545RFE vers.45RFE

[Dreamcatcher]

I am looking for everyone's opinion on these transmissions. I just bought yet another wrecked RAM with a 5.7 (3rd one I have gotten). I went to pick it up and found out it is 4 wheel drive and not a 2 wheel drive. It is an 05 with just over 100K miles. I read that this transmission can be used with just a tail shaft swap. I think the only difference is 5 speed vers. 4 but the gear ratio is a bit higher in the 45RFE. Just looking for opinions as it might be cheaper and easier to keep this transmission instead of buying a 545.

 

[kb67mopar]

The 45RFE is the same transmission. I have a transmission controller in my garage from an 02 Jeep that will give that 45RFE its 5th gear. The only difference is in the electronic control. I had an 02 Dakota with the 4.7 and 45RFE. Took the jeep controller and put it in for 5th. With my gearing I ended up losing MPG and took it back out...so now it sits in my shed. So FYI if one so desired I am thinking you could grab a 03 wiring harness and run this TCM and actually have a stand alone controller for the 545RFE.

 

[383man]

The 45RFE is the same transmission. I have a transmission controller in my garage from an 02 Jeep that will give that 45RFE its 5th gear. The only difference is in the electronic control. I had an 02 Dakota with the 4.7 and 45RFE. Took the jeep controller and put it in for 5th. With my gearing I ended up losing MPG and took it back out...so now it sits in my shed. So FYI if one so desired I am thinking you could grab a 03 wiring harness and run this TCM and actually have a stand alone controller for the 545RFE.

Yep kb67Mopar is right as they are the same trans they give it the extra gear by turning on a differnt set of clutches for the fith gear. I cant remember for sure but I think they turn on second and fourth clutches to get the fith gear. It all in the trans controller. Ron

 

[kb67mopar]

By the way what are you going to do with 3 Hemi's? I am looking for a long block for a good price I can use to start a rebuild project...

 

[Dreamcatcher]

One is (I hope) going in my 68 Charger, one in my 72 Charger and (don't hate me) one is going in a 70 Mustang convertible. I measured it out and don't even have to cut the floor in the stang. I was going to put in a ford 5.0 EFI but it has half the power of the hemi. Besides pissing off my ford and mopar friends I just think it would be cool in a sick sort of way.

 

[Dreamcatcher]

By the way what are you going to do with 3 Hemi's? I am looking for a long block for a good price I can use to start a rebuild project...

Also I am not trying to stereo type here and no criticism or hard feelings but I live by a reservation out here in S.D. and those folks roll them on a daily basis. This 05 I just picked up for 1K and it was a 4 door 1500 4 wheel drive. With a light roll over. So I do see a lot of cars and trucks out here with low mileage that are wrecked. There was a hemi magnum a month ago for 1300.00 with only 70K miles.

 

[Dreamcatcher]

The only real difference I can find is the 45rfe has a finial ratio in 4th gear of 0.75:1 and a 5th gear in the 545rfe is 0.67:1. And suggested rear end ratio is 3:70. In the older car I don't see it being a big deal as it is possible to go too far and actually loose mileage and performance as well. Unless you run a lower gear ratio then it might be better.

 

[kb67mopar]

The only real difference I can find is the 45rfe has a finial ratio in 4th gear of 0.75:1 and a 5th gear in the 545rfe is 0.67:1. And suggested rear end ratio is 3:70. In the older car I don't see it being a big deal as it is possible to go too far and actually loose mileage and performance as well. Unless you run a lower gear ratio then it might be better.

I run an NV3500 5 speed in my Coronet and I think the final on that in 5th is 0.67. I run a 2.94 gear and find myself wanting a 3.23. Though on the freeway the 2.94 is actually about perfect. I would say a 3.70 ish gear would be ok but you might spin a little fast if you do a lot of cruising. My suggestion for a good all around gear would be a 3.55.

if you decide that you don't want to commit the blasphemy of putting the Hemi in the Ford let me know...haha.