At a loss, transmission or ...

[Shoda]

I was towing a fiberglass boat with my daughter's 04 Ram 1500. It has a Jasper 5.7 Hemi and formerly had a 46RFE. The transmission died about 100 miles from home. Dealer said it was the cooler and the transmission. I replaced both of them, transmission is now a 545RFE and the cooler is high flow/super cooler. Could not get the truck past 3rd gear. Replaced the PCM and did a complete relearn. Still couldn't get it past 3rd gear. This time, it threw several new codes, so I replaced the throttle body. No codes, no limp mode light, no real power in lower gears, still won't shift past 3rd gear...

Before I junk this one and start over, any suggestions other than throw more money at the issue? I'm already over $4000 into repairing a $7500 truck for my baby girl...

 

[HemiLonestar]

If that 04 came from the factory with a hemi, it had a 545RFE to start with. No such thing as a "46RFE"; 46RE yes (not available that year) and 45RFE yes (also not available that year). All 2003 to 2008 automatic hemis came with the 545RFE. Before you throw more parts at it, what codes were you getting? Were any of them before your dealer visit?

 

[Shoda]

For some reason, the previous owner put the 45RFE on the aftermarket Jasper 5.7 (previous post of 46RFE was a typo that I didn't catch)...

I was receiving all sorts of codes from the dealership. I replaced the PCM and that cleared all of them except the TPS codes. I replaced the throttle body since the TPS is part of the throttle body. The only code now is the P0700. I am wondering, at this point, if the torque converter is somehow not set right or if the second solenoid is bad in the reman transmission.

 

[HemiLonestar]

You should have another code with the 0700 (that's just a general trans fault); is there no accompanying code?
If the TC wasn't set in right you shouldn't have been able to bolt the trans back in correctly. When you say "complete relearn", do you mean the factory actual quick learn with the proper scan tool?

 

[Burla]

Did you use the valve body from the 45rfe? If so it could be the check valve locations. Also, do you know what color the solenoid pack was?

The first one below is the later model valve body, 2009-2010 plate stamped 52120004A.
2011-later plate stamped 52120004AB.

 

[Burla]

As far as shifting rule of an rfe there is one absolute, "If you are not sure what valve body you need for any RFE transmission just install a seven-ball separator plate with a white solenoid and you can’t be wrong." So even though the grey ones may have better or latest quality, the rule above can play in any rfe.

It weird because even though newer rfe's have more gears, they have less check ball locations, but they still follow the rule above about 7 check balls plus white solenoid plays in any rfe.

 

[HemiLonestar]

It weird because even though newer rfe's have more gears, they have less check ball locations, but they still follow the rule above about 7 check balls plus white solenoid plays in any rfe.

Only have more gears due to programming....even if you put say a 68RFE into an older truck, it'll still behave like a 545 because of the software running it.

 

[Fishstickz]

Only have more gears due to programming....even if you put say a 68RFE into an older truck, it'll still behave like a 545 because of the software running it.

I actually didn't know that. I know swapping a 68 behind a gasser would probably be a bad idea since it's meant for the low rev-high torque of the 6.7 cummins (and would probably take a bit more work to swap anyways). But what about the 66RFE? I see most of the high performance guys talking 46rh, 4l80e or NAG1 swaps without mentioning a 66RFE swap so I'm sure for whatever reason it's just not worth the trouble of swapping, whether that be due to the same low input capability of the 545 or just because of the RFE staple of horrible performance shifting. But I've read the 66 has some of the innards of the 68, which I would imagine there would be SOME SORT of increase in the max power input even if it's just negligible.

Also since the RFE is just about completely computer-controlled, I wonder what it would take to program in different gear ratios/new gears completely, if thats even possible. I imagine it would be, but most likely well beyond the scope of just about everyone

 

[HemiLonestar]

Even with the heavier internals the programming is the same, that was this transmission's major downfall, not to mention it's horrendous parasitic loss. On average stock 345 bhp translates to 260-270 whp. 46RH (the good old A518), 4L80E & NAG1 (haven't seen one of those in a Ram yet) are used/talked about more because they're **** strong even in stock form.
Way back in the day (I wish I had saved that post) an engineer had calculated that the 545RFE was theoretically capable of like 15 fwd speeds and 2 reverse speeds. This would require software/programming at the factory level to make this a reality. TCM custom tuning has to live & work inside whatever the OEM framework is. Superchips figured how to custom tune the 545RFE a long time ago, but it doesn't change the fundamental fact that it will always have 3 regular fwd gears, 2 OD gears, a kickdown only gear (2P) and a reverse gear. I'm sure someone figured out how to make a controller that could change all that but it wouldn't function within the electronic architecture of the vehicle.
All of this is why the ZF transmissions are getting more popular to retrofit despite the up front costs and difficulties. I had already been long term planning this but recently talked to a guy up in Canadia running a 2004 with a 6.1 based stroker and an 8HP70. The extra gear split and retaining the double OD for at least some illusion of fuel economy is very appealing lol.

 

[Fishstickz]

All of this is why the ZF transmissions are getting more popular to retrofit despite the up front costs and difficulties. I had already been long term planning this but recently talked to a guy up in Canadia running a 2004 with a 6.1 based stroker and an 8HP70. The extra gear split and retaining the double OD for at least some illusion of fuel economy is very appealing lol.

I hope to see more guys swap to the 8 speeds. Its pretty clear that the RFE simply can’t be abused no matter how many beefed up parts you stuff in it. With the things Sound German Auto is doing I’m hoping the 8 speed swap and the abundance of used 8HP70s out there it will start to be more common. I love the 46rh but I think I’d love having double the amount of gears more lol



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[HemiLonestar]

I hope to see more guys swap to the 8 speeds. Its pretty clear that the RFE simply can’t be abused no matter how many beefed up parts you stuff in it. With the things Sound German Auto is doing I’m hoping the 8 speed swap and the abundance of used 8HP70s out there it will start to be more common. I love the 46rh but I think I’d love having double the amount of gears more lol



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Speaking of SG, Russell is messing with a 2010 Hemi Ram as an engineering mule. And I quote:
"Had an interesting idea that so far is looking like it will pan out. I may be able to spoof the RFE enough to not need to reprogram the ECU at all for the 8hp swap in the RAM. Also found what I think is the trailer brake connectors under the dash with Power and ground and CAN. And Brake input maybe. I am thinking that wiring will come inside through the shifter cable grommet since it is no longer needed. Also looking at an idea to use the column shift and remote mount the floor shifter under the dash. I have some other ideas for this as well.
Measurements look close enough that I may get luck on the installation. I should start in the next couple of weeks."
I asked if this would work for CAN only or pre-CAN as well and his response is "I don't see why not". As I am not in a hurry to do this swap, the way things are looking if I wait long enough Russell will figure it out and make my life easier lol. I got alot of tips from a guy up in Canadia on the HTC forum who did it with a 6.1 based 392 in a 2004.