48RE Transmission Rebuild And Install

48Re Rebuild And Install 48Re Transmission

If we don’t count the addition of electronic controls and gradual mechanical and fluid dynamic improvements—the basic design of the 48RE Chrysler transmission found in our ’06 Dodge Ram 2500 has been in production 52 years. This legacy is good for two reasons: First, it means the initial foundation was solid, and secondly, it gave plenty of time for performance shops to beef up the internals one destructed part at a time—until it became bulletproof. Besides stronger parts, transmission gurus such as Ernie Davis at Sun Coast Converters have invented and refined new control strategies so parts stay alive, even during extreme racing conditions. Follow along as we look at the origins, development, and installation of a Dodge 48RE transmission, which stands for: (4) four speeds, (8) level eight torque rating, (R) rear-wheel drive, and (E) electronically controlled transmission.

48Re Rebuild And Install Torque Converter Machining

The thing that makes Sun Coast different than most transmission shops is it doesn’t rely on outsourcing for its enhanced transmission parts, like this torque converter we witnessed in the making. Sun Coast was established in 1989 and started producing bulletproof torque converters at its facility in Florida, which has a room full of CNC machines. All this technological know-how was gained by listening to the problems of the customers and finding solutions.

The thing that makes Sun Coast different than most transmission shops is it doesn’t rely o

Simpson Planetary Gearset
In 1956, Chrysler licensed Howard Simpson’s transmission gearset technology and the legendary TorqueFlite instantly became the envy of the world. A few years later, GM, Ford, and a few others bought the Simpson design and adapted it to their transmissions. All stayed relatively unchanged at the basic level until the ’90s in cars and ’10s in trucks. The Simpson planetary gearset consists of two planetaries connected by a sun gear. The heart of an automatic transmission is the planetary gearset. Planetary gearsets allow a transmission to have several different gear ratios, with different clutches holding certain components stationary.

Planetary gearsets are made up of a sun gear, planet gears, the planet gears’ carrier, and the ring gear (also known as the annulus gear). Each of these three components can be the input, output, or can simply be held stationary. Two clutches and two bands are able to manipulate three forward gears, one neutral, and one reverse speed. In later four-speed transmissions, a third planetary is located in a housing bolted to the rear of the main case (it’s also controlled by a clutch).

The Simpson legacy lives on in the trucks we drive today and in the SAE/Timken-Howard Simpson Automotive Transmission and Driveline Innovation Award, which was established in 2007. If you want to learn more about Howard Simpson, check out “Man with a Pencil: Engineering Genius of the Modern Automatic Transmission,” Motor Trend, Vol. 16, No. 10, Oct. 1964, page 82-85.

Driving a Bulletproof Transmission
Dodge’s four-speed automatic transmissions require an aggressive shift pattern and increased line pressure to cope with the torque of a modified Cummins. The owner of the ’06 Dodge Ram in this article was at first alarmed by the firmness of the shifts from the Sun Coast 48RE we installed. This is a common experience, as worn-out transmissions have a tendency to feel smoother than they should as they are slipping their way into oblivion. In our experience, once the owner gets the feel for when the truck likes to shift, the new combination is very fun to drive.

Each Sun Coast torque converter is tuned to the needs of the particular engine it supports by means of precise measuring equipment that adjusts the distance between the internal components and fin pitch that affects the stall speeds. The original torque converter is cut in half and rebuilt with a billet stator, billet piston, increased clutches, and CNC billet-steel cover. Though the lockup torque converter was introduced in the late ’70s, it wasn’t until the dawn of diesel performance that it was seen as desirable.
Each Sun Coast torque converter is tuned to the needs of the particular engine it supports
After our core transmission arrived at Sun Coast, it was totally disassembled and cleaned in a separate room. So many things go into a Sun Coast transmission that it’s not accurate to say it’s just a rebuild kit. Although many parts, including the case, overdrive housing, intermediate shaft, and output shaft were inspected and retained. New parts for our particular build include a billet-steel input shaft, bands, struts, anchor, forward piston, direct piston, one and two servos, accumulator piston, valvebody, and governor solenoid. A TransGo shift kit, complete gasket kit, and Sun Coast torque converter complete the package. Also, new and sometimes more clutches replace the old ones. Better clutch material is definitely one advantage we have over the older transmissions.
After our core transmission arrived at Sun Coast, it was totally disassembled and cleaned
The case houses two servos that are basically pistons controlled by hydraulic pressure. When pressure is put to the passage, the piston rises and pushes the lever called a strut. The strut clamps the band and holds the outside of the drum—this combined with the clutches controls a gear change.
The case houses two servos that are basically pistons controlled by hydraulic pressure. Wh

