I was talking to a tech at my dealership about a couple of problems I'll be taking it in for next week & while talking about the trans he mentioned that he was told at a tech school that the 48RE is really a 5 speed auto, there is a software program that keeps it from engaging!!

He says that he doesn't know why they did that but there is an extra gear in the trans that isn't being used!!

What's up with that?????

 

If you think about it, it could have five gears. Stock it has 1-3 then applies the overdrive of 0.69:1 for fourth. It could have 1st (2.45:1), 1st +overdrive (1.69:1), 2nd (1.45:1), 2nd +overdrive (1.00:1) , 3rd (1.00:1), and 4th (0.69:1). Since 2nd + overdrive is the same as 3rd this would make it a 5 speed. With some different gearing it could be a 6 speed.

 

I think that's pretty close to how the new Ford Torqueshift get's it's 5 speeds.

 

Think he could be talking about the 5-45RFE tranny used behind the 5.7 hemi?

 

[quote author=BIGCUMMINZ link=board=20;threadid=21428;start=0#msg201391 date=1067125355]
im sure if it was a 5 speed dodge would make it a 58 re. Why would they say a 4 speed auto, when a 5 speed is better. if you dont count the od them its a 4 speed right? ???
[/quote]

well if a 4 speed is good, a five speed better than the 6 speed must be the best RIGHT????? (sorry but you set it up tho....) ;D
Don't count the lockup as a shift.

 

On Page 21 - 312 of the 03 Service Manual explains to us that the 48RE is a 4 speed transmission. It's really a 3 speed with an overdrive unit built into to the rear section to provide a 4th gear. D/C's automatic transmissions have been to a large extent based on the Torque-Flite and Power-Flite that I rebuilt many of in the late 50's & 60's. (Yes I am an old F@*t) Of coarse there have been constant upgrades in parts design, quality, lock-up converters, overdrive units, etc.

I think they could stand more improvements to hold up to the Mighty Cummins. MUCH more improvements if the Cummins were turned up to the H.P. it was designed for. Talk about "Bombing" the CTD to boost power and the first thing you hear is "upgrade the weakest link, the automatic trans. FIRST".
Not downing the 48RE, - overall it's a good transmission. .... for a 4 spd. automatic.
Think I'll stay with my 6 speed manual.

Just my honest opinion. ;D

 

The gearing I quoted was for the 48RE. It only shifts into OD when the main part of the transmission (a 3 spd) is in 3rd gear. The only reason I can see why it couldn't use OD for intermediate gearing is perhaps the OD unit wouldn't hold up to the torque (which would be 2.45 times higher in 1st than it is in 3rd). Other than that, it has the gearing to make it a 5 spd.