Did you calibrate the PCM for proper MPH and correct shift points after the tire size change?
If not, how far off is your speedo and OD right now?
If yes, than your going to have to do it again after you change the gears out.
For a 37" tire, 488:1 is the lowest I would go, and since a D35 can't go any bigger than 513:1, that's your max.
You can find out what size gears you have by finding the code on the door tag for axles. Also the rear differential should have a tag on one of the bolts, saying what it is. I like to match them both up, to make sure they are the same. If not, then the cover comes off, and finding out the old fashioned way.
What MBrooks is trying to tell you is there is no faster way to kill an expensive transmission repair, by changing to bigger tires, without doing the rest of it. Gears and PCM flash are part of it, and there is more you can do, but those are bare minimum.
If you already know all this, awesome, but for someone that doesn't, and happens upon this thread, they will after.
