Been searching for answers on my 2 to 3 gear problem. This seems to fit the bill. #06-91 RE4F04A-RL4F03A A common complaint on above units is no upshift to 3rd gear hot or won't shift back into 3rd after kick down. The 2-3 shift may be OK with light throttle (low speeds), even hot, but may not have a 2-3 shift at high speeds. The cause of this complaint is usually undersize, flat or worn high drum inner seal or worn journal it seals on. Complaint ususlly occurs at 60-80 thousand original miles or shortly after overhaul when same type of seal is installed. TransGo SK kits have patented or patent pending Teflon inner seal with tension wire that fixes the leak "Forever." This is from TransGo 2006 bulletin Don't know if this helps or not, but information is always good to have.
