Is there a max HP rating on 4R75W, torque vs HP?

[fadetoblack]

I thought that what really mattered was the torque coming into the input shaft of the trans. The 4R75W is rated at 750 ft/lbs, correct? Does the HP generated even come into play when trying to figure if this trans will take the additional power generated by engine mods? Seems like 750 ft/lbs would cover just about any power mod you could do to the engine. What am I missing here?

[Billy]

I have yet to see anybody actually prove that the "70" or "75" stands for 700/750 ft/lbs of tq.
The highest number I've seen in ford documentation is 506 ft/lbs for the 4r70w.
I personally wouldn't push a stock AODE transmission past 500hp or 500ft/lb. It's a lot of stress on the internals.

[ntd]

The 4r75 name does designate it torque capacity, 4 speed, rear wheel drive & 750 ft/lbs of torque capacity. You also have to keep in mind the torque convertor multiples the engine torque by 2. SO an engine making 500ft/lbs of tq after the convertor is in the realm of 1000ft/lbs tq at the input shaft. There is one big weakness to this trans the WOT shift from 3-4 will kill a 4r70/75 trans in a short time at stock power levels. keep the RWTQ @ 450 add a good trans cooler and drive intelligently it should hold fine IMO but what do I know:)

[mcgyver59]

Anything over 500rwhp with the j mod and you are on borrowed time, especially with a PD blower.

[LANDY]

I'm putting 520rwhp plus a 125shot on a stock j-modded trans and a *****y TC. Let's see how long it last.

[ntd]

Anything over 500rwhp with the j mod and you are on borrowed time, especially with a PD blower.

It's not the HP that kills transmissions or other driveline items it's TQ. Torque is defined as tendency of a force to rotate an object about an axis, IE snapping hard parts or over powering clutches. There is a reason nitrous always brakes stuff TQ;).


I'm putting 520rwhp plus a 125shot on a stock j-modded trans and a *****y TC. Let's see how long it last. ok so 520 RWHP nice :) what is RWTQ?

[LANDY]

The RWTQ off the Nitrous is 464

[ntd]

The RWTQ off the Nitrous is 464

so figure 928 FT/LBS of TQ at the the input shaft of a j-modded trans. J-mod will help with the apply time and pressure at the shifts this is were most of the damage is done causing the clutches to glaze over. If the trans was in good shape before it will hold well for a reasonable amount of time, obviously it's life is shortened and will require an over haul at some time. Keep the fluid clean and temps low but that nitrous may very well be the nail in the coffin though:beer:

[Spectragod]

what is RWTQ?

In my case, 526, but I had the trans built.

[ntd]

In my case, 526, but I had the trans built.

The 4r70/75 is one of my favorite transmissions to rebuild it's 1st, 2nd and 3rd gear does really well if you cram a few more steels and frictions in. This can be achieved using a slimmer clutch stack or removing the pressure plates and using a steel in its place. Who built your trans and how many miles?

[MarauderJim]

My Marauder dyno'd at 433 at the rear wheels. I'm told that equates to 578 HP at the flywheel. Raced the car in September and I had frequent shifting problems. I have the original transmission with a Precision 3500 stall torque converter. I plan to record my next runs with the SCT tuner... but I think the verdict would be that I need a better tranny! :bigcry:

[ntd]

My Marauder dyno'd at 433 at the rear wheels. I'm told that equates to 578 HP at the flywheel. Raced the car in September and I had frequent shifting problems. I have the original transmission with a Precision 3500 stall torque converter. I plan to record my next runs with the SCT tuner... but I think the verdict would be that I need a better tranny! :bigcry:

Jmod or not? how many miles? I don't know if SCT has the capability to monitor trans rat and gear rat but those two pids will help determine if the trans is slipping or not.

[sailsmen]

I'm putting 520rwhp plus a 125shot on a stock j-modded trans and a *****y TC. Let's see how long it last.

Thanks for the info.

I have 52 1/4 runs and 47K miles. I would not be surprised if I went another 47K miles driving it easy, however I will be surprised if I get more than 4-6 1/4 runs.

[LANDY]

Thanks for the info.

