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03:05:01 - 05/03/2024
V8 Dakotas
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dctech
Dodge Dakota
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9/30/2002
20:49:37
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 Subject: 45rfe/545rfe
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If you are looking for quicker, harder shifts on your 45fre/545rfe(same trans.), try this. Disconnect your line pressure sensor(right-hand side at rear of transmission). Your TCM will not see a line pressure reference and will substitute its own figure using inputs from TPS, MAP, CPS, etc. The actual line pressure will be higher thus actuating clutch packs faster (there are no bands in these transmissions)and giving you faster harder feeling shifts(like a shift kit but not really). We tried this at tech training last week. It did not set a MIL, DTC or one trip failure, in fact while we observed the line pressure sensor value on the DRB the TCM substituted its own value and voltage, BUT with an actual gauge hooked to the sensor port the pressure was higher. I haven't tried this on anything but the Liberty we were working on at tech training so I would be interested in any comments from anyone who tries it on their own. Good luck.
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Ian
Dodge Dakota
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9/30/2002
23:20:35
| RE: 45rfe/545rfe
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DCtech...in regards to my 45rfe would it only be a matter of a simple flash to convert it into a 545rfe, if so are there any mpg or performance gains I would realize by doing this?
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dctech
Dodge Dakota
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10/01/2002
18:00:43
| RE: 45rfe/545rfe
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Message:
Yes, a simple flash would convert your 45rfe into a 545rfe if the flash is available for your vehicle, give me the year and i can check. There wouldn't be any performance gains but decreased fuel consumption is likely because you are adding fifth gear(1st > 3:1, 2nd > 1.67:1, 3rd > 1:1, 4th > .75:1, 5th > .67:1 , 2nd prime > 1.5:1, Rev. > 3:1). As you can see there isn't a large difference between 4th and 5th but there is a difference which will drop highway rpm.
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2THEXTRM
GenIII
10/01/2002
18:05:56
| RE: 45rfe/545rfe
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Message:
I have a 2002 that I would like to add that 5th gear to reduce my rpm at 65-75mph on the highway. Any flashes for 2002 4x4 with 45rfe? Thx.
Flowmaster cat back, Air Raid w/homemade TB connect, Poweraid TB Spacer, Splitfire Plugs
3 inch body and 1.5 Block Lift, 305 70-16 X-Terrains on AR Terons
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CW
GenIII
10/01/2002
19:13:25
|  RE: 45rfe/545rfe
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Message:
2thextrm: All 2002 and up have the fifth gear flash.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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Rob
GenIII
10/01/2002
19:31:20
| RE: 45rfe/545rfe
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Message:
Thanks for the info "MAYBE" I'll try that tranny thing.Where dou you work DCTECH?
 1NICEDAK
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Ian
Dodge Dakota
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10/01/2002
20:09:31
| RE: 45rfe/545rfe
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Message:
I have a 2002 2wd quadcab, it was my understanding I simply have a dual ratio 2nd gear and that the 545rfe actually has a fifth gear as compared to mine only having a final gear of four
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2THEXTRM
GenIII
10/01/2002
21:09:11
| RE: 45rfe/545rfe
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Message:
CW,
Thx for the input, that is strange cuz the rpms are at just over 2K @ 65mph which is the same as my 2001 was before larger tires. My wifes truck was delivered to the dealer 8/01 and we purchased it 7/31/02, is it possible that it doesn't have the fifth gear flash?
If it does, then I can say the "fifth gear" does not give you lower rpm's at highway speeds and no change in mpg(14-16 consistently) since I can compare everything to my 2001 CC Dakota w/3.55's that was actually getting better mileage stock(16-18 mpg) and now nearly the same with 33's as my wifes RC Dakota 4x4 with 3.55's, stock height/width 18's, Airraid Intake, Vortex muffler using stock pipes, Autolite 3923's and tonneau cover.
Go figure, hope this new tranny flash worked for someone else. What kinda mpg is everyone else getting with a 2002 RC 4x4 with 4.7, 3.55 gears?
Flowmaster cat back, Air Raid w/homemade TB connect, Poweraid TB Spacer, Splitfire Plugs
3 inch body and 1.5 Block Lift, 305 70-16 X-Terrains on AR Terons
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CW
GenIII
10/01/2002
21:39:21
| RE: 45rfe/545rfe
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Message:
Going from .75 to .67 is a pretty small change. The flash wasn't designed for milage it was for a a exhaust noise at a certain RPM. The reson you may not notice the difference between 2 trucks is that the tach could be out that much between the two. We are only talking about 200RPM.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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Horbedarn
*GenIII*
10/01/2002
23:12:16
| RE: 45rfe/545rfe
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Message:
I was wondering if the flash is available for my transmission. I have a 2000 Dakota. Thanks for any info.
