48re Transmission Guide & Information

48re Transmission - Transmission Cooler Guide

Based on the A618, the 48re is an electronically governed, ECU controlled four-speed automatic overdrive transmission that is a stronger version of its predecessor, the 47re.  The 48re has a torque rating of about 550-570 ft lbs, and Chrysler gives it a strength rating of 8.  Rather than being controlled by a TV cable, the 48re utilizes a solenoid-controlled valve body.

The transmission utilizes a Tow / Haul mode that can be found on the shifter. This changes the shift points and allows the torque converter to lock up earlier due to the elimination of 4th (Overdrive) gear.  This is used when towing or hauling as it’s name indicates to reduce stress placed on the transmission as towing in 4th gear isn’t recommended. 

48re Transmission Information

What Vehicles Were The 48re Found In?

3rd Gen Cummins Ram - Transmission Cooler GuideDue to its design, the 48re transmission is found heavy duty 3rd generation 2500 and 3500 Dodge Ram trucks from model years 2003-2007. While the 48re was capable of holding about 570 ft lbs of input torque, the transmission quickly became outdated due to the increased power capabilities of the 07+ Cummins that produced over 600 ft lbs of torque from the factory.

48re Transmission Specs 

Case Material: Aluminum 

Torque Rating: 550-570 ft lbs

Weight: ~250 pounds (Dry)

Gear Ratios:

  • 1st Gear: 2.45:1
  • 2nd Gear: 1.45:1
  • 3rd Gear: 1.00:1
  • 4th Gear: 0.69:1
  • Reverse: 2.21:1

48re Transmission Fluid Type & Specs

ATF+4 Transmission Fluid - Transmission Cooler GuideThe 48re takes ATF+4 transmission fluid and has a 14.5 – 16.5 quart dry fill capacity.  When dropping the transmission pan to perform a standard drain and fill transmission fluid change, you can expect to replace around anywhere from 5-7 quarts of fluid assuming the stock transmission pan is being used.

If you have a deeper aftermarket transmission pan on your 48re, then this quart estimate will likely be more and require you to ensure you have enough fluid to perform the service.

Get The Best Price On ATF+4 Transmission Fluid

48re Transmission Fluid Temperature

Like all transmissions, it’s best if you run your 48re in the 160-180 degree range for best performance and longevity.  The 48re is designed to run in the 180-200 range, which is still in a safe range, but can easily go over 200 when towing or hauling due to the added load.  The transmission temperature chart shows how long you can expect a transmission to last at a given temp.

Transmission Fluid Temperature Chart

When the trans temps start getting too warm and into the 250-260 degree range, the truck’s PCM will command the torque converter clutch to lock up in 3rd gear to reduce the stress of being in overdrive with a heavy load.  The PCM will keep the truck out of 4th gear until temps get below 230 again. 

On the other end of the spectrum, when transmission temps are too cold, the PCM will keep the toque converter from locking up when under 50 degrees. 

To combat transmission temp issues, installing an aftermarket transmission cooler is certainly helpful along with a deeper, higher capacity transmission pan.  

As always, it’s a great idea to monitor your transmission temps with a transmission temperature gauge. Find the right transmission temp gauge to monitor your 48re with out Best Transmission Temperature Gages write up. 

48re Transmission Filter

Transmission filters for the 48re are very inexpensive and simple.  Most  48re transmission filters and kits (including pan gasket and filter seal) cost around $20 – $30.  The filters we recommend for your 48re are:

48re Transmission Maintenance

Due to its simplistic design, the 48re requires basic maintenance that is fairly easy to do.  It’s typically recommended to change the fluid, filter, and adjust the bands every 30,000 depending on usage.  If you tow or haul often, it’s best to check your fluid and make a determination as to how frequent you should change out your fluid.

When checking your transmission fluid, be sure to not only look at the fluid level, but the color and smell. Good transmission fluid will have a reddish color to it, but if it looks dark, almost brown and has a slight burnt smell to it, then you are very past due on your maintenance.  The chart below shows how transmission fluid looks at various stages.

Transmission Fluid Color Comparison - Transmission Cooler Guide

48re Transmission Fluid Change

Changing transmission fluid in your 48re is a very simple job for the average DIY weekend mechanic.  In all actually, the hardest part of the job is draining the fluid from the pan if your pan doesn’t have a drain plug. This is quite common with more transmission fluid changes.

Below is a detailed video of performing a transmission fluid change on a 47re, which is the same procedure as the 48re.

How many quarts does it take to do a fluid and filter change on a 48re trans?  For a typical pan drop and fluid change, you will need about 5 quarts to do the job. 

As always, start with adding a few quarts of atf when you have the new filter and pan back on and shift through the gears to get fluid moving and warm, then keep checking and added until you have the right level.

48re Band Adjustment

The 48re has 2 bands, the front and rear. The front band is much easier to access compared to the rear due to the rear band being inside the transmission case.