I have 52 1/4 runs and 47K miles. I would not be surprised if I went another 47K miles driving it easy, however I will be surprised if I get more than 4-6 1/4 runs.
I put the info in my sshs11 thread also.
BTW at the shootout I did nine 11.7 at around 116-117mph and two passes on the juice.
Got home and lined up against someone who called me out in a gutted ls6 chevelle and still took his money.
My problem now is that I'm out of gear as soon as i hit the traps. I say 3.73s are in my future.

[sailsmen]

I put the info in my sshs11 thread also.
BTW at the shootout I did nine 11.7 at around 116-117mph and two passes on the juice.
Got home and lined up against someone who called me out in a gutted ls6 chevelle and still took his money.
My problem now is that I'm out of gear as soon as i hit the traps. I say 3.73s are in my future.

Look at the TimeSlips and your MPH. Looks like you had some spin when the Nitrous came on in second.

[LANDY]

Look at the TimeSlips and your MPH.
Your a funny guy.
I'm trapping at 6600rpms on 29" tall tires. Once I get a decent TC it will be even higher.

[MarauderJim]

What's a Jmod? I have 36K on the car. Only raced on 3 days...15-20 races per day.
I have Trilogy SC, Stainless works headers & full exhaust system. Richmond 4-10s and a larger throttle body and mass air meter. 3500 torque converter and KNN air intake. I have billet alum control arms & Watts link. Six piston Willwood brakes all around with widened factory wheels & Nitto drag radials.

[LANDY]

A j-mod consist on a modification to the trans valvebody. It helps the fluid flow on the tranny by drilling bigger holes on certain places of the plate. Google it and you will learn more about it.

[Billy]

The 4r75 name does designate it torque capacity, 4 speed, rear wheel drive & 750 ft/lbs of torque capacity.
Do you have a source for this? Everything I've read leads me to believe that's just a myth. I think it's more likely that the original meaning of the "70" is to indicate that the OD band has a ratio of .70:1

[Spectragod]

The 4r70/75 is one of my favorite transmissions to rebuild it's 1st, 2nd and 3rd gear does really well if you cram a few more steels and frictions in. This can be achieved using a slimmer clutch stack or removing the pressure plates and using a steel in its place. Who built your trans and how many miles?

Darin @ BC did the trans work, car had 19k on it when it got overhauled. Also changed the convertor to a CircleD and added an external cooler.

[LJ on 24's]

I put the info in my sshs11 thread also.
BTW at the shootout I did nine 11.7 at around 116-117mph and two passes on the juice.
Got home and lined up against someone who called me out in a gutted ls6 chevelle and still took his money.
My problem now is that I'm out of gear as soon as i hit the traps. I say 3.73s are in my future.

Why not use motive 390 gear

[sailsmen]

Good Luck with the 3.73. Wonder how many MM with a lower ET are using 3.73?

[LANDY]

Just stay tuned, this is a street car not a track car.

[LANDY]

Why not use motive 390 gear I have heard they are not as quiet as the Ford racing ones. But I might try them

[gdmjoe]

Meaning of "nn" portion of the 4RnnW designation .....


4R70WA revised version of the AODE was released in 1993 with the Lincoln Mark VIII. 4R70W stands for 4 gears, Rearwheeldrive, 70 stands for the 4th gear ratio, and Wide gear ratio. It has lower 1st and 2nd gear ratios for better take-off acceleration and improved gearset strength. On vehicles powered by a 5.4 L V8, a stronger gearset is used than in normal duty 4R70Ws. In 1998, due to durability concerns, the intermediate one-way roller clutch was replaced with a mechanical diode providing extra holding capacity and longer service.

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/presskit_display.cfm?vehicle_i d=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".

The gear ratios are: 1st: 2.84 :1 2nd: 1.55 :1 3rd: 1.00 :1 4th: 0.70 :1 Rev: 2.23 :1
Reference: Wikipedia - Ford AOD transmission (http://en.wikipedia.org/wiki/Ford_AOD_transmission) ««« -click-
.

[ntd]

Anyone can make or edit information on Wikipedia so I rule them out and go straight to the source but there is no documentation from Ford(that I have ever seem) as to if the 4r70 is named after it's 4th gear ratio or torque capacity. I purpose this question if in fact the 4r70 is named after it's ratio then why is a 4r70 with increased torque capacity called a 4r75;). Looking at the current crop of ford trans 4f50n, 4f27e, 4r100, 5r55, 5r110, 6r80, 6f50/55 & 6f35 there isn't much consistency in trans missions being named for there final gear ratios. Torque capacity seems like a much more plausible answer

[Blown3.8]

Your a funny guy.
I'm trapping at 6600rpms on 29" tall tires. Once I get a decent TC it will be even higher.

