Drivetrain rebuild
 

Ok so for I can't find anyone here who can give advice on a drivetrain rebuild. Right now my TII transmission in my '89 GXL is crappin out. Bearings wearing down. Syncros getting worse. you know how it is. In a few months the tranny is getting surgery and I want to know what to do while its apart, what parts to replace, and how to get the best performance out of it. Any advice on rebuilding a TII transmission and installing a 4.30 ring and pinion on a TII rear end?

Cryo treatment
 

Try having the entire tranny- minus the housing- cryogenically treated. It will make the gears tough as hell. Racers do it all the time. Cost will be around $200. Cheap insurance IF everything is in tip-top shape before the treatment.
Use Redline MT90 or Mobile synthetic gear oil for 1,000 miles then go to Royal Purple or Neo synthetic gear oil after the break-in.
Good luck W/ the rebuild. Remember, in car parts you (usually) get what you pay for.

More on cryo-treatment
 

Cryogenic treatment is the process of lowering the metal's temperature to MINUS 300 C, or so and then slowly letting it warm up. This realigns the molecules and greatly improves wear characteristics. I have done it with my .300 Win. mag target rifle barrel and it even cleans easier after shooting. It extends barrel life by 30%. That's with intensly hot gasses from the burning gunpowder trying to erode the barrel - a 30% increase is great. Finding a "perfect barrel is not easy and when you do you want to keep it.
I fully intend to do cryo when I rebuild/replace my current 3rd gen. manual tranny.
Youy could also (in addition) have it clamped on a special vibration table (I forget the brand name of this process) and have the gears & synchronizers vibrated at their special frequency for a similar effect.

Go find one in the junkyard or ask around in the second gen for sale section. How many miles is on the tranny?