What are common 48re band adjustment symptoms? If bands are not adjusted at their recommended interval of about 30,000 miles, there might not be any immediate symptoms.  However, if bands aren’t adjusted overtime, they will begin to slip which may in turn cause the transmission to slip as well.

With the 30,000 adjustment interval, adjusting the bands in a 48re should be done at the same time as a fluid change as part of regular maintenance.

This older post on Cummins Forum and the video below both do a great job of outlining what’s needed as far as tools, specs, and how to go about adjusting the front band on your 48re.

For those who would rather have a better visual aid to follow, this step by step list is a great resource as well.

48re Band Adjustment - Transmission Cooler Guide

48re Upgrades

When it comes to upgrading your 48re, besides adding better internals and hard parts, there are a few simple upgrades that you can make to keep transmission temps down.  The most common simple DIY 48re upgrades that can be done with simple hand tools in your driveway without removing the transmission to tear apart are definitely transmission coolers, pans, and servo.

If you’re more mechanically inclined are are ok with transmission removal, then there are number of internal upgrades you can do yourself, or have a shop do for you.

48re Transmission Pans

Derale 14210 Transmission Pan - Dodge A518 46RH 46RE / A618 47RH 47RE 48RE - Transmission Cooler GuideUpgrading the transmission pan on heavy duty trucks is a very common modification.   Most aftermarket pans are deeper than the factory pan which allows for greater transmission fluid capacity.  The biggest benefit of greater fluid capacity is that it helps in keeping transmission temps cooler which can help with transmission longevity and performance.

The beauty of the 48re is that you have a ton of aftermarket support when it comes to transmission pans.


Get The Best Prices On 48re Transmission Pans

Best 48re Transmission Coolers

Mishimoto MMTC-RAM-03SL transmission cooler - Transmission Cooler GuideCooling your 48re might be a challenge for some if you live in a warm climate or use your truck for a lot of heavy hauling or towing. If your truck deals with higher than average transmission temps, it’s recommended to add a transmission cooler to your truck.

We did an in depth write up about the Best Cummins Transmission Coolers, and for your 3rd gen Cummins, the Mishimoto MMTC RAM-03SL is hands down the best 48re transmission cooler upgrade due to its direct fit and serious cooling capabilities.

If you are looking for a lower cost alternative, look no further than the Tru Cool 40k. The Tru Cool 40k is our recommended transmission cooler for most heavy duty applications, so fits the bill when it comes to keeping your 48re cool.

Transmission Cooler Direct Fit Price
Tru Cool 40k transmission cooler LPD47391Tru Cool Max LPD47391 No Shop Now
Mishimoto MMTC-RAM-03SL transmission cooler - Transmission Cooler GuideMishimoto MMTC-RAM-03SL Yes Shop Now

Mishimoto MMTC-RAM-03SL Specs

3rd Gen Ram Cummins 48re Mishimoto MMTC-RAM-03SL - Transmission Cooler Guide

Like many Mishimoto transmission coolers, the MMTC-RAM-03SL is specifically designed for the 03-09 5.9L and 6.7L Cummins. this cooler is a direct fit application that requires little effort installing.  The cooler features a 244% increase in fluid capacity over the factory setup and a 212% increase in total core volume. 

Cooler Dimensions: 26″ x 10.94″ x 0.87″

Cooling Rows:  48

Fluid Capacity Increase:  0.88 quarts

Fitting Type:  3/4″-16 SAE Barb

Installation Kit:  transmission hose, fittings, worm clamps, thermostat bypass

Get The Best Price on Mishimoto MMTC-RAM-03SL Transmission Coolers

Tru Cool 40k Specs

Tru Cool 40k Transmission Cooler With Installation Kit - Transmission Cooler Guide

As we’ve discussed a number of times, the Tru Cool 40k is head and shoulders above other universal transmission coolers in the heavy duty use department.  Sure there are other transmission coolers that might be larger or include a fan, but for the cost consistent performance, and simplicity, it’s hard to go against the Tru Cool 40k for the money.

Cooler Dimensions: 8 1/2″ x 22″ x 1 1/4″

GVW: 40,000 pounds

BTU Rating: 45,000

Fitting Size: 3/8″ inverted flare hex with 5/8″ thread size –  This is great for those looking to install custom transmission lines

Installation Kit:  Yes – Includes universal installation kit with rubber transmission line, various fittings, clamps, and mounting hardware

Get The Best Price on Tru Cool 40k Transmission Cooler

Installing a transmission cooler such as the Mishimoto MMTC-RAM-03SL or Tru Cool 40k will drastically lower transmission temperatures and help with the longevity of your transmission and fluid. 

48re Common Problems

48re Diagnostic Trouble Codes (DTC)

48re Transmission DTC Codes - Transmission Cooler Guide

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48RE Transmission Guide & Information
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48RE Transmission Guide & Information
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Get information on everything related to the Mopar 48re transmission.
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Transmission Cooler Guide
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