2000, CC, SLT, 4x4, 4.7, 3.55, Auto
MBRP Dual Exhaust Cat-Back, JBA Headers, 72mm TB, 4" Z-Tube
3923's, 180 T-Stat, IAT Adjuster
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MidnightMagic
Dodge Dakota
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10/05/2002
13:04:16
|  RE: 45rfe/545rfe
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Message:
i will try out the line sensor thing in a few, also if they have the flash for a 00 4.7 im there!
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CW
GenIII
10/05/2002
13:17:52
| RE: 45rfe/545rfe
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Message:
It is available for all 2000-2001.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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dctech
Dodge Dakota
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10/05/2002
13:19:23
| RE: 45rfe/545rfe
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Message:
The best way to find out what flashes are available four your controllers, pcm tcm, is to go to your local dealer and have them connect your truck up to the mds, read your part numbers and check for available updates. It is the only sure way to find out.
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Lab Rat
GenIII
10/05/2002
15:51:42
| RE: 45rfe/545rfe
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Message:
I like to add my .02 to this. From everything I've seen, the 45RFE is a true five speed, hence the "F", but only uses four gears with different shift patterns. Example:
Upshift sequence: 1,3,4,5
Downshift sequence: 5,4,2,1
5th gear remains the same no matter what. It doesn't make sense that a computer flash could cause a physical gear change in the tranny, either.
Based on this, possibly a flash could yield the full 5 spd capability; i.e. up=1,2,3,4,5; down=5,4,3,2,1.
Just something to think, as I said its just my opinion.
LR
Gibson Dual Sport, AirForce One air intake, Jet II, Jet TBS, 180 stat, IAT, TPS, no viscous fan, Lakewood traction bars, "Wilson" antenna ball...when are we gonna see some real parts??!!
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slow2dak
Dodge Dakota
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10/05/2002
17:18:07
|  RE: 45rfe/545rfe
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the 45rfe stands for as follows:
4: four speed auto
5: torque rating
r:rear
f:fully
e:electronic
these are all stated in the 2002 AN Transmission service manual at my dealership i work at here in texas. there are 2 second gears. from a dead stop you have a 1-2-3-4 shift pattern. on downshifts at speed, say 4th to 2nd, it shifts into "second prime", which had a higher ratio than the 2nd on upshifts.
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CW
GenIII
10/05/2002
17:46:08
| RE: 45rfe/545rfe
IP: Logged
Message:
Fine, I give up, think what you want. They are a true 5 speed with a alternate second gear. 1,2,alt2,3,4,5 with the new flash. It's a double O/D like DCtech showed.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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Midnightmagic
Dodge Dakota
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10/05/2002
19:40:57
|  RE: 45rfe/545rfe
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Message:
i tried it and its no use, the tranny does shift harder ie chirps second but you have to go from d to 2 then back to d, otherwise it will shift extremely quick from first to 3rd and not go into 4th. even under hard acc. and will not down shift once in third. but this does not mean its not useful.... maybe they will come out with a interceptor like the ones for the cavaliers, adjustable line press.. maybe...
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handi2
GenIII
10/05/2002
22:26:46
| RE: 45rfe/545rfe
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Message:
My 02 QC purchased in November of 01 as a 2002 model shifts 5 times in forward gear.
http://photos.yahoo.com/handi254310
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dr0p0ff
GenIII
10/07/2002
09:49:49
| RE: 45rfe/545rfe
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Message:
the only way i've heard of it is the way that CW is discribing it. would be kinda cool to be able to program in the ratios and shift points i want
Keep On Truckin!
Sgt G
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dctech
Dodge Dakota
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10/07/2002
19:18:02
| RE: 45rfe/545rfe
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Message:
To clear up the second prime or alternate second gear issue for those who of you who don't know why it is there, the only reason they use this gear ratio is because of the clutch packs being applied. During every shift sequence one clutch pack will stay applied ie. 1st to 2nd underdrive clutch stays applied, 4th to 3rd overdrive clutch stays applied, etc. etc. During a 4th to 2nd downshift (hard acceleration) there has to be 2 clutch packs released and 2 clutch packs applied,4th gear uses overdrive clutch and 4C clutch, 2nd gear uses underdrive and 2C clutch) this does not create a nice smooth quick shift so chrysler engineers noticed a gear ratio close to second (.17:1 difference)) that used the underdrive and 4C clutches. Now they only have to release 1 clutch and apply 1 clutch making for a better 4-2 downshift. This is the only time 2nd prime gear is used.
