Hello!

What year did they replace the TF727 with the 4 speed auto? Also, what model is the 4sp? Is it the same tranny that was put in later trucks, and if not, when was that changed?

Also, IIRC, '91 was the first year for intercoolers...is this right?

I'm asking 'cause I'm working on putting together a timeline for changes to the Dodge diesel line-up..actually, I'm going all the way from '89 to present, so this probably won't be the last question I ask.

Any help would be appreciated. Thanks in advance!

 

I think most of the stuff you are looking for can be found on Dave Fritz's site. dodgeram.org

 

Thanks! I haven't been over to Dave Fritz's site in a long time...he's done a heckuva job with it. Looks like the intercooler was added for the '91 model year.

Unfortunately, I couldn't find a date for the switchover from the 3 speed to the 4 speed. Did I miss it, or does anyone know?

Thanks!

 

I believe the 91.5 and up model year brought in the intercooler and the A518 (727 with OD)
In 94 the tranny change to the 47RH and added the lockup torque convertor to the system.

Bob.

 

My buddies 90 has the 3 speed and no intercooler,my 93 has the 4 speed od unit, if that helps??

 

Digging up an old post

Thank you all for your comments; I apologize for not replying earlier; things with school got extremely busy.

I do have a couple more questions to ask, although this may not be the appropiate forum.

First, going by Dave Fritz's site, the 47RH sounds like a mechanical tranny. Is that right? If so, how was the TC lockup controlled? Also, when did the 47RE electronic tranny replace the 47RH?

I'm almost done with the history portion Thank you again!!!

 

First gen trannys do not have a lockup converter. They do have a button so you can lock out overdrive. I'm sure someone else can tell you more.

Paul

 

As I understand the 46RH came out in 91 and the 47RH came out in 92. The 47RH is a heavy duty version of the 46Rh used exclusively for the diesel truck applications.