4R70W 0r 6R80

[distended]

So then, would you stick with your 4R70W or jump in the fire and do the 6R80 swap?

I was going AOD originally but then after reading things here I decided 4R70W instead. That said, I've read now the 6R80 is a better trans. The 6R80 seems to be the way of the future and I like the idea. I personally don't have a core for either. Since I'm not made of money I think the 4R70W is the less expensive way to go but would like a realistic comparison of the cost of one versus the other. From what I'm pricing, a 6R80, the Atlas and the adapters are going to run somewhere around $8K. Holy Shiitake! That's a lot of money and I haven't included Trans Cooler, Controller and I' sure a buttload more stuff I'm not aware of

I'm going 351W instead of a 302 and will gear axles to make either trans to work. I think I've said it before. I'm not building a show truck. I want reliability and capability on and off road. Not planning on rock crawling, been there, to stressful to me.

Hope this makes sense.

 

[gnpenning]

73azbronco posted this in another thread that I linked at the end. What ratios will work best for your use??



Some more facts on gear ratios between 4r70 6r80 10r80

4r70/AOD (comparing 4r70 to AOD):
Gear Ratio Chart. 4R70W, AOD. First, 2.84:1, 2.40:1. Second, 1.63:1, 1.47:1. Third, 1.00:1, 1.00:1. Fourth, 0.78:1, 0.67:1 ...



6r80:

4.17, 2.34, 1.57, 1.14, 0.87, and 0.69:1.

10r80:


4.70 for first, 2.99 for second, 2.15 for third, 1.80 for fourth, 1.52 for fifth, 1.28 for sixth, 1.00 for seventh, 0.85 for eighth, 0.69 for ninth, and 0.64 for tenth.


Looking at these ratios with our slab sided vehicle, I'd almost say sticking with a 6r80 would be better than the 10 speed for simplicity if nothing else. of course, How is an F150-250 any more aerodynamic or lighter than a bronco? The reason to go for the 6r80 over the 4r70 to me is the first gear almost doubled down to 4.1 vs 2.8.

https://classicbroncos.com/forums/showthread.php?t=281668

 

[Broncobowsher]

As much as I have pushed the 4R70W, given a fresh start in today's world, I would do the 6R80. I have seen them take the power of Ethanol fed supercharged Coyote for years of daily driver and weekend abuse.

As for gearing it, I would probably gear to use 2-6 as my daily driver gears and save 1st for "special needs". Off-road, hole shot, etc.

 

[markw]

What's the latest info on adapter plates for the 6R80?


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[ngsd]

Following:

My NP435 is making noise in my trail rig and considering pulling the Old manual/Klune V out and going Auto/Atlas.

 

[distended]

What's the latest info on adapter plates for the 6R80?


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MarkW

Per Adapters there's this one Performance Adapter


I found another one in a different thread here but I don't have the info with me now. It was somewhere around $1100 but the original poster was happy he didn't have to modify the bell housing.

When I get home I'll post it if no one else gets it first.

 

[distended]

Found it Other Adapter

It's was in this thread, Post #13: Daniel's 1972 build

 

[distended]

So, been spending a lot of time researching pricing to try and answer my own questions. These prices are from these venders. If you can provide a better price on these things, please put it in. If you think what I'm doing is stupid with my picks, please say so. That said, here it is.

Scenario #1
4R60 from Monster Transmission $4311
Atlas II 4:3 $2856
US Shift Controller and Harness $1249
Atlas II to 6R80 Adapter $441
6R80 to SBF Adapter $524
Total $9381

Scenario 2
4R60 from Street Smart Transmission $2520 (Don't know anything about this Co.)
Atlas II 4:3 $2856
US Shift Controller and Harness $1249
Atlas II to 6R80 Adapter $441
6R80 to SBF Adapter $524
Total $7590

Scenario 3
Rebuilt Dana 20 from Toms (Awesome Name!) Off Road $1249
Adapter 4R70W to Dana 20 TC $689
Monster Transmission 4R70W $3438
US Shift Controller and harness $745
Total $6121

 

[Broncobowsher]

I would skip the high dollar rebuild and start with a good used take out.

If you are making big HP, large tires, hard off-road, go Atlas.
Stock/mild engine, fair tires and not beating off-road, keep D20.

 

[nvrstuk]

I can give you a ton of info on my .02 on the differences btw the 4r and the 6r.

Pro's and con's

Cost comparisons

Potential trans problems

Adapters... Watch out!!! Real differences in adapters.

Check out my thread and if you want, I can write up more info on the 6r.


My 4r was the best trans for what I used it for out of the 5 I have had in this same Bronco. I use my Bronco daily, like 16-18 gal/wk. Rock crawl, deep heavy snow, sand and no issues driving it 250 miles in a day with my wife. Just saying, the 4r was the best trans I had... till the 6r, but there's a caveat.

Check out my build thread. Here is the page that starts the 6r. Follow along and you will see issues with the 6r and adapter I used and the only one available at that time post #329

https://classicbroncos.com/forums/showthread.php?t=278607&page=22



I am eager to share what I've learned and researched with you if you're interested. I ran the 4r for 11 yrs with a Baumann (USShift Controller). Trouble free behind close to 500 hp.

