The MAIN issue with the 48RE is they can't tolerate much in the way of debris (primarily band material) getting on the screen of the Solenoid. When it operates, it doesn't move the shuttle valve very much (maybe 1/64"), so it doesn't take much band material on the screen to bugger up it operating properly and your tranny will start to fail.
I've had luck with the GM Solenoid kit which are larger and more robust than our OEM units.
When the transmissions start to go rarely (if ever) does a band adjustment and/or fluid change help; as the band material keeps flaking off and causing the same problem. Once the band material is gone (which doesn't take long), you have metal on metal and things get more expensive to repair. At that point, it doesn't matter if band material is plugging up the Solenoid or not.
I went with an old "Hemi Rigid Band" and was steered clear of the "Red Eagle" clutches as they are designed to grab AT FULL THROTTLE.
Some kind of a shift-kit (or better yet) valve body mods by someone that knows what they are doing, will keep the line pressure high-enough so the band and clutches can survive full-throttle shifts.
I chose a torque convertor in the 26-2800 range which really makes a nice difference when street driving and launches hard at the track. Strongly recommend this mod!
Our trannys have their roots in the 1950s and
are quite marginal for the SRT-10 which is why the factory ecu programming killed power during a full-throttle shift which helps them live; Many manufacturers do that today to keep autos alive. Even my Smart car (which doesn't make enough power to hurt itself anyway).
The 48RE needs a little help to survive; and if you are adding more power, need to be built accordingly.
If your engine produces more power than stock (say 75 more), find someone that can build the tranny to withstand more power. NO point in rebuilding to stock specs.
Also, there is a check-valve (ball) inside the cooler hose (near the radiator, driver's side) that has been known to fall apart and plug things up. Have a hose made that doesn't use a check valve. It was in there to prevent drain-back and slow transmission engagement if the vehicle has sat for a while. It is an simple valve body modification that will allow you to run without that check-valve and will lubricate the transmission properly.
On the topic of valve bodies, these transmissions can survive without a shift that is so hard you will loosen fillings in your head. Living with those on the street is not fun and YOU WILL eventually break some parts.
If you can't find someone locally to fix it properly, box it up and ship it to someone that can. Try to get some references because I went through a few "We can Fix That, No Problem !!" guys before finding a guy that really could.
Good luck.
PS I'm sure you will get guys coming on here trying to convince you to go to a 6-speed.
