[JoeShuck]

This may be a dumb question...but yet I ask anyways. I am in the process of having a 427w stroker built and am having some issues deciding what to do with the tranny rear-end. I have a very very strong rear and differential so that doesn't need to be touched, however I have 4.10 gears. I did get my stock C4 built with racing clutches etc. a while back; however I now can't go over 80mph comfortably with the RPMs. My question is whether I should just change the rear gears, or should I get a performance AOD transmission? The way I figure is that I am going to have to build my tranny stronger no matter what since the engine I am building is going to be pushing 600hp(hopefully close to it). So the cost I am looking at is either rebuild the tranny+new rear gears, or AOD and keep the 4.10s. I am leaning more toward the AOD, but I don't know if I will still have issues with the rear gears being so small. Any ideas??

Here is the AOD I was considering http://www.ford-aod.com/ (stage 4)

Also open to tranny suggestions!!

 

[Cougrrcj]

With the wide ratio gearing that is used in the 'stage 4' AOD transmission, you really don't need your 4.10 gears. I had a buddy build me a wide-ratio AOD to put behind my 475hp 393W (demonstrated 380hp to the ground based on my weight, ET and MPH). The wide-ratio gearing makes my 3.55 rear gears feel like 4.19s off the line, yet I'm only turning 1850rpm at 60mph in overdrive. Best of both worlds!!

I have been using a ACC 'Boss Hog' Nightstalker lockup converter pt#26401 w/2700rpm stall. This year I'm looking for a bit more performance off the starting line, so I'm sending my converter back to ACC and they'll re-stall it to ~3200rpm for $85+shipping (basically turning it into a 'Street Bandit' pt#26402). I'm also switching to a Silverfox SPT-R valve body with 'stage 3' calibration so I'll have a normal shift pattern and an o/d lockout button. Otherwise you end up doing a '2-D-2 shuffle' to manually shift from 1st to 2nd, then back to D for third... My trans currently is not capable of WOT in o/d, but will be with the new valvebody... Silverfox also markets complete transmissions spec'd the way you want it.

 

[Bad69cat]

Similar here but I have 2800 Stall on 3:55 rears. I do have to to the D-2-D shuffle and I'm not crazy about it but it works and I love the highways manners and hearing myself think (not that I really do....just sayin) At the time I built mine the only other options were very expensive -- Lentech or Bauman. Now there are many options and I think that Silver Fox set up is worth a look as well as Art Carr - He has a VB that pretty much doesn't depend on the TV lever for pressure if you want to go the AOD route anyway. Fairly easy to set up and run from what I hear. The AODE route is attractive but still a bit more spendy. As for the rears 4:10's are still gonna be a bit unruly if you plan to street it 80% of the time. If you track it a bunch....mmmeh maybe keep 'em? If your looking at high horsies - I'd lean towards the tried and true Lentech or Bauman. The nice thing about Bauman is the electronic adjustability they bring to the table....though they recently changed hands I think (or names?)?

I'm not sure I have the same launch velocity as I did with my FMX though...? It feels a bit sluggish yet...but the top end holy cow did it make a difference! It's pulling harder than it ever did - I'm currious as to waht my 60' will look like? Haven't had it out since the AOD went in - lost job - yada, yada...

I bought my Red Eagle clutch kit and gut parts from Phoenix Transmissions and had a local guru build mine. Pretty much the trans your looking at. I got the trans out of a 89 truck. The only issue I ran into and nobody ever seems to mention is that the shift lever needs to be turned over if it was a column shift vehicle! BEFORE - you install it into the vehicle. Also you will likely need to lose 1" off the driveshaft and find a new trans x-member. I ended up building all my own cross members an linkages to accomodate mine, (except the Lokar TV cable).

 

[Cougrrcj]

Baumann is now operating as becontrols.com

Every Ford trans website I looked at recommended either the SilverFox or LenTech valvebody for the AOD. I went with Silverfox only because they're in the US (Lentech is in Canada). With duties and customs hassles...

