HELP transmission will not shift into first
 

78 sc No grinding and the clutch engages. All other gears shift fine, but first is blocked and will not go into gear. This has ocassionally ocurred where first is hard to engage, but now I am having no success no matter how much I try to finesse it into first.
Any suggestions before I take it to the mechanic would be appreciated.

Could be the synchro. Unfortunatly, this means the trans has to come apart to check.
All other gears engage ok? Have you tried the shifter adjustment procedure?

check your tranny bolts. i had the exzact problem your are having only to find out the the front two bolts were missing.... Wayne helped with the fix on that one. it may not be that but its worth taking a look

Check out the shift coupler. It is under that grate in the back seat. Remove the grate and make sure the bushings are ok on the coupler. There should be no play or missing bushings. You can order a bushing set from our host.

Here is a picture to explain what has happened.
http://forums.pelicanparts.com/uploa...1172090583.jpg
You see that the slider cant go all the way to right.
Because to many theet on the syncro hub is off.
So the syncro ring expand and stop the slider to slide all the way.

OUCH Today I drained the fluid and found one tooth at the plug and a few more when I took off the cover. Now I am wondering if I should pull the motor and tranny myself then give the tranny to my mechanic to rebuild. I have the 101 projects and the Bentley Manual. My experience has been changing out maintenance parts on my newer cars. If I take the tranny out myself I will save about $650.00 including $150 for towing the car.
Asking for opinions on if I should just bite the bullet to avoid frustration

Take it out yourself.
It will be great learning experience for you. You can see how different components work together and really how simple these cars can be.

Have a buddy help with the removal if at all possible. Doing it the first time by yourself, while not impossible, is safer with two people.

I agree, do it yourself. The first and second gear rebuild is actually relatively simple if that is all that is required. It is very rewarding to accomplish and there is a huge array of help on this board. Take lots of pictures, ask lots of questions, and just remember to get your detentes in correctly.