4R70W or 700R4 behind a 408W

[AZ69EB]

Looking for opinions from people who have experience with either the 4R70W or the 700R4 behind a 408W.

I will be swapping my 5.0 EFI out for a stout 408W soon. I’m currently running a ZF 5 speed behind the 5.0 EFI with 4.88 gears and Dana 20.

I’m thinking about swapping out the ZF and going back to OD automatic. I thought it would be more fun with the 408W and a heavy foot.

The big question is 4R70W or 700R4? I already have the ZF adapter that would mate to the 4R70W 4x4 case. Plus, the overall length should be the same. So, no drive shaft changes. I just want to build one OD tranny that will last behind a stout 408W. The 408W will have 450 plus crankshaft hp and torque. Which tranny will be happier behind the 408W? Please advise, so I can save some money over the long term…

Thanks in advance for all your opinions..

 

[pcf_mark]

I have a fair amount of Chevy experience and the 700R4 later models (88 and later) are very stout. Good rebuild parts with a shift kit and it will take 450 HP all day long. You can set it up to run w/o a computer which is a big plus. These are easy to rebuild too - like an over grown C4.

However I have a 4R70W in my truck now and it is very good as well. I am only putting 250 HP through it now planning on going to 400 HP. These need a computer so you will need to assume $500 by the time you get that done. No need for an engine or t-case adapter so I think you come out ahead. Best of all with computer control you can create your own shift curves for light throttle or full throttle. The 700R4 is going to shift harsh all the time so it can take 450 HP when you need it to.

I say 4R70W.

 

[EricLar80]

393w in mine with 4r70w; has no issues when I take some aggression out on it.

Eric

 

[AZ69EB]

Thanks for bith of your replys. I'm leaning towards the 4R70W. But, I would like to hear from more people with higher then stock hp in front of the 4R70W. I know I could build a 700R4 easily to handle the hp. Just not to sure about the 4R70W.

Eric did you do a performance build on your 4R or is it stock rebuild?

Thanks!
Sam

 

[AZ69EB]

That was "Thanks for BOTH of your replies." Autocorrect and IPhone's suck. LOL

 

[Broncobowsher]

With the caveat of "it isn't in front of a 408"
The 4R70W with a mild performance build (as many alto red clutches as I could fit in every pack, shift kit set to half way) survived very nice in front of an 11:1 compression torque built 351W. Several years later I sold it and the fluid was still bright red. Went through a few more owners and the last I knew it was still running just fine.
This was before the 4R75W innards (5.4 mod motor) existed.
There are 4R70W transmissions in sub 10-second mustangs behind blower motors and hooking on drag slicks. They can live.

After owning a computer controlled transmission, the ability to tune shift points without screwing up other shift points. Being able to open up a hysteresis to keep it from shift hunting. Fix a downshift that takes too much throttle to reach and keep it from being too quick to downshift as well. All with clean fingers from a laptop. There is no way I will ever go back to a mechanical controlled automatic transmission.

 

[AZ69EB]

Bowsher,

Regarding torque converter, is there any difference decided on the stall speed of a lock up torque converter vs a non-lock up torque converter? I never had this option in the past.

Also, how many extra red clutches and steels were you able to add?

Just curious and thanks!

 

[Broncobowsher]

It was over 10 years ago (I guess that means it held up). I don't remember how many. Just some would have an option for 5 or 6, so I did the 6 in that case. The hardest one was finding the reverse clutch that added an extra friction. I had to explain that being 4WD I was likely to put a lot more power through reverse then a typical street car. At which point the parts were found.

I did everything through Baumann back before they renamed USshift. The only thing I would have done different (and being lazy and not wanting to get back into the wet stuff) would be to dial back the 1-2 shift firmness from the 3rd setting to the 2nd. But a lot of that was due to the 4.88 gears. It was on my plan to dial it back the next time I serviced the transmission. It never needed servicing and I sold the truck instead.

As for the stall speed, the lockup bypasses that so you can be a lot more forgiving. That should be matched to the cam, but beware of the drag race mentality of most convertor sales and stay on the lower side for drivability. A race convertor that stalls at 3400 is a great match for a bigger cam when racing. But when you have no driving force through the convertor until 2000 RPM it isn't very street friendly. I was using the stock Explorer convertor and was happy with it. The cam had a good idle and bottom end and was well matched. But load it up and it would stall out about 2400 RPM. But at idle it had enough creep force that it drove like a normal automatic. None of this rev it up to get any driving force that can be a problem with higher stall convertors. There is a ton of engineering in a convertor besides the stall speed.

 

[AZ69EB]

I made a decision and purchased an 4R70W off CL tonight. I tried to post a picture from IPhone, but no luck.

Thanks for the replies and helping me with making this decision.

 

[walls]

What transfer case are you guys using behind the 4r70w.

 

[AZ69EB]

I'm going to run the Dana 20. I already have the ZF5 adapter to mate the two.

 

[walls]

Is there any year the 4r70w transmissions were better than others or are they all the same. Also who offers the adapter for the dana 20? I am about to pull the trigger on the same set up. Any more info before I do would be appreciated. Thanks walter

 

[Broncobowsher]

Is there any year the 4r70w transmissions were better than others or are they all the same. Also who offers the adapter for the dana 20? I am about to pull the trigger on the same set up. Any more info before I do would be appreciated. Thanks walter

Generally, the newer the better, more upgrades in the trans. The '98 and up are the normal good ones with the upgraded 2nd gear mechanical diode.

Two case versions, Windsor and mod motor. Windsor has a 2-bolt starter pocket, mod motor has 3 bolt starter pocket. Unless running a mod motor you want the 2-bolt. That was also found on 3.8 and 4.2 V6 applications but the V6 has the wrong balance in the flexplate.

Can be had in 2WD and 4WD versions with the 4WD being the standard big 6-bolt pattern with a 31 spline shaft. Advance adaptors has several options for mating to a D20. Or junkyard options exist (NP205) or an Atlas can be ordered that will bolt right on a 4WD version.

 

[AZ69EB]

I found a 97 5.0 AWD explorer that was being parted on CL. He still has the complete 5.0 with GT40P heads with complete front dress in Phx CL. I paid $125 for trans. I even helped split the T case from it. I'll up grade as needed.

 

[EricLar80]

Thanks for bith of your replys. I'm leaning towards the 4R70W. But, I would like to hear from more people with higher then stock hp in front of the 4R70W. I know I could build a 700R4 easily to handle the hp. Just not to sure about the 4R70W.

Eric did you do a performance build on your 4R or is it stock rebuild?

Thanks!
Sam

Didn't even rebuild it. Took it apart to install the new output shaft and slapped it back together.

Eric