What gear do you have in there now?

We trap 6300 at 128mph with 4.10's and 28" tall tire.

[LANDY]

What gear do you have in there now?

We trap 6300 at 128mph with 4.10's and 28" tall tire.
I have 4.10s. I might be staying on the throttle a little longer but I know right before I let off it was at 6600.

[Billy]

Anyone can make or edit information on Wikipedia so I rule them out and go straight to the source but there is no documentation from Ford(that I have ever seem) as to if the 4r70 is named after it's 4th gear ratio or torque capacity. I purpose this question if in fact the 4r70 is named after it's ratio then why is a 4r70 with increased torque capacity called a 4r75;). Looking at the current crop of ford trans 4f50n, 4f27e, 4r100, 5r55, 5r110, 6r80, 6f50/55 & 6f35 there isn't much consistency in trans missions being named for there final gear ratios. Torque capacity seems like a much more plausible answer
The numberings for some are random, other have meaning. They probably just upgraded to "75" because it sounds cooler than "70"
You guys realize that the idea of the 4r70w being able to handle 700 ft/lbs of torque is absolutely ridiculous, right? Come on.

[ntd]

The numberings for some are random, other have meaning. They probably just upgraded to "75" because it sounds cooler than "70"
You guys realize that the idea of the 4r70w being able to handle 700 ft/lbs of torque is absolutely ridiculous, right? Come on.

Yea that's it randomization or maybe they have dart board with names on it next to the jumping to conclusions mat(note- this is sarcasm & no way shape or form pot stirring, got in trouble for this last time with the Pitbull thread:))

ridiculous how so? most Eaton swap cars can get @ 400rwtq add torque converter multiplication (about 2x) that's 800 ft/lbs to the input shaft on a stock car with a blower. Most MM seem to do just fine at that power level for some time.

[fadetoblack]

So the bottom line is...if I add the Trilogy S/C, the trans will "probably" be OK. I should probably be more nervous about a snapped stock axle shaft???

[SC Cheesehead]

So the bottom line is...if I add the Trilogy S/C, the trans will "probably" be OK. I should probably be more nervous about a snapped stock axle shaft???

If you run street tires, doubtful the axles are gonna snap, tires will spin before you generate enough TRQ to snap an axle.

Also, you gonna be running the basic Trilogy package? HP and TRQ levels will not cause you any trans or axle grief, unless you do forced downshifts from OD to 2nd under WOT. (Always turn off the OD before you nail the loud pedal).

[Billy]

Yea that's it randomization or maybe they have dart board with names on it next to the jumping to conclusions mat(note- this is sarcasm & no way shape or form pot stirring, got in trouble for this last time with the Pitbull thread:))

ridiculous how so? most Eaton swap cars can get @ 400rwtq add torque converter multiplication (about 2x) that's 800 ft/lbs to the input shaft on a stock car with a blower. Most MM seem to do just fine at that power level for some time.
I respect your opinion and I do understand what you're saying, but can you find an actual reliable source that backs this up?
I don't think you could.
750 is a big number. That's the kind of numbers that people build bullet proof performance transmissions to withhold. I just don't think that ford would put a performance transmission in normal passenger cars.
Most of my knowledge is with the 4r70w, which is a bit downgraded from the 4r75w I know, but all AODE transmissions are pretty similar.

I apologize if I'm incorrect or out of line here, but I really don't want people blowing up their transmissions because they assume it can handle a lot more power than it really can.

[Serge]

As far as I know there is nothing that would indicate that 70 stands for 700 ft-lbs. Not even n-m.

No one from Ford has ever confirmed what it stood for so this is all based on speculation and assumptions.

[ntd]

correct there is no holy grail from ford to settle this debate. Wiki is about the best information you will find as unlike a manual transmission with very cut and defined ratings. It's hard to find meaningful torque specification for automatic transmission it's sort of like trying to nail jelly to a wall.

Fact of the matter 5.4 3v makes 365 fb/lbs multiply that by 2 that is 730 ft/lbs to the input shaft. 730 tq is a big number and it's a factory setup so buy your definition the 4r75 is a factory built, "bullet proof performance transmissions". Seems to fall right in line with the name 4r75 meaning 4 speed, rear wheel drive, 750ft/lbs TQ rating.

on a side note all the auto trans training I've had from Ford the last 2 number I've been told are related to torque capacity but still there is no hard facts in writing agree to disagree?

