Based mostly on the advice of a transmission expert we trust, we just purchased a 48RE that came out of 2004 Ram due to a 750HP upgrade project. In other words, it came out to make room for an ATS Stage X.

The plan is to take the core out of the 48RE, rebuild it and place it into our current 47RE case. Considering the low-speed shudder we've now developed, we're seriously considering a new torque converter and [possibly] a new valve body.

Other than a set of RV275s, the internals of our CTD are factory stock. And although we will be towing a 24' gooseneck from time to time, we will probably never add any high horsepower modifications to our 5.9 liter.

With all of this in mind, I was hoping to get some recommendations from the 3rd generation folks about "building up" a 48RE -- without breaking the bank. In other words, we want a beefier towing transmission, but we don't need a firebreathing sled pulling tranny by any means.

Which parts are suspect in a factory 48RE and, more importantly, what would you replace if you were rebuilding an early 2004 48RE?

Obviously, thoughts on an appropriate torque converter and valve body would be much appreciated as well. I'd also like to get thoughts on ensuring that the overdrive unit we end up with is much better than stock.

Thanks for your time...

 

Not sure the cases will interchange!!!!

 

All the electronics in the 48RE and the 47RE are the same. The 48RE runs higher pressures. If it is a 2wd I would be willing to bet you could put the 48RE in the truck and just have to change the front yoke on the driveshaft to make it work.

 

I do know some of the earlier year 48re's had a problem with breaking input shafts due to a bad batch of heat treatment. The stock 05's and later seems to be much better. Since you've got the goodies out I'd consider new bands, clutches and seals.. Goerends T/C and V/B when purchased come handy dandy instructions with a great product to boot!

 

B&W

The stock 48RE will handle stock power but that's all! The first to go is the TC lockup clutch. It will begin to slip at high torque low RPM conditions while towing with anything more than stock power. I did mine and it is slipping again so I'm always being careful and keeping the revs up while towing hard. Bummer! I see a triple disk in my future!

If you add more power you must do something with the tranny and even at stock power it would be nice. A Smarty is so easy and makes so much difference you'll never go back. Then the tranny is a must, but you don't have to go extreme. A solid shifting valve body with circulation in park would be nice. A high strength second gear band can be had from Chrysler and they are way stronger than stock (my tranny guy said he sees a lot of stock ones stretched). A good torque converter is a must. And a new flex plate would give some piece of mind as well as a new input shaft if you really are willing to spend a bit and if you want to prepare for a bit more power with very solid shifts.

When you are done and all back together you can add a lockup switch for mountain use. It makes the tranny 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.

I know you said you probably won't add power but consider a Smarty. It makes a lot of difference in the driveability by making the throttle response better with more power. It will also improve the mileage. No need to go extreme with it though. You can run it on 60 HP or 90 HP and you'll love it. Just keep the revs up when pulling to keep the EGT within reason. Of course gauges are part of the package. It never ends!

 

When you are done and all back together you can add a lockup switch for mountain use. It makes the tranny 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.


Do you have the instruction for the lockup switch?

 

DF,

Do some searching and you'll find way more than I could post. Be sure to find the exact year and follow the directions.

Search for mystery switch or TC lockup switch

You'll end up with a very simple wire to the tranny that you ground with a convenient switch. Mine is a mini toggle switch mounted on the shifter arm where I can reach it with a finger very easily.

 

Be careful in using a lock up controller or lock up switch with a stock input shaft.. I have heard stories of people locking the converter and the input giving up the ghost when it locks.. the Input shafts behind these motors are notoriously fragile..

 

Seems like you are going about this a kinda odd route.

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

The VB is different, also there are a few minor differences depending on the trucks years in the 47RE. As far as internals go, the 48RE has 6 pinion planets instead of the 5 pinion planets in the 47RE. This is desirable, but in your application probably no overly important. The 48RE fwd planet has a different spline count requiring a different clutch pack than the stock 47RE. All of the shafts are the same, as are the bands, servos, ect.

So, basically, what I would do is order a rebuild kit for the 47RE (new clutches, steels, seals, gaskets), a transgo shift kit (or complete VB), new, upgraded converter, and I would HIGHLY recommend a billet input shaft and you should have a good, solid towing trans. Now, if you plan to run an exhasut brake, add the BD pressurelock on the build.

 

Ding, ding, ding we have a winner ^^^^^^

 

If you are going to build a trans, I would go with the 48RE. It is stronger and will work in your truck just fine.

 

anyone know where to find a good rebuildable core

 

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. Use ALL of the 48 parts, dont mix/match them or you run into clearance problems. Use the 48 pump as well, but be sure the convertor you use is for the 48RE. The only 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.

I do thses types of conversions all the time and they work excellent. Oh, the input shaft? The 46, 47 and 48 are all the same. While its being converterted, replace the input with a billet.

 

I've got one in my garage out of 03 HO (48RE)

 

It should not be locked during the 1-2 upshift, but the 3-4 upshift is no big deal. I don't like shifting at all when locked. And you should NEVER race while locked or lock it while brake torquing!!!

Common sense goes a long way here and with prudent use it is a nice modification that makes the truck drive better in the mountains.