I had both go bad in my Sidekick. If the Trans X does not work, then you should look at the valve. The valve might be good, but the hose might be leaking. My trans is really dirty and though I changed the filter and oil, the trans X cleaned the whole system so I have to yet put in another filter. My Sidekick was tampered by its previous owner in order to suck money out of his wife who owned the Jip and I've had to fix just about everything. Just to mention one mischief, the husband opened up the crankcase and loosened up all the berrings to the point that one of the half moon spacers came lose and made a noise like the engine had a bad berring. I just put in new berrings and torqued the whole thing and its been a year of good running.