66rfe to 8hp70 swap

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Oldno7jd

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Hello all! I have a 2018 power wagon and having transmission issues. I've been looking into new and rebuild options. But, I've recently been reading about swapping an 8hp70 in. Wondering if anyone here has done this? What it entails? Any guidance at all? This looks like what I would like to do. I live the truck, hate the tranny.
 

olyelr

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Man, same here…love everything about my truck…except the tranny.

Unfortunately i would have to guess it would be a nightmare of a swap, from all of the electronics and computers and the twist knob shifting…but man if its somewhat doable i would pay to have my working tranny removed and replaced with one lol
 

Grand Mesa

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Getting my 66rfe rebuilt. Called the shop immediately to schedule the earliest appointment. That was over a month ago. If I requested a 8HP70 instead it wouldn't ever get repaired even if it was doable.
 
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Hello all! I have a 2018 power wagon and having transmission issues. I've been looking into new and rebuild options. But, I've recently been reading about swapping an 8hp70 in. Wondering if anyone here has done this? What it entails? Any guidance at all? This looks like what I would like to do. I live the truck, hate the tranny.
2017 PW Here, and not currently having issues but it is always floating in the back of my mind. After researching it my conclusion is that it would be cheaper and less hassle to sell your 66RFE wagon and buy a new one with the ZF 8speed. Not what you want to hear, I know.
 

Grand Mesa

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Grand Mesa

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@Grand Mesa are your getting an OEM 66RFE rebuild, or they're improving upon the original design with aftermarket parts like Sonnax?
HaraldHardrada,

They're improving on the original design with the Sonnax Smart-Tech Overdrive Clutch Housing Kit, Valve Body Component;Sonnax Accumulator Piston Kit, etc., plus cleaning of the cooler. Over $4.5K of parts. 100,*** miles

The underdrive return spring had broken, the cooling bypass valve was toast, and the overdrive clutches were burnt. Still going with the OEM cooling bypass valve due to our cold winter weather where driving in subzero Fahrenheit temperatures is a common occurrence.
 
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HaraldHardrada,

They're improving on the original design with the Sonnax Smart-Tech Overdrive Clutch Housing Kit, Valve Body Component;Sonnax Accumulator Piston Kit, etc., plus cleaning of the cooler. Over $4.5K of parts. 100,*** miles

The underdrive return spring had broken, the cooling bypass valve was toast, and the overdrive clutches were burnt. Still going with the OEM cooling bypass valve due to our cold winter weather where driving in subzero Fahrenheit temperatures is normal.
Appreciate the data points! Sounds like you will end up with a robust unit, not cheap, but quality costs. I'm also at 100K on the odometer, no issues yet but if I keep it long term rather than trying to trade-up to a 2019+ I'll probably be doing many of the same Sonnax upgrades. Cost aside, my real worry is having the damn trans go out on me deep in a National Forest.
 
OP
OP
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Oldno7jd

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Getting my 66rfe rebuilt. Called the shop immediately to schedule the earliest appointment. That was over a month ago. If I requested a 8HP70 instead it wouldn't ever get repaired even if it was doable.
Right! I have an appointment on the 17th, that will be 5 weeks after scheduling. This is all things I've been looking at in between.
 

jambbii

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Figured I would just throw my 2 cents in here. I just finished a 5.13 gear swap a few months ago in my 18. I can honestly say this is how it should have come and the 66rfe works freaking great. The biggest surprise was the engine braking and how well it worked towing now.

Make sure you put some sort of stiffened channel plate in to prevent cross channel leaks. Take advantage of all the R&D done by the diesel world because most of that stuff works in these transmissions.
 

jawzs2

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Hello all! I have a 2018 power wagon and having transmission issues. I've been looking into new and rebuild options. But, I've recently been reading about swapping an 8hp70 in. Wondering if anyone here has done this? What it entails? Any guidance at all? This looks like what I would like to do. I live the truck, hate the tranny.

Some good info here

 

olyelr

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Figured I would just throw my 2 cents in here. I just finished a 5.13 gear swap a few months ago in my 18. I can honestly say this is how it should have come and the 66rfe works freaking great. The biggest surprise was the engine braking and how well it worked towing now.

Make sure you put some sort of stiffened channel plate in to prevent cross channel leaks. Take advantage of all the R&D done by the diesel world because most of that stuff works in these transmissions.
Great to hear!

Ive always guessed a set of 5.13s would help greatly, but its just such a costly upgrade lol
 
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Figured I would just throw my 2 cents in here. I just finished a 5.13 gear swap a few months ago in my 18. I can honestly say this is how it should have come and the 66rfe works freaking great. The biggest surprise was the engine braking and how well it worked towing now.

Make sure you put some sort of stiffened channel plate in to prevent cross channel leaks. Take advantage of all the R&D done by the diesel world because most of that stuff works in these transmissions.
Which Valve Body / plate did you go with?
 

jambbii

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I'm still gathering parts but I have the d & j one. Going to use sonnax for the rest of vb parts.
 
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