4r70w or c4???

[SWFLABRONCO]

The way the part number breaks down on the 4r70w and 4r75w, the 70 or 75 for arguments sake is multiplied by 10 to get their horsepower rating. 70 x 10 is rated at 700 hp and 75 x 10 get the 4r75w rated at 750 hp. Now these probably aren't real world numbers but it's what Ford used. Is it really worth 50hp difference to try and source or pay more for the 4r75w? Like mentioned in another post, it may not even be compatible with the windsors.

 

[Broncobowsher]

4R75 is not compatible with the Windsor engines.

I keep saying that, but no one wants to listen.

 

[ScottC]

The way the part number breaks down on the 4r70w and 4r75w, the 70 or 75 for arguments sake is multiplied by 10 to get their horsepower rating. 70 x 10 is rated at 700 hp and 75 x 10 get the 4r75w rated at 750 hp. Now these probably aren't real world numbers but it's what Ford used. Is it really worth 50hp difference to try and source or pay more for the 4r75w? Like mentioned in another post, it may not even be compatible with the windsors.

I believe this is a simply an old wives tale.

Wiki says the 2003 Expedition 4R70W is good for 506ft-lb.

 

[DanWheeler]

I keep saying that, but no one wants to listen.

my fault - had to go do some reading on modular vs windsor. I'm all schooled up now.

here's a discussion on the meaning of 4R7X

http://www.mercurymarauder.net/forums/archive/index.php/t-33039.html

but i'm not sure it is conclusive. The last post seems to have the final word:




You guys are all close but not quite.

First off the torque rating is in ft-lbs, NOT n-m's.

The 4 is the number of speeds
The 70 or 75 is the amount of torque capacity at the input shaft of the transmission.

The last letter varies.

The original one was a AODE, and E stood for Electronic control.

In the 4R70W, the W was wide ratio.

Then they had a 4R70W+ that started in the 1999 trucks when the 5.4L went in front of it. This trans had a unique treatment to the Forward Sun gear and the one of the set's of pinion gears in the planetary gear set. This is what the original 2003 Marauder had in it.

When the 5.4L 3V F-150 came out in 2004, they upgraded to the 4R75 transmission. They dropped the W rating since they all had that gear set. This trans had upgraded shafts, bearings, etc. They also added a turbine speed sensor (which is really cool technology). The 2004 Marauder got this transmission without the turbine speed sensor. That's why there is a little plug on the side of the case of the 2004 transmissions.

Now, the 2004 F-150 also came with a 4.6L engine. This transmission was called the 4R70E. It didn't get all the upgraded parts that the 75 did, but with the addition of the turbine speed sensor they wanted a way to seperate this from the rest of the 4R7x family, so they dropped the W and went back to an E.....

j

 

[DanWheeler]

and then there's this from wikipedia:

While there is speculation that the 70 can be multiplied by 10 to indicate the ft-lbs of torque this transmission is capable of handling including torque converter multiplication, (i.e. 700 ft-lbs of torque), there is no reliable source indicating this. In fact a Ford document stated that the 2003 "Expedition's 4R70W transmission is rated to handle up to 506 foot-pounds of torque, which provides a large performance cushion beyond the peak torque rating of Expedition's largest available engine." http://media.ford.com/products/pres...cle_id=548&press_subsection_id=423&make_id=92 . It is more plausible that the number indicates the torque handling capability in N-m, as 506 ft-lbs converts to 686 N-m which could be rounded to 700 N-m. The "70" may also refer to the transmission's torque capacity after torque converter multiplication which occurs at low rpm's when the torque converter is more "elastic".


so... who knows?

 

[Broncobowsher]

and then there's this from wikipedia:

While there is speculation that the 70 can be multiplied by 10 to indicate the ft-lbs of torque this transmission is capable of handling including torque converter multiplication, (i.e. 700 ft-lbs of torque), there is no reliable source indicating this. In fact a Ford document stated that the 2003 "Expedition's 4R70W transmission is rated to handle up to 506 foot-pounds of torque, which provides a large performance cushion beyond the peak torque rating of Expedition's largest available engine." http://media.ford.com/products/pres...cle_id=548&press_subsection_id=423&make_id=92 . It is more plausible that the number indicates the torque handling capability in N-m, as 506 ft-lbs converts to 686 N-m which could be rounded to 700 N-m. The "70" may also refer to the transmission's torque capacity after torque converter multiplication which occurs at low rpm's when the torque converter is more "elastic".


so... who knows?

That is very likely true. What I have seen is auto manufacturers use the metric system now and Newton Meter is the common torque rating.
Now consider that is the input shaft torque rating, not the engine output rating. Difference is there is a torque converter between the two. Just to confuse things more, the torque multiplication isn't the same for the entire RPM band. At lower speeds, the converter can multiply more, as the input shaft gains speed the multiplication drops off to nearly the engine's output. So now it is a tuning factor of the engine torque curve and the converter's K-factor. You are now outside the bounds of normal shadetree engineering.

At this point I would start strain gauging the input shaft and doing data aquisition...
No I wouldn't, I would just put the trans in and run it. There are a lot of these running and there isn't a lot of failures. What little I remember are mostly one offs, no real pattern that I have seen.

