I've seen this 100 times before, but my advice isn't always the answer: It sounds like you need to service your trans if it hasn't been done already. Don't go by the condition of the fluid at the end of your dipstick to verify the overall condition of the fluid. Drain a little out into a clean, light-colored container to see what your ATF looks like. It's very possible you need a drain & fill & also a filter replacement. By any circumstances- DO NOT take the vehicle anywhere for a trans flush, unless you want to rebuild the trans & get all the scum the flush loosened up & re-introduced into the system.
What happens is you've got so much build-up in your accumilator, valve body, & pump & it'll make deposits in certain key areas, valleys, & valves inside your trans. The heat from the friction loosens up this scum during warm-up & allows the fluid to flow more freely to where it needs to go. This is the most probable reason why it runs like poo when it's cold & runs better at operating temp. When you've got build-up that bad & if you can afford it, it wouldn't be a bad idea shopping for some performance upgrades, including a master rebuild kit, & get a full rebuild on the trans. If you do it yourself or it gets done somewhere, make sure after the tranny's torn down that the inside of the case get a good pressure wahsing. You can also clean out the accumilator with brake cleaner or mineral spirits. Get an upgrade valve body & TC, & life will be great.
One last thing- check the pull ring on your dipsticks. Read what it says to use on the top. It'll either say MERCON or MERCON V. Back in 2006, Ford has posted a bulletin that MERCON V works in all of their transmissions. This is NOT entirely true. If your dipstick says MERCON: USE MERCON!!! I had seen somewhere that someone had posted that they no longer manufacture MERCON. This is also not entirely true. Ford may have, but there's still plenty of MERCON on the shelves at your local parts store if you want to go the conventional route. Then of course, there's plenty of aftermarket companies(AmsOil, Lucas, Royal Purple, Red Line, etc.) that make excellent synthetic oils in the MERCON/DEXRON III variety, depending on how much green you want to spend.
Without having to pull out the trans, you can check the shift valves inside the accumulator.You'll need a 10mm socket, & a small set of internal snap ring pliers. Drain all the fluid out of the pan & then drop the filter(discard BOTH). Your accumulator is the rectangular box just behind the hole the filter mounts to. I think there's either 8 or 10, 10mm bolts that hold the accumilator in. Drop the accumulator & put it on a flat, clean surface. Use the snap ring pliers to remove either snap ring(DO 1 AT A TIME!!!! YOU DON'T WANT TO LOSE OR CONFUSE THE PIECES!!!). After you get the snap ring(s) out, remove the pieces 1 by 1 & lay them out on the clean surface you're working on EXACTLY as they came out in order. Check the condition of the springs & the stopper & make sure they're immaculate before going back in. After you clean the pieces, check the orifice(s) the pieces came out of & clean any dirt or scum inside them. It is safe to use either brake cleaner, parts cleaner, or mineral spirits to clean the pieces & the orifices. If you use parts cleaner, DO NOT SUBMERGE the accumulator into the parts washer. Put the pieces back in EXACTLY as they're laid out & also make sure the snap rings are completely locked into their grooves. There is no adjustment on the accumulator; just reinstall & use your better judgement on the tightness of the bolts. I do not have the exact torque spec on these bolts, but you can find them either in a Haynes maunual or online. I usually go by the "memory" of the threads by turning them snug & giving them a slight turn until they stop using little physical force. YOU DO NOT WANT TO CRANK THESE BOLTS DOWN OR YOU COULD BREAK EITHER THE BOLTS OR THE ACCUMULATOR ITSELF.
I know I type too much stuff, but working on the 4R100/E4OD isn't as bad as everyone thinks it is.There's just too many little steps to perform on some of the easiest jobs on these things.
Last edited by RadarRider; 01-21-2013 at 08:32 AM.