On the left is the billet input shaft and direct hub. It’s important to get a stronger billet input shaft if you upgrade to a stronger triple-disc converter that’s able to lock at a lower rpm. To the right is the intermediate shaft with overdrive planetary system assembled (the stock output shaft is on the bottom). Inside the overdrive hub is a pressurized 180-pound spring. Although these parts aren’t as big as some of the ones found in newer transmissions, they have proven themselves in 1,000hp drag trucks—and they have less rotating mass to get moving.
On the left is the billet input shaft and direct hub. It’s important to get a stronger bil
Here the overdrive housing was bolted to the aluminum case where the two planetaries are housed. The first TorqueFlite, named the A-488, was released in 1956 and had a cast-iron case and a second hydraulic pump in the rear so it could be push started. It only had three speeds, since it didn’t have the overdrive housing. This remained majorly unchanged until 1989, when the first Cummins was mated to the three-speed 727 transmissions.
Here the overdrive housing was bolted to the aluminum case where the two planetaries are h
This is a valvebody test rig. The valvebody controls the personality of the transmissions, and it was completely reworked by Sun Coast to actuate the clutches and servos that control the gears. A pump mounted in the front of the transmission creates the hydraulic pressure that’s used in the transmission.
This is a valvebody test rig. The valvebody controls the personality of the transmissions,

A gasket was placed on the case before the final step of the Mag-Hytec deep pan installation. The valvebody was bolted on and the filter was installed.
A gasket was placed on the case before the final step of the Mag-Hytec deep pan installati
The fitting on the left is the transmission fluid coming out, so it is very hot. Moving to the right is the shift actuator. The square, electronic plunger is the neutral safety switch that only allows the transmission to start in Park or Neutral. The five-pin connector means it’s a 48RE instead of a 47RE, which usually has a three-pin connector, except in some of the later models. The final fitting on the right is where the cool fluid from the cooler or external bypass filter enters the transmission.
The fitting on the left is the transmission fluid coming out, so it is very hot. Moving to
We then had the transmission installed by the experts at Tim Moye Transmissions in Lutz, Florida. Grease was applied to the input shaft and the torque converter was placed. Grease was then applied to the center hub. Vinny Rodriguez showed us a trick when he marked the location of the threaded holes with a red line to speed installation later on.
We then had the transmission installed by the experts at Tim Moye Transmissions in Lutz, F

Having the proper tools, like the transmission stand, truck lift, and extra-long impact extension, saves time and effort. At this point, the driveshafts were marked so they would be put back the exact way for proper balance, a glove was placed on the transfer case to catch fluid, the lines were disconnected and capped, the transmission shift linkage and transfer case shift linkage were disconnected, the electronics were disconnected, and the crossmember was removed.
Having the proper tools, like the transmission stand, truck lift, and extra-long impact ex
With the transmission out of the way, we removed the original flywheel and installed this one from Sun Coast. The bolts got Loctite.
With the transmission out of the way, we removed the original flywheel and installed this
The transmission was raised back into place and the transfer case was bolted on— although you can raise the whole thing up as an assembly. It’s important that the bellhousing rest flush with the engine before installing the bolts. The new bolts that came with the torque converter must be used since they are a different size than the original ones. We installed them with Loctite through an access panel on the passenger side of the engine. A barring tool or a flat screwdriver on the flywheel turns the engine to access the bolt holes. We filled the transmission with 19 quarts of fluid and did a flawless testdrive.
The transmission was raised back into place and the transfer case was bolted on— although