Mesh, splines! Mesh damn you mesh!

I'm installing my new ax5 into my '85 XJ and we've encountered a problem. Just put in the new clutch kit, went in fine. Jacked ax5 tranny + np207 transfer case up into place and we cant get the splines on the input shaft to mesh into the engine. Already checked to make sure that the spline count and everything is fine. The alignment tool which slides in perfectly is identical to the input shaft of the tranny, but we cant get the thing to mesh in. We've tried wiggling the output shaft with it in gear to mesh it in, but no dice. We've looked to see if something is in our way hanging it up, but nothing is in the way. The throwout bearing is installed properly on the clutch fork, so its not that. the clutch is installed correctly.

Anybody got any ideas on getting it in? We got pissed and gave up on it for today, but we're gonna try to finish it tomorrow. The only ideas we've got so far are to unbolt the transfer case to make the thing a lot less unwieldy in there. I think we could get it in that way, maybe, but bolting the transfer case in after the tranny's installed is going to be a major pain in the @$$.

Any ideas anybody?

The tranny input shaft doesn't "mesh" into anything on or in the engine. It meshes with the drive hub of the clutch disc. That's what you need to confirm the spline count on.

However, the snout of the input shaft also has to fit into the pilot bearing/bushing (don't know which it is on a 4-banger) in the end of the crankshaft. If you are installing a tranny from a different year XJ (or from a Wrangler), you should verify that the pilot bushing is the correct I.D. to match the tranny, and also inspect it visually to be sure it hasn't gotten bashed up enough to prevent the snout of the tranny input shaft from fitting.

The tranny came out of an identical 85, so i know that everything there should be fine. I'll see if i can check the condition of the pilot bearing tomorrow and see if we beat it up trying to get it in.

The alignment needs to be perfect between the engine and tranny. I have experienced the same scenario as you describe above with an engine and transmission that were previously (and presently) mated. On one occasion, they practically fell together. On another, it took an hour to get them to mate.

If the splines are right, just keep at it.

We took off the transfer case and tried again today, but it still will not go in. We're getting desperate now. Anybody know if the splines were changed a few thousands mid-year or if they're something that usually gets in the way that we might not have noticed?

can you unbolt the clutch from the flywheel? then make sure the clutch disk will mate with the shaft (off the vehicle). if everything fits that way, it should fit on the vehicle. When putting it back on, try to align the splines before you put it in. use the alignment tool to place one spline at 12 o'clock, and then rotate the input shaft to the same position. Then try to hoist everything up into place....

Well, thinking back to mistakes I have made in the past, I'll ask a couple of insultingly basic questions:

1. Your first post said you put in a new clutch. Did you verify that the splines on the new clutch actually fit over the input shaft of the tranny before you installed the clutch?

2. Did you use an alignment tool to be sure the clutch disc was precisely centered before tou tightned down the clutch pressure plate? Did the alignment tool have the correct adapter on the tip to center up properly in the pilot bearing/bushing?

Yeah, you guys are both right. We had tested with the alignment tool and found that it worked in both the old and new clutch, so we'd figured they were the same. We just now took off the clutch and tested the disc on the shaft of the tranny, and lo and behold, it doesn't quite fit. The size is basically the same, but its off by a few thousandths. We're in the middle of filing the disc's teeth very carefully now so that it will fit, and everything should work now. thanks for everybody's help.