[Spectragod]

The numberings for some are random, other have meaning. They probably just upgraded to "75" because it sounds cooler than "70"
You guys realize that the idea of the 4r70w being able to handle 700 ft/lbs of torque is absolutely ridiculous, right? Come on.


No clue if it can handle it, I do know this, Darrin @ BC backed mine with a 2 year warranty, behind a blower, clearly he believes it can handle it.:flamer:

[Billy]

No clue if it can handle it, I do know this, Darrin @ BC backed mine with a 2 year warranty, behind a blower, clearly he believes it can handle it.:flamer:

Uhh that's because Darrin builds performance transmissions. The original poster was talking about the stock transmission :shake:

[guspech750]

Uhh that's because Darrin builds performance transmissions. The original poster was talking about the stock transmission :shake:

I don't think many places waranty performance work and parts too often. Especially a transmission!!
two year waranty on a trans is pretty sweet built or not.


---
- Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[Spectragod]

I don't think many places waranty performance work and parts too often. Especially a transmission!!
two year waranty on a trans is pretty sweet built or not.


---
- Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

That was my point, quality vendor, 2 years and -0- problems, spend the $$$ and don't look back.

[Spectragod]

Uhh that's because Darrin builds performance transmissions. The original poster was talking about the stock transmission :shake:


Uhhmmmm, go big or go home?

Mod motor = $$$$, all the related parts = $$$$, there is no such thing as cheap and reliable, it will only be one way or the other, and if you want it to last, it will be $$$$.

[guspech750]

That was my point, quality vendor, 2 years and -0- problems, spend the $$$ and don't look back.

Your point was spot on.

I too would like to have my trans rebuilt just to make sure it lasts and takes my abuse.

No issues yet on stock trans. But........................... .........................

---
- Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

[Billy]

Uhhmmmm, go big or go home?

Mod motor = $$$$, all the related parts = $$$$, there is no such thing as cheap and reliable, it will only be one way or the other, and if you want it to last, it will be $$$$.

I know. You and I agree 100% on this.

[IwantmyMMnow!]

Paging Mr. Babcock....Mr. Steve Babcock....

Maybe he can shed some light on this 'burning' question?

[sailsmen]

11-09-2011, 09:09 AM
Blown3.8
I make *BLING* happen


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Quote:
Originally Posted by LANDY
Your a funny guy.
I'm trapping at 6600rpms on 29" tall tires. Once I get a decent TC it will be even higher.

What gear do you have in there now?

We trap 6300 at 128mph with 4.10's and 28" tall tire.
__________________
~Chris



I have 4.10s. I might be staying on the throttle a little longer but I know right before I let off it was at 6600.

Landy, you want to take a look at your trans for slippage.

The "funny guy":lol:

[LANDY]

Lol the only look is gonna take is when it gets built. Plus the dattalogs don't show it.

[sailsmen]

The Laws of Physics do not apply to Landy?

[Paul T. Casey]

Uhhmmmm, go big or go home?

Mod motor = $$$$, all the related parts = $$$$, there is no such thing as cheap and reliable, it will only be one way or the other, and if you want it to last, it will be $$$$.

Actually, the quote is Fast, Reliable, and Cheap. You can have any two.

[FordNut]

I destroyed numerous 4r70w trannys, and even tore up the 4r70w which had been built with the "better" 4r75w parts. I run a 4r100 and that's bulletproof!

[Billy]

Yeah I had a friend who had 2 "upgraded" 4r70ws fall apart on him, both built by a site sponsor here.

[Spectragod]

Yeah I had a friend who had 2 "upgraded" 4r70ws fall apart on him, both built by a site sponsor here.

I expect no performance part to last forever, given the way that they are used. If you wanna play, you gotta pay.

Horsepower is not a cheap hobby, neither are the parts, *****s gonna break, while it stings the wallet, it's just the way it is....

[Serge]

Yeah I had a friend who had 2 "upgraded" 4r70ws fall apart on him, both built by a site sponsor here.

Another reason why I am building my own.

[ntd]

Another reason why I am building my own.

Seeings as there tread is so far off the rials from what the op asked:P any details on your built transmissions?