I installed the 6 yr 15 months ago. HUGE upgrade. Gear splits are great. Smooth. 1st gear is great. It allowed me to eliminate a doubler because it is so low. I used my doubler for high speed rpm use for snow and sand also so it wasn't just for going slow. Now with 600hp and 710ft lb of torque I don't need the doubler for high speed sand or snow- the engine does it alone.

The 6r is very expensive. Get a used one with good credentials.

Adapters- if you are close to stock hp I think the Perf Auto kit would last BUT, and this is HUGE, the PA kit/design, tech support, fit and finish is all (in a nutshell) crap.

Read the reviews on Summit for the SBF to 6r80 adapter and the reviews for the TC to flexplate adapter- I can verify 5 other Broncos that their kit doesn't work in.

SpeedGems is now making an adapter released within the past year I believe.

I can give you a bunch more info. Let us know what you want to do.

 

[markw]

Great thread. Please keep the info coming. Thanks!


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[distended]

Great thread. Please keep the info coming. Thanks!


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100% agree!

The input is greatly appreciated.

 

[distended]

I would skip the high dollar rebuild and start with a good used take out.

If you are making big HP, large tires, hard off-road, go Atlas.
Stock/mild engine, fair tires and not beating off-road, keep D20.

Engine builder claims the motor is almost 500 HP so good and healthy but not crazy I suppose, only going 33's, maybe 35's but probably not. Won't be hammering on my Bronco, not like I did when I was 17. Just want to dive it and enjoy it, go camping, things like that so what you're saying is perfect.

I need to be reined in sometimes. I've been putting this off for so long just because life happens. Inherited a little over 16K, kids are grown and have a awesome supportive wife who is telling me to build it how I want so I guess it's really her fault.;D

What you're saying makes sense, thank you again.

I can give you a ton of info on my .02 on the differences btw the 4r and the 6r.

Pro's and con's

Cost comparisons

Potential trans problems

Adapters... Watch out!!! Real differences in adapters.

Check out my thread and if you want, I can write up more info on the 6r.


My 4r was the best trans for what I used it for out of the 5 I have had in this same Bronco. I use my Bronco daily, like 16-18 gal/wk. Rock crawl, deep heavy snow, sand and no issues driving it 250 miles in a day with my wife. Just saying, the 4r was the best trans I had... till the 6r, but there's a caveat.

Check out my build thread. Here is the page that starts the 6r. Follow along and you will see issues with the 6r and adapter post #329

https://classicbroncos.com/forums/showthread.php?t=278607&page=22



I am eager to share what I've learned and researched with you if you're interested. I ran the 4r for 11 yrs with a Baumann (USShift Controller). Trouble free behind close to 500 hp.

I installed the 6 yr 15 months ago. HUGE upgrade. Gear splits are great. Smooth. 1st gear is great. It allowed me to eliminate a doubler because it is so low. I used my doubler for high speed rpm use for snow and sand also so it wasn't just for going slow. Now with 600hp and 710ft lb of torque I don't need the doubler for high speed sand or snow- the engine does it alone.

The 6r is very expensive. Get a used one with good credentials.

Adapters- if you are close to stock hp I think the Perf Auto kit would last BUT, and this is HUGE, the PA kit/design, tech support, fit and finish is all (in a nutshell) crap.

Read the reviews on Summit for the SBF to 6r80 adapter and the reviews for the TC to flexplate adapter- I can verify 5 other Broncos that their kit doesn't work in.

I can give you a bunch more info. Let us know what you want to do.

This is awesome! Thanks to you as well.
I did find your build thread and subscribe, been reading just hadn't got to that part yet.

I'll be hitting both you guys up for tips and advice.

 

[Broncobowsher]

500HP, I would still run a stock transmission. They were taking 400+ in mustangs for years. The one I know got beat on was around the 700HP mark for many years and well abused. Got a rebuild after snapping a rear axle at the drag strip on slicks and finally popped a head gasket. While the engine was out and getting more power thrown at it the trans finally was getting a rebuild. But he is aiming for closer to the 1000HP mark after the engine build.

 

[markw]

Best place to buy 6R?


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[markw]

See lots on eBay. Also found Speed Gems adaptors.
Transmissionadapters.com
Anyone know anything about them?


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[nvrstuk]

Stock 6r easily takes 600rwhp for yrs. I put 11 yrs and 500hp to my 4r70 and no trace of sludge in the pan when changing the fluid. which I did often.The 6r's are a tough dependable trans except the leadframe issue so upgrade that when you buy a used junkyard 6r that has less than 70k on it.

I put hundreds/week on so I went with a 30k trans 2 yrs ago. Most guys in their Broncos put 10,000 miles on in 10-15 yrs. I can do that in a good summer of driving.

 

[distended]

Are all 6R's the same bell housing wise or is there a specific version we need that works with an adapter to the SMF?


Do you need to buy the 4X4 version?

 

[markw]

What are you using for a shifter? Hoping OP is wondering the same thingsÂ…Â…


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[distended]

What are you using for a shifter? Hoping OP is wondering the same thingsÂ…Â…


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Hadn't got there yet but yes, good question.

I'd have eventually caught up.