I didn't have any problems with my Baumann shift kit in my trans - it shifted fine and hard enough to bark the drag radials at both the 1-2 and 2-3 shifts. I just wanted to have a normal shift pattern for when I go racing.

 

[Rosfrei]

With the wide ratio gearing that is used in the 'stage 4' AOD transmission, you really don't need your 4.10 gears. I had a buddy build me a wide-ratio AOD to put behind my 475hp 393W (demonstrated 380hp to the ground based on my weight, ET and MPH). The wide-ratio gearing makes my 3.55 rear gears feel like 4.19s off the line, yet I'm only turning 1850rpm at 60mph in overdrive. Best of both worlds!!

Am I safe to assume the WR gearing pretty much puts 1st, 2nd, and 3rd gear at a lower gearing? Yet retains the ultra low OD?

 

[Cougrrcj]

Stock AOD gearing is 2.40, 1.47, 1.00, .67
Wide ratio (4R70W) is 2.84, 1.55, 1.00, .70

 

[JoeShuck]

Okay, using those numbers you have provided, I know there is a way to calculate MPH and RPMs given tire height and rear gear ratio. I have already told the shop to order a AOD with "Hot Rod Guts," as they say it, and I am wondering if I should go with the 4R70W or standard. Maybe this is more of a "What would you do?"

 

[Cougrrcj]

The wide ratio gearing gives you a lower First gear off the line, yet the cruising (highway speed) is largely the same., Or to put it another way, you can run a more conservative gear, yet still have a big punch off the line. Like I said before, the wide ratio gearing makes my 3.55s feel like 4.19s (the 18% gearing difference) off the line, yet they act like (because they are) 3.55s in Third gear. The .03 difference between the ratio sets in OD is inconsequential...

OK, so if you go to this website to compare various tire sizes and most importantly, how many revolutions they make in one mile. Multiply that by your rear gear ratio to see how many revolutions your engine had to turn to travel that one mile. OK, so that result is how may RPMs your engine is turning at 60mph if you have a 1:1 ratio in the trans, or you can multiply that engine RPM by the overdrive ratio. That tells you how many RPMs the engine is turning at 60mph in o/d.

Hypothetical tire makes 740 revs per mile x 3.55 rear gears = 2627engine RPM at 60mph in Drive.
2627 engine RPM x .7 overdrive ratio = 1839 engine RPM at 60mph in overdrive.

Another way you can look at it is to compare rear gear ratios and low gear ratio in the trans. Say for example I have 3.55 gears. multiply that by the 2.84 First gear of the 4R70W transmission, then divide it by the first gear ratio (2.40) of the AOD. This will tell us what rear axle ratio you'd need to have the same effective gearing.

3.55 x 2.84 = 10.082 effective First gear ratio

10.082 / 2.40 = 4.20 So you'd need a 4.20 axle ratio to have the same effective First gear as I do with my 3.55s and the wide ratio transmission.

If we substitute the C-4 or C-6, they have a First gear ratio of 2.46, so 10.082 / 2.46 = 4.098, so you'd need a 4.10 gear to have the same First gear ratio as my 3.55s with the wide-ratio 2.84 First gear.

Now, if you factor in JoeShuck's 4.10 axle ratio now..., with wide-ratio trans gearing, that makes those same 4.10s feel like:
4.10 x 2.84 = 11.644 meaning his engine is turning 11.64 revolutions to make one revolution of his rear tires.

11.644 / 2.40 = 4.85. With the 4R70W, he'd have the same effective rear axle gearing of 4.85s and a conventional AOD

 

[JoeShuck]

So, that means I am going to be smoking tires all the way through 3rd with the wide ratio... Aside from that, lets say you were handed a cougar with 4.10s in the rear and the option of the stock AOD or the wide ratio; which would you pick? Would you pick either of the two and keep the 4.10s? Or would you pick the wide and lower the ratio in the rear? I guess I'm wondering what the drivability will be like from stop to 60...too uncomfortable and too fast in the shifting or...?

