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Dodge Dakota
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2/16/2006
21:31:39

Subject: 45RFE and 545RFE
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I know the discussion has been around about the 45RFE and 545RFE being the same except for programming but has anyone actually had their Dakota 45RFE upgraded to a 545RFE at the dealership by a flash.

I ask because I noticed Jeep had a flash for their 1999 and 2000 45RFE being able to get the 5th gear.

http://www.wjjeeps.com/tsb_list.htm#1802501
-------------------------------------

1802501 - 45RFE AND 545RFE SHIFT QUALITY ENHANCEMENTS FOR THE 2-3, 4-5, AND 5-4 SHIFTS / ADDITION OF 5TH GEAR RATIO
Date: 10/15/01 (supersedes 210900 dated 09/15/00)

Model year(s): 1999-2001

Description: This bulletin involves selectively erasing and reprogramming the Transmission Control Module (TCM) with new software: 99-01 WJ (PN 05019701AC Ver 9.3 ), and requires reprogramming of the Powertrain Control Module (PCM) for the 1999 and 2000 Grand Cherokees (with calibration 99Cal20 (1999) or 00Cal17 (2000).

NOTE: THE 2001 GRAND CHEROKEE DOES NOT REQUIRE REPROGRAMMING OF THE PCM AS IT IS ALREADY AT THE CORRECT CALIBRATION LEVEL.

NOTE: WHENEVER A PCM OR TCM IS REPLACED OR REPROGRAMMED, THE SOFTWARE OF THE PCM MUST BE VERIFIED AS HAVING THE LATEST REVISION LEVEL.

Details: Some vehicles may exhibit one or more of the following performance conditions:
1. A harsh 2-3 upshift causing a powertrain clunk or shudder when accelerating.
2. A harsh 4-5 upshift (01 Grand Cherokee only).
3. A harsh 5-4 downshift (01 Grand Cherokee only).

NOTE: THIS REVISION TO THE TCM SOFTWARE ADDRESSES THE ABOVE SHIFT QUALITY CONDITIONS FOR ALL VEHICLES AND ADDS A FINAL GEAR RATIO TO THE 1999 AND 2000 MY GRAND CHEROKEE TRANSMISSION ONLY. (2001 MY GRAND CHEROKEES ALREADY HAVE THIS UPGRADE.)

NOTE: Owners of 1999-2000 models who want to verify if they have the 5th gear ratio or not can check their engine RPM at 70 mph. Vehicles without the upgrade will have an RPM of around 2400-2500 while those having the new 5th gear ratio will be very close to 2000 RPM.




jayb
Dodge Dakota
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2/20/2006
15:53:41

RE: 45RFE and 545RFE
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you can add gears to a transmission by programming it.



jayb
Dodge Dakota
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2/20/2006
15:55:44

RE: 45RFE and 545RFE
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*CANT



GraphiteDak
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2/20/2006
15:58:20

RE: 45RFE and 545RFE
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When it's got 3 planetary gears, no bands, and something like 8 possible forward gear ratios you can :)



Kowalski
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2/20/2006
16:05:04

RE: 45RFE and 545RFE
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jayb is mistaken, GD is correct. I've only heard of it actually being done in the jeep though, not sure if Dodge has reprogammed too.

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davec
Dodge Dakota
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2/20/2006
16:58:48

RE: 45RFE and 545RFE
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I heard 6 gears by reprogramming...that comes from Chrysler. The 45RFE is actually a 5 speed auto. It has 2 second gears. One for normal upshifting...one used in kickdown. I don't remember the ratios but the kickdown is slighty deeper I believe.

I also heard 100 horses from the 4.7 by reprogramming...also from Chysler...don't ask, I don't know.

Dave



GraphiteDak
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2/20/2006
18:27:44

RE: 45RFE and 545RFE
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The part about the tranny is true. But 100 horses LOL!!!


6 is the total USED if you count the alternate downshift 2nd gear. But what I meant was they said there WAS 8 possible forward ratios. But not all are useful.

The 5-45RFE works by what combination of planetary gears you apply.




caulk04
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2/20/2006
19:01:47

RE: 45RFE and 545RFE
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I asked my dealer about it, they told me there are no TCM flashes in the system for my 45RFE. I'm in pretty good there, they don't screw with me.

I was really hoping there might be one, but there isn't. :-/

'02 CC 4x4 4.7 HO
http://www.cardomain.com/ride/2147050 <- Check it out!

GraphiteDak
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2/20/2006
21:08:05

RE: 45RFE and 545RFE
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Actually. To tell you the truth I wouldn't worry about getting the extra ratio which really isn't much different from 4th anyway.


I kind of wish mine would use 4th more often at times when I'm towing. When it does use it and stay there it's like a sweet spot (and it's NOT just the converter unlocking). But there's no way to manually MAKE it use it. If you hit the OD button it drops to 3rd.



Lurkin
Dodge Dakota
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2/21/2006
08:40:33

RE: 45RFE and 545RFE
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From what I've seen, and recall, of the ratios, the 45RFE has 3rd gear as 1:1, with a single OD gear (4th). These are not counting the split 2nd gear as different gears.

The 545RFE also has 3rd as 1:1, with 4th and 5th as OD gears. 5th does end up being a deeper OD though then the final 45RFE gear.

In other words, IMHO, 545RFE may get a bit better milage on the highway, depending on the number of hills and load, but probably wouldn't help you Speed Racers too much.

I'd originally heard about an "upgrade" 45RFE flash a couple of years ago, but once I saw the info above, I decided I didn't care too much given my use pattern.



Josh
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2/21/2006
17:59:03

RE: 45RFE and 545RFE
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This is a Jeep thing, so you may have to visit your local Jeep service dept, since the Dodge pukes are probably in the dark on this one.
Even though you may have the same transmission and engine combination as the 1999/2000 Jeep, they still may not be able to make that change for you if your PCU and TCU are different than the Jeep's.



Joe.C
Dodge Dakota
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2/22/2006
14:46:14

RE: 45RFE and 545RFE
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The or both the 45RFE and 545RFE actually true 3 speed transmissons. Look at the gear ratio's for instance. Both 3rd gear is 1.00:1. So when when you lock out your O/D both transmissons will gear up to 3rd.



Kowalski
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2/22/2006
18:38:35

RE: 45RFE and 545RFE
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Um, those of us who grew up with "true" three speed autos (like the 904 & 727) that were before overdrive autos became common might not agree with that...

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olsarge
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2/22/2006
20:55:04

RE: 45RFE and 545RFE
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This ain't gonna get solved until someone gets the flash and reports back.



STS
Dodge Dakota
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2/23/2006
15:40:36

RE: 45RFE and 545RFE
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Then what else would you call it??? Your saying that 4th and 5th are real gears?



Kowalski
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2/23/2006
15:41:21

RE: 45RFE and 545RFE
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I'd consider it solved UNLESS someone gets the flash; like I said earlier, I've only heard of it being done in the Jeep.

Lead, follow, or get out of the way

GraphiteDak
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2/23/2006
16:50:13

RE: 45RFE and 545RFE
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Reading back I heard that DC added the 5th to the JEEP to reduce a vibration at a certain RPM while driving in the highway. And doing that did the trick.

Makes me think it's all programming.





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