Got the bronco on the road, and everything was fine, for about a week. then i began hearing an odd sound. Sounded like an idler pulley on the verge of exploding, but i only heard it when the engine was under load (holding 3/4th, uphill). Once i would crest the hill, the sound would go away, and would then be replaced bya low vibration on the descent. No sounds or vibes while cruising along on a flat road, and nothing in 1st or 2nd.
Well, as fate would have it, the rear main sprung a leak, so i had no choice but to drop the trans, so i decided to take a peek inside, and see what i found. Sure enough, i found my culprit. In Pic 008, if you look closely, you will see the O/D apply piston snap ring has come loose from its groove. This is actually a known issue with the E4OD, and is a main contributor to the ultimate failure of the trans. Fortunately, many aftermarket companies have some up for a solution for this. In my case, i decided to use the updated snap ring made by Sonnax. While beig significantly harder to install than the OEM snap ring, tis guaranteed to never fall out.
Since i had the trans apart, i opted to install Sonnax's Pump Correction Package. In addition to an updaed front pump bushing, it also replaces the plastic drainback valve with an AL one, and it specs all sort of ports to be be ported, plus a few extra holes to be drilled, all of which help with shift engagement, converter lockup, and better oiling for the rest of the trans. Definitely recommended if you want your trans to last, and its pretty easy to do once you know where to drill.
On top of that ive replaced my leaky solenoid pack, and added a valve body from Punisher Valve Bodies.
The combination of the pump package plus valve body has completely changed the way the trans shifts (for the better), and guaranteed better oiling for a longer lifespan. And the updated snap ring has guaranteed that this trans will last many more miles.
There is a more detailed writeup of these mods done to the trans located on FSB, you can read the post here.