My '76 has this grinding problem with 1st gear. It goes through all the gears just fine but when I am slowing to enter a driveway or for any reason 1st grinds. If I come to a complete stop it will go in just fine. Is there a fix for this?

I've got the same going into second, and would have it for first if it hadn't been repaired 10 years ago. Its yer synchro and it needs replacing and it doesn't look too hard from pelicans tech article but-
You can monkey with the clutch cable and shift rod alignment to the shifter and maybe make it better for a while (pretty long unless you go for high miles....)
I'm prolly gonna replace mine this winter but it wold be nice to know if it really is just misalignment before i launch into that. I've been "adjusting" to the cars advantage and disadvantage, but right now seem to have a viable combo of no slipping and a little ca-chunk when I downshift to second if I don't double clutch. Which is another way to avoid the synchro thing entirely, but I remember when it was difficult for me to get first gear and it really sucked.

On some cars blipping the throttle just right will make it go in to first. On my car if I do it while still moving it will slowing fall in to first. I just keep pressure on it and it doesn't grind. Another trick is using the third gear syncro to syncronize the tranny. Basically you shift to third and then into first.

It shoudn't grind.
Your clutch cable either needs adjusting or you have a bad 1st gear synchro.
If it doesn't grind going into reverse than its definetly your synchro.

Fix the syncro now = $60, later = $400 + $60. The longer it does that the worse your slider will be and that is not cheap. If it has been doing this all along try adjusting your shifter after adjusting your clutch.
HTH

Improperly adjusted clutch and dragging pilot bearings are the early death of these trannies. That and not keeping them filled with oil.

1st gear synchro is a snap to change. It can be done with the tranny still in the car. Wayne's article is pretty good except I recently came up with a way to get the tail cover back on easier. Use grease to hold the reverse gear parts together and use grease to keep the reverse gear spacer in place on the intermediate plate.

I want to add two more things. Just as Dr. Evil said, replace synchro now is $60. Replace later is well over $500 in parts. The 1st gear slider is very very expensive.

And...Dr. Evil has one, repeat one, beautifully rebuilt 901 left...

Have you guys taken apart any 915s? I asked the same question on the Pelican Board about my SC tranny. First gear synchroes are worn but I can drive it without making it grind. Usually that involves coming to a complete stop before shifint into first. I only got one answer that said to wait and then just do everything. Should I consider just doing first gear synchros?

Anthony,
its the same as a 901 basically. I would recommend that you change the synchro now. The other gears synchros will wear out much slower and if you "wait to do the whole thing" you will need to pay considerably more as first gear takes a beating.
-Mike

Oh ya, you can just flip the synchro as well if it hasnt been done before. They have two sides. I t would likely cost you only for the seal kit.

As soon as I'm set up here in Houston, I'm taking apart the 915 and doing a tranny job. I'll write a companion article on the 915.

Then all I need to do is get my hands on a swing axel, and I'll be ready to write my book.

James