Ok, so I was just about to do a tranny flush (even tho alot of people say not to on a 200k vehicle), but my transmission started jacking with me and now I'm scared to. I have a 2004 GT with 200500 miles, BAMA Tune, and the 4r75W transmission BTW. It will not shift into 3rd unless under heavy load [3000-3500 RPM] (I realized how bad this problem is when I spun the tires on a damp road upshifting!
!) Occasionally the tranny will slip if the load is really high [above 4000RPM]. On stock tune, it will shift into 3rd from 2nd, and then briefly shift into 4th, on the tune it will go straight to 4th from 2nd when I almost completely let off the throttle (I think the tune does that because I am going over 40mph at that point). I can get it to not skip 3rd if I turn off O/D and it downshifts from 4th to 3rd just fine. I'm worried that I may need a rebuild, so what are y'alls thoughts on this plan, and putting a manual in it is not an option
Step 1: Drop the pan, check for significant metal debris, if minimal, pull the solenoids and test them with an DMM (should read between 20-30 ohms, correct?). If any are faulty, replace them, replace the filter, refill the pan, bolt it up, and drive on.
Step 2: If not, buy a rebuilt tranny and a stall torque converter. Unless, this problem could be caused by a dirty filter and I should replace the filter first to see if that fixes it before going the rebuilt route.
If I need to get a rebuilt tranny, what type/brand of converter would y'all recommend? 2k, 3k, 3.5k stall converter? This is a daily driver, and I have no idea of how a stall converter will effect its drivability. I can get a rebuilt transmission for $475 allegedly on craigslist with a 3 year warranty.