 

[76 bronco J]

my fault - had to go do some reading on modular vs windsor. I'm all schooled up now.

here's a discussion on the meaning of 4R7X

http://www.mercurymarauder.net/forums/archive/index.php/t-33039.html

but i'm not sure it is conclusive. The last post seems to have the final word:




You guys are all close but not quite.

First off the torque rating is in ft-lbs, NOT n-m's.

The 4 is the number of speeds
The 70 or 75 is the amount of torque capacity at the input shaft of the transmission.

The last letter varies.

The original one was a AODE, and E stood for Electronic control.

In the 4R70W, the W was wide ratio.

Then they had a 4R70W+ that started in the 1999 trucks when the 5.4L went in front of it. This trans had a unique treatment to the Forward Sun gear and the one of the set's of pinion gears in the planetary gear set. This is what the original 2003 Marauder had in it.

When the 5.4L 3V F-150 came out in 2004, they upgraded to the 4R75 transmission. They dropped the W rating since they all had that gear set. This trans had upgraded shafts, bearings, etc. They also added a turbine speed sensor (which is really cool technology). The 2004 Marauder got this transmission without the turbine speed sensor. That's why there is a little plug on the side of the case of the 2004 transmissions.

Now, the 2004 F-150 also came with a 4.6L engine. This transmission was called the 4R70E. It didn't get all the upgraded parts that the 75 did, but with the addition of the turbine speed sensor they wanted a way to seperate this from the rest of the 4R7x family, so they dropped the W and went back to an E.....

j

>>>>> here's another link explaining some internal differences that occured in 2004, although they/he is not as sure sounding on the 70E/75E thing>> http://www.explorerforum.com/forums/showthread.php?t=188119 .............. also...thought I'd mention the 4.2 V6 did come with 4x4 F150's.... back a 4 or 5 years ago when I considered doing the 4R70W swap I found the '99-'03 4.2 4WD transmissions were a very good choice for the bronco... back then, I even found some people selling NewOldStock 4R70W's & they had a few of these 4.2V6-4x4 transmissions for $800 with convertors....I'm still kicking myself for not buying one of them....they were brand spanking new 1999 & 2000 model factory ford units........ below are a couple of links,, first has some good info & the second has a really good internal pics of all the 4R70W parts(see all links within that 4R70W rebuild diary) >>http://www.lincolnsonline.com/tech/00080.html .........http://www.explorerforum.com/forums/showthread.php?t=128800 ............... quote from first link>>•The BEST 4R70W trans that will bolt to a Windsor V8 is a '99 & newer 4.2 V6. It has all the best parts and the same number of clutches as the V8 mod motor transmissions. This trans has: best case, best accumulators, mechanical diode 1 way intermediate clutch, dimpled pan & extended pickup, 450hp capable gear set, best direct clutch drum, best direct clutch plates, best forward clutch wave plate good to 450 hp, best intermediate clutch (4 plate), best stub shaft). Just remember that for a car install, you must switch the manual lever to one from a car.
•ALL prior to '98 do NOT have the expensive mechanical diode 1-way clutch

 

[HGM]

I just replied to the other 4R thread, to the same previous replies...

I have been taught by Ford engineers that it is a nm rating, not lb ft.. 4spd, RWD, 700nm, Wide ratio.. Add a zero and call it nm on all Ford transmissions since the '80s and you'll get an idea of capacity..

The whole mix and match thing is hit or miss in most cases and something I have no experience with. But, if you wanted to, while the case will not fit, I suppose you could stuff the 75 guts into the 70 and ride.. But, I dont think its needed. There are plenty of high HP Mustangs running arround w/o issue, using the later 70's..

 

[DanWheeler]

yeah, the 2 similar threads running is getting confusing at least we're all learning.

so if the 4R70W's upper torque limit is 516 foot lbs then I wonder if its really a good idea to put one behind a 500hp 351?

has anyone here done the J-mod to their 4R70W?
http://www.crownvic.net/tech/4R70Wnotes.pdf

check out all this info on building a bullet proof 4R70W: wow.
http://www.tccoa.com/articles/tranny/transmission/index.shtml

 

[HGM]

so if the 4R70W's upper torque limit is 516 foot lbs then I wonder if its really a good idea to put one behind a 500hp 351?

QUOTE]

Well, Ford didnt do it;D

But, they also didnt build the 500hp 351 to go in front of it. So, my guess would be that its capable of more if modified to do so. In its stock form, I'd feel safe in the assumption that 500ft-lb would work. Its a very good trans.

 

[DanWheeler]

at the bottom of page 6 of this 17 page article on building a tough 4R70W he says he has built 4R70Ws that have stood up without incident to 575 rear wheel HP.

http://www.tccoa.com/articles/tranny/transmission/page6.shtml

I've read the first 6 pages and I'd say this guy knows his stuff.

 

[HGM]

at the bottom of page 6 of this 17 page article on building a tough 4R70W he says he has built 4R70Ws that have stood up without incident to 575 rear wheel HP.

http://www.tccoa.com/articles/tranny/transmission/page6.shtml

I've read the first 6 pages and I'd say this guy knows his stuff.

Looks like good reading... Thanks, now I've got something else to do with my evening..;D