the mainshaft to one side which I figured wasn't a good thing for longevity. Used the original trapdoor instead.

Only way you'll know for sure is to modify the trapdoor until it fits the bolt holes and dowels and then check mainshaft clearance in the bearing race.

I forgot to mention the race is brand-new and not lapped yet, the m/s is brand new, and I gave him 100 USA made new rollers, standard size. He is to pick me out 23 rollers that are all identical, in case there are any over- or under-size in the lot. Anal retentive of me I know, but I'm getting close to assembly and don't want any more delays if I can help it.

I hope I'm on the right track?

[ferretface]

Originally Posted by Gold Member

IOW the dowels and shafts always line up...

Not so. I have a 'spare' trans with the same trapdoor casting numbers; it would not go in with just the two dowels + m/s & c/s in place. I didn't try to force it. My OEM trapdoor was fine so I reused it with all-Andrews gears & shafts.

You pays you money and you takes you chances..

[Ferrous Head]

The location of the bolt holes that hold the door on are not indexed to anything.

They will almost never line up if you swap doors.
It doesn't matter.

They do not locate the door, the dowels do that. AT times the bolt holes will be 1/4 inch out. Last one I did I went through 5 doors (I have some spares) before I go one that was close. In the past I have just drilled the holes in the door out.

The doors are NEARLY interchangeable. Had HD indexed the bolt holes to something they would be.

But the important bits, holes for the shafts will align with no problems.

You will know when you have put a gearbox together right. It takes very little to cause a problem, binding and so on.

Once the box is installed you will be able to change through all the gears and the main shaft will spin quite easily.

Oh. There is a "special" lube for gearbox assembly. If you don't have some I would suggest you buy it. Actually called "Transmission Assembly Lube".