 

[Cougrrcj]

Joe, that'd depend on what I want out of the car... Where is the powerband of the 427W you're building? This gearing and converter stall should have been addressed before you spring for a cam!

 

[Cougrrcj]

Personally, I like the wide ratio gearing - especially with the torque you'll have from the 427 stroker to overcome the bigger RPM drop at shift points. So I like the wide ratio trans, and a more moderate rear axle ratio.

 

[Art]

I am leaning more toward the AOD!

Sounds like a good plan.

 

[JoeShuck]

I have not ordered a cam yet because of this. I am probably going to stick with an 11" 2500-2600 converter to get the shifting smoother and more driveable as well as keep the heat down. The 4R70W is an electronic transmission, correct? What does this entail as far as parts and installation?

 

[Cougrrcj]

Yes, 4R70W is electronic, but that trans you were looking at in your original post has the 4R70W wide-ratio gearset in an AOD case - giving you a hybrid mechanically-controlled wide-ratio AOD, like the trans I'm running...

 

[JoeShuck]

Huh...okay. Well I have been looking at control boxes and TPS units for the 4R70W and they are frickin sweet. The control box is unreal and offers full control over many different features/functions. Would this just be a big pain or pretty neat technology and features? Mostly a preference?

 

[AZCAT]

Joe,

Have you read my thread?
http://www.mercurycougar.net/forums/showthread.php?50657-4R70W-AOD-Swap-Details

 

[Cougrrcj]

The advantages of running a true 4R70W (with a stand alone controller) are:

1. That it can handle 700lb/ft of torque because it uses a one-piece input shaft. AODs use an outer and inner shaft. The stock inner shaft is limited to 450 lb/ft torque, although hardened aftermarket inner shafts can handle 550 lb/ft torque.

2. Torque converter lockup is electric and independent of gear selection. AODs by design are locked up in D and o/d.

3. Normal shift pattern. AODs are 2-D-OD. To get an AOD to manually shift 1-2-3 you have to do the '2-D-2 shuffle' which is hard on the trans internals... unless you spend $$$ to get an aftermarket electronic o/d lockout valvebody....

4. Programmable 'automatic' WOT shift points. Also available with $$$ AOD aftermarket valvebody...

 

[Art]

3. Normal shift pattern. AODs are 2-D-OD. To get an AOD to manually shift 1-2-3 you have to do the '2-D-2 shuffle' which is hard on the trans internals... unless you spend $$$ to get an aftermarket electronic o/d lockout valvebody....

We must have had different AOD's

 

[Cougrrcj]

Well, on Mustangs and maybe other chassis cars the shifter is labeled 1-D-OD, but it is all the same thing... 2-D-2 shuffle is Hold down in lowest position until desired RPM, then momentarily shift to D to force the shift, then pull back down to lowest position for manual Second, then when desired shift point RPM is reached, move shifter to D.

With my current engine, valvebody and governor, if I leave my shifter in D the 1-2 shift occurs at around 4300rpm, and the 2-3 at 4100rpm. ETs are almost a full second slower than if I manually shift at 5500rpm.

Doing the 2-D-2 shuffle somehow applies the OD band in manual Second or some such thing... At least that is how I've seen it explained... It is all in how the trans gears work...

 

[JoeShuck]

Joe,

Have you read my thread?
http://www.mercurycougar.net/forums/showthread.php?50657-4R70W-AOD-Swap-Details

I read through your thread an I do need to know a few things. Where to get the crossmember and if that one guy(poor reference) has fabricated a shifter that I can just purchase outright. I just need to make the swap as easy as possible. I don't think the shop I have the car at had every swapped that tranny into a 68 cougar and I am afraid if the hang-ups that ALWAYS happens during swap/shop experiences.