Tranny Question

[Lawhand]

in other words ditch your 20 year old 45RFE tans with soft ware upgrade for a 8 speed. sounds like a plan

 

[jcat]

in other words ditch your 20 year old 45RFE tans with soft ware upgrade for a 8 speed. sounds like a plan

basically. The 45RFE code breaks down like this:

4 - 4 forward gears

5 - torque rating (rating 5 is ~375lb ft, denotes input torque)

R - rear wheel drive

FE - fully electronic control


At least for the old trans. If you look at the 845RE (8hp45) ZF 8spd:

8 - forward gears
45 - refers to 450nM torque capacity, roughly 332 lb/ft input
RE - Means either rwd or 4wd, and electronically controlled


So based upon the torque specs, if you went from a 45RE to an 845RE you would only gain about 40 lb/ft on the front end, which translates to being able to handle roughly another 30-32 lb/ft at the wheels assuming a 20% drivetrain loss...not really worth it. However, by going from a 45RE to an 8hp70, you'd be gaining 140 lb/ft at the front end or being able to handle an additional 110-112 lb/ft at the wheels, which is...shall we say...significant lol

 

[Lhemi]

Monster has a couple sick builds for tran's. Up to 700+ hp.

 

[Z77Z77Z]

A hellcat 8spd crew 4x4 would be the perfect truck for me. I don't got my hopes up.

 

[Lhemi]

Haven't heard any current news about the Hellcat being a option for the 1500. If it is I'll be one of the first in line.

 

[RAMTRPR]

Is it possible to go from a 5-45RFE to a 8HP70?

My truck is an 09' with 195K on her and I have done a lot of work on the motor to keep it going but I am sure the trans is going out soon. I get the surging at Idle that goes away right when I give it gas and i think the torque converter may be slipping.

I would so jump on this if it is possible.

 

[RAMTRPR]

So is it possible to go from 5-45RFE to an 8HP70?


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[savage_46]

So is it possible to go from 5-45RFE to an 8HP70?


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Anything is possible with the right amount of money & knowledge. The truck electrical systems were changed in '13. Doing this tranny swap would require extensive electrical upgrades (splicing harnesses together, getting modules to talk to each other, plus whatever other network communication issues that will most likely arise). Then there's the actual bolting up of the Trans... Cross member, driveshaft(s). Honestly, I don't think it's worth the time, hassle, or money.

 

[Hootbro]

Anything is possible with the right amount of money & knowledge. The truck electrical systems were changed in '13. Doing this tranny swap would require extensive electrical upgrades (splicing harnesses together, getting modules to talk to each other, plus whatever other network communication issues that will most likely arise). Then there's the actual bolting up of the Trans... Cross member, driveshaft(s). Honestly, I don't think it's worth the time, hassle, or money.

What he said! You would probably need a wrecked donor to do the swapping and not value your time to be worthwhile. Otherwise, cheaper sell and buy already built.

 

[CLOUDL1GHT]

If my 65rfe ***** the bed (which I kinda hope it will) I'll be swapping in a 66rfe. True six speed transmission in the same housing as the 65rfe with better gearing.

There's not much info on this swap but I know damn well it will be way easier than trying to swap in the 8 speed

 

[RAMTRPR]

Ok so I will stay with my 545RFE but here is my dilemma. I believe my flex plate is either loose or cracked. So do I pickup s used trans and build it with stall and new flex plate then swap mine out or just take mine in to have it repaired?

Basically I get this loud rattle when in gear and gets louder under power and as rpm increases.

I thought motor but jacked it up and clearly is between motor and trans.


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[RAMTRPR]

Found a 545RFE with about 25k on it for $985 shipped. Do I buy and swap valve body, install shift kit, and 2800 stall, maybe new flex plate. Then have a shop do a quick swap and sell mine to make a little back?


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