So I found another th359 with the 203 transfer case going to put it in I got the old one out and the torque converter only had 2 bolts holding it to the flywheel one was about to fall off it was so loose the other was right there was no signs of the other 2 ever being in there at all any tips on things I should do to the one I’m putting in before installing it is there a gasket between the tranny and transfer case or just gasket maker? Should I change the oil in transfer case and tranny and the filter while it’s out what fluid do I use and woukd it be easier to do tranny then transfer case
Check front end play by pushing and pulling on the input shaft...You should have a little bit of longitudinal movement - if not, do not install that trans as it's bound up internally due to incorrect selective pump thrust washer (older units) or excessive shimming on the pump thrust bearing (later units).
Remove the pan and check for anything unusual (metal, lots of burnt clutch material, etc)...Assuming nothing odd is found, remove the filter (throw it out) and valve body. Install the Sonnax LBTH350 boost valve and spring kit...Inspect the spacer plate for any unusual signs of wear to the check ball locations...If none found, look at the feed holes for 1-2 and 2-3 - if they are opened up, you will know trans has been set up for firmer shifts...After that simply clean it off and set aside...Remove the spacer plate to case gasket and confirm you have all four check balls...If you have only one (and it's in the location of the modulator valve) then the trans has been further modified for firmer shifts. The check balls are all 1/4" steel and can be found anywhere transmission parts are sold. Pull off the vacuum modulator and throw it out - buy a new one. Meanwhile, pull out the modulator valve and inspect it for wear...These usually aren't bad but every now and again, ill see one with loads of scoring or excessive wear on one of the spools on the valve...If yours is as such, replace with a good used one but it's not likely so just check it to be sure.
With the VB off you can install a shift kit if one hasn't been installed already but that is up to you as you really don't need them in TH350s...You can set up to have the trans shift firmer or not based on feed orifice re-sizing in the separator plate, blocking the 2-3 accumulator (and even the 1-2 accumulator) if you are running a real high stall converter.
Push on the 1-2 accumulator cover on the side of the case to make sure you feel the repulsive force of the return spring pushing back against you. If you don't feel anything, remove the cover by taking out the snap ring (use a pick to pop it out via the small access port on the top of the servo bore on the case) and using large channel locks to pull the cover out of the bore. Replace the 1-2 accumulator spring and the sealing rings on the accumulator piston while you're at it. It's fairly common to see these springs broken and if it goes back in like that, you'll have super hard/back breaking 1-2 upshifts if running a factory stall converter, which could destroy the intermediate roller assembly if driven like that for too long.
Reinstall everything in observance of correct torque specifications and install a screen-style filter NOT a cloth style filter (cloth style filters can clog causing delayed engagements, clutch failure or neutral condition in all gears if it's totally clogged).
There is usually a gasket between the transmission and transfer case but RTV ultra black should work by itself if you cannot find a gasket.
