47re vs 48rs and More

by Randy Stuppard on March 22, 2010

47re vs 48re and More

What is the difference between the 47re and the 48re and should we care?

A stock engine with a stock transmission works well under normal loads. But I hate to rely on the stock transmission when I have a loaded camper, pulling a trailer, gear and people. And when I add a programmer – the transmission has to be beefed up.

The first question:

What did your truck come with? (This is for the 3rg Gen trucks)

2003 S.O. Fed   Emissions: 250HP/460lb.ft. Available with NV4500 or 47RE
2003 S.O. Calif Emissions: 235HP/460lb.ft. Available with NV4500 or 47RE
2003 H.O. Fed   Emissions: 305HP/555lb.ft. Only available with NV5600
2003.5 The 47RE was replaced by the 48RE automatic transmission and available with the H.O.
2004 S.O. Calif Emissions: 235HP/460lb.ft. Available with NV4500 or 48RE
2004 H.O. Fed   Emissions: 305HP/555lb.ft. Available with either NV5600 or 48RE
2004.5 (50 state legal) 325HP/600lb.ft. Available with either the 48RE or NV5600
2005   (50 state legal) 325HP/610lb.ft. Available with either the 48RE or NV5600
2005.5 The NV5600 replaced with the G56 6spd manual gearbox.
2007 6.7L Cab and Chassis 305HP/610lb.ft with either the Aisin 6spd Automatic or the G56 6spd manual gearbox
2007.5 (50 state legal) 6.7L 350HP/650lb.ft with new 68RFE automatic and 305HP/610lb.ft with G56

For the ’03, a quick way to check which transmission you have is to see if the shifter says “o/d on/off” then its a 47re. If it says tow/haul its a 48re.

What are the differences?

One of the biggest differences is in the front clutch drum. The number of friction plates vs. steels and the planetary gears are slightly different.

The 48 RE has a stronger carrier. The 48 RE is just a little “tougher” in some critical areas for use with the Cummins HO engines.

The cases will interchange. The oddball is the 05-07 48RE with the TV motor instead of a TV cable.

The 47RE shifts under autonomous hydraulic control. The 48has electric TCC, electric governor, electric overdrive.

Can you use the parts from a 48re?

Yes. All of the 48RE parts fits in the 47RE case. You can use the 48RE VB, just change the “rooster cone” from the 47 VB to the 48 VB. Make sure you use ALL of the 48 parts. Dont mix/match them or you’ll run into clearance problems. Use the 48 pump as well, but be sure the convertor you use is for the 48RE. The difference between the 47 convertor and the 48 is the hub. The hub is different because of the sealing ring thats on the 48 stator.

You may think about upgrading to the 68rfe (6 speed) but they can’t be built to handle over 500hp (yet), doesn’t have the ecm for retrofit, and is very costly. You’d probably be better to go with a built 48 and a gear vendors OD unit. If you 3:73s, you may want to change to 4:10s if you go this route.

What can you do?

If you can find a 48RE to buy at a reasonable cost that would be good. If not, buy the parts to upgrade it and you’ll be good to go.

If you have a 47re, this is one idea. Order a rebuild kit for the 47RE (new clutches, steels, seals, gaskets), a transgo shift kit (or complete VB), new upgraded converter, and a billet input shaft. If you plan to run an exhaust brake, add the BD pressurelock.

When you’re done, add a lockup switch for mountain use. It makes the transmission act like a manual when you are on and off the throttle a lot. No lock-unlock at every on-off throttle and it runs cooler. Just make sure you turn it off when you’re out of the mountains.

And the final bits of advice.

Get a deeper pan as this keeps your transmission cooler.
Get guages. Trans Temp, EGT, the one of your choosing. Most go with Boost.

Now you can make sure your transmission never over heats, nor your turbo.

You’ll be amazed at how much better your truck performs with the new improved transmission over the stock factory one. Better mileage (if you keep your foot out of it) and a better chance of not getting stranded due to a weak link in your drivetrain.

Later
Randy

Resources:

Goerend http://www.goerend.com/  (St. Lucas Iowa)
Suncoast http://www.suncoastconverters.com/  (Fort Walton Beach, FL)
ATS http://www.atsdiesel.com/  (Arvada CO, but dealers in almost every state)
HTS http://www.htstransmissions.com (Lowell, MI with dealers)
PATC http://www.transmissioncenter.net/ (Bossier City, Louisiana
DTT http://www.dieseltrans.com/

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