Well. Tryin to decide what tranny im going to look for. auto 5 or 6spd. its gonna be a used 03 probably so the chances of finding a 48re are pry slim. But my 47 in my 99 is runnin 150k with no problems. So thats not REALLY a consern here

What im lookin for is the RPM and cruising speeds. my 99 runs me around 70mph at 2000 rpm. Nets me about 21 or so in mileage

What do the new trannys run? Since the rear is a lil shorter?

I dont mind the shifting i dont think haha. Care about reliablity but in the long run the current auto is lastin for ever and this one will pry be bombed down the road anyway

Any ideas?

 

It is my understanding that the 47RE and the 48RE have the same gear ratios

2.45, 1.45, 1.0 and OD 0.69

Remember the ultimate RPM vrs speed also depends on your diff ratio and tire size.

Hope this helps

cheers f

 

Mine runs about 2150RPM at 70MPH with the 48RE and 4.10s.

 

sounds about right then. Guy I was talkin too. Hes takin the Big Rig driving class where I Take my Diesel Tech. He said he ran about 2200 in 6th with his so im like Thanks for hte info guys

 

I have the 48RE and 3.73 gears, I run 1950 - 2000 RPM at 70.

-Sam

 

same here as sbutter...just a cooter hair under 2k at 70mph
later, dustin

 

Southern folk. I love it.

47RE, 3.73, 315s

60mph 1550rpms
65mph 1700rpms
70mph 1850rpms
75mph 1950rpms

 

Awesome Good info. Ive got it knocked down to 2 now. Either the Auto or the 6spd. Ive tested all. Over all i think the auto might win out. The 5 speed was a lot of shifting and no fun. The 6spd was a lot of shifting but, you got that extra brunt there. One thing i found myself doing was jumpin from 2 to 4 to 5 with the 5 spd. And from 2 4 6 with the 6 spd which made it a lil better. Another thing i found with these trucks that isnt true with the lil car standards in on hills. I hated trying to do that but with these i can put her in one and leave a foot on the brake and another on the clutch and she wont die! I love that. Good stuff there. Just can decide. Mileages are seeming to be the same. But theres a lot more 6 spd used 3rd gens out there than autos!. I hate complications

Oh yeah. Whats everyone think of that shift pattern? Think it s hard on the trannys?

 

Try this, it's very good.


http://www.klenger.net/dodge/general...calculator.xls

 

According to the worksheet,my speedo must be off. I actually see 70 at a cooter hair below 2100 rpm. w/245/75/16 and 3.55 gear. Southerners...gotta luv us.

 

At 70 MPH I'm right at 2000 RPM with the 6sp. manual. I like the manual for towing the 5er, and have the Jacobs Ebrake which I enjoy the benefits of very much. If I'm running empty highway at 1950 RPM (68 MPH) I will get a manually calculated 18.5 - 19.0 MPG; around town (most of my driving) averages out at 16.5 to 17.3 depending on how many start/stops I have to make. I'm probably the odd one out here, but I use all six gears, even running empty.

 

Try using the manfactures revs per mile instead of the generic tire size. When I plug in 601 revs per mile for the BFG 315's as opposed to 315X70-17 the difference is a whopping 2 MPH! Play with the numbers and have fun!!

 

Jerry R

RE: Try this, it's very good.
http://www.klenger.net/dodge/genera...-calculator.xls

The spreadsheet looks great. The nos jive with my calculations except yours are variable. I have the 47RE and 48RE numbers in KM/H if you are interested. Of course the spreadsheet could accomadate the Ks or Ms .
Good show
Frank B

 

If a H.O. its eaither a six speed or a auto.There is not a five speed.Mine is 2300 or so at 70.Six speed and 4.10s