Article by scottericsonon of the XLForum ¹⁾

A used transmission bought from Ebay was disassembled and the parts swapped over to the original trapdoor.
The used transmission had all Andrews gears as well as the mainshaft and countershaft.
I put new main and countershaft bearings in my trapdoor so I could reuse it so I know everything will line up with my case.

Empty trapdoor.
I should note that while it was empty, I DID punch out the countershaft oiler plug so I can set endplay later.

Clutch gear with new bearing loaded into trap.

Mainshaft loaded in. You WILL have to pull it back apart again but I wanted to get the trans loaded just so I could see how everything fit together before I put the shift forks in.

(L) Countershaft in too. Spin it a couple times and slide all the gears around to see that everything operates free.
Then tear it back down and then start reassembly WITH the shifter forks.
(R) Slip your C/S fork around it's gear (3rd) and get the finger roller in the cam.

(L) Then get your mainshaft fork in position and slip it's gear (2nd) in from the side.
(R) Slip your mainshaft into it's home thru 2nd and clutch gears and put low back on the countershaft not forgetting your washers (74 and up have 2).
Then go ahead and slide your fork shaft in and run her thru the gears a handful of times.

Here is the transmission completely assembled to measure clearances on the gears.

After you get it all together, run it back and forth thru the gears a handfull of times.
This is to get everything settled into where it's supposed to be (plus it's neat to see how everything works together)
Put it in neutral to measure your clearances.
(R) Measure spacing between C/S low and C/S 3rd like this. You want .038“-.058” here.

(L) You adjust clearance with these washers.
(R) Then measure between the dogs on C/S 3rd the face of C/S 2nd like this.
You want .038“-.058” here as well.

(L) Then check between M/S 2nd and M/S clutch gear .043“-.083” of clearance.
(R) M/S 2nd and M/S 3rd .043“-.083” here as well.

Checking C/S clearance. I have .006“
Don't mind my redneck setup. I'm just a poor bastard trying to do shit on a budget.

Putting some pressure on the M/S to emulate the clutch being there and engaged.

(L) Checking the M/S endplay. I have .006”
(R) Grab your shift shaft and slide it into its home making sure to have it level so it will go into it's pocket on the trans.

Grab your M/S rollers making sure to COUNT THEM so you know you have all 23.
Goo up the race and your C/S bearing and put all 23 rollers into place.
MAKE SURE you put the flat washer in between the circlip and your bearing rollers!! Did you check that it was there? Good…now check again.

I greased up the rollers too so they would stick real well for me.

Cross your fingers and slide the trans in. If it's in right it should ALMOST seat by hand.
At least it should start on the dowels. If not, try wiggling it some. It will line up.
Get your bolts in tightening each of them a little at a time so that your trapdoor goes in straight.
Then when they're all tight, pull them one at a time and put a dab of Loctite on them.