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CW
GenIII
10/07/2002
21:49:34
| RE: 45rfe/545rfe
IP: Logged
Message:
If both clutches were to release you could have a momentary free wheel. Making for a nasty shift.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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Ian
Dodge Dakota
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10/07/2002
22:41:19
| RE: 45rfe/545rfe
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Message:
can somebody please clear this up...I believe the 02 has 4 gears with a dual ratio 2nd gear while the 03 actually has 5 gears..is this not correct?
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CW
GenIII
10/07/2002
23:06:21
| RE: 45rfe/545rfe
IP: Logged
Message:
No your '02 has the same programming as the '03
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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dr0p0ff
GenIII
10/08/2002
14:14:07
|  RE: 45rfe/545rfe
IP: Logged
Message:
Have any of you guys tried driving around with the line pressure sensor disconnected? i'm unclear (after trying it for sh!ts and grins) if i did it the way dctech was explaining it. just disconnect it right? i did. i got a very nice firm 1-2 shift.. but everything else sucked a big fat one. under light acceleration the clutch would slip and allow the rpm's to pulse up and the truck to lose power. if i punched the throttle and the truck should downshift to accelerate, it just threw itself out of gear and the rpms screamed up to 6500. (mustang next to me hauled ass away because he thought i was reving at him.. lol) truck would sit in neutral for 4-5 seconds inbetween R and 1. what gives? i was really hoping this would work. (makes me want to play with a varisitor though) i've got my service manual here and i'm studying the hell out of the 45fre section to find out what else could be done to fool the TCM into giving me what i want.
oh.. is there anything different from year to year that would cause this trick to work on one truck and not an older/newer one?
Keep On Truckin!
Sgt G
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CW
GenIII
10/08/2002
14:30:35
| RE: 45rfe/545rfe
IP: Logged
Message:
Basically all that sensor does is report what is happening in the trans. I didn't figure pulling the sensor would work. I don't have a auto to play with though. I am willing to bet if you took the accumulator springs out and blocked the pistons that it would shift firmer.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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for7v8
Dodge Dakota
JOIN HERE
10/08/2002
16:02:39
| RE: 45rfe/545rfe
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Message:
To any of you DC techs. Do you know how long the flash has been available? Had mine reflashed a month or two ago.
Thanks...
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dr0p0ff
GenIII
10/08/2002
17:12:57
| RE: 45rfe/545rfe
IP: Logged
Message:
thanks CW
Keep On Truckin!
Sgt G
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CW
GenIII
10/08/2002
20:02:25
| RE: 45rfe/545rfe
IP: Logged
Message:
for7v8: Yours should have the new flash.
4.7 HO, CW style
2001 4.7 5sp 3.92 LSD
Ported 68mm TB, IAT adjuster, 3" flowmaster cat back, TPS @ .76V, 4" Z-tube, Roadmaster active suspention, Removed Third cat, Electric fan Convertion, HO cams, Robert shaw 180 therm, HO intake manifold.
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Todd Bouton
Dodge Dakota
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10/09/2002
11:52:16
|  RE: 45rfe/545rfe
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Message:
CW,
you wrote:They are a true 5 speed with a alternate second gear. 1,2,alt2,3,4,5 with the new flash
CW, thats 6 gears!
So far, it seems that there are 4 forward gears, like if you WOT form a start, it would shift 3 times(you'd be in 1st!)making it 4 forward gears.
Thats why they call it a 4 speed, now I know all you with this tranny want to call it a 5 spd, but it has 4 different forward gears
CW, dctech is saying that there's really only 4 forward gears at once, a 4 speed. Like has been said, if you go up and down, then there's 5 different gears, with 4 consecutive forward gears.
Otherwise they'd be the first to call it a 5 speed auto.
Mine has 5 forward gears though.
Flame suit on!
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BlueBayou
Dodge Dakota
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10/10/2002
10:55:33
| RE: 45rfe/545rfe
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Message:
Todd:
They do call it a five speed.
http://www.jeep.com/grand_cherokee/power/details.html
Well, after the flash!
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Texas Todd
Dodge Dakota
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10/10/2002
11:10:07
| RE: 45rfe/545rfe
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Message:
Blue,
Thanks for the link, I read thru it.
I'm no tranny specialist to say the least, don't even own an auto, either car or truck. However, by reading it, it still seems there are ONLY FOUR forward gear ratios.
It was explained quite well by 'dctech' how the beltless tranny has to have this kind of arrangement,
Call it what you want-it's 4 forward gears.
Todd
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