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Which valve body and torque converter should I get?

11236 Views 7 Replies 2 Participants Last post by  acgarib
Hi, i'm thinking of getting a better valve body and torque converter for my AOD.

I was thinking of getting a Lentech valve body, but I'm not sure of which one. The street terminator seems OK, maybe calibration #2. (or calibration #3?)

I have some questions about the valve body's overdrive switch. If I just keep the switch deactivated so O/D is never locked out, will it shift like a tranny is supposed to do or will weird things happen? (I read a post somewhere saying that keeping the switch off will make second gear do engine braking, then when it shifts, it goes directly into overdrive.) I don't want to have to keep on pushing a switch when I want to go into and out of overdrive.

I've heard good things about Precision Industries' torque converters, but they are pricy. Any other good, but cheaper brands?

Also, apparently people like to replace the overdrive servo with a A+ servo when they replace the valve body. How can I tell which servo I have and is it even worth it?

I'd really like it to go WOT in overdrive because with the 4.10 gears, my top speed is 100 mph in 3rd. If I do any mods to the engine, I will start running out of rpms too soon. Will replacing the overdrive servo then getting the right valve body enable me to go full throttle in O/D?

My stang has a stock engine, full exhaust, and 4.10 gears. It also has 133,000 miles. I don't drive it much, and almost never drive it on the highway.

So I guess all of this boils down to: which Lentech valve body and torque converter brand would be good for mostly street/cruising? What stall speed should I get? Should I get a lockup or non-lockup converter? Should I get an A+ overdrive servo? Is the servo worth the money? How can I check to see which servo I have? Is there any way to go WOT in overdrive without burning up anything?

Sorry for the huge ammount of questions.

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I'll go in order.

You have to decide first if you want full manual control, or if you want automatic shifting as well. That's when you have the levels to choose from.

What's the purpose of getting a valvebody if you want it to shift itself? The Lentech valvebody changes things, and you will have to have a button for overdrive unless you get a different name valvebody like Art Carr, Performance Automatic, or Dynamic.
If you're thinking about the manual version, you lock out overdrive then you won't have overdrive. If you lock it on and then stop, you'll take off in overdrive. How else do you expect to change gears without a button for overdrive?

Precision Industries torque converters get a lot of publicity, and they're good. You could also contact Dynamic Racing Transmissions, they run Torque Converter Technologies and can make you a converter that'll match everything you've done to the car. Proper converter selection shouldn't be based on stall speed alone... like I see so many do.

If you have a Mustang with a stock AOD, then you have a B servo. I think the servo has the letter stamped on it, you can't miss it. The A servo is from the Thunderbird Super Coupe and it applies more clamping force on the overdrive band for a more positive gear.

To get it to go into overdrive at WOT, you have to get the aftermarket valvebody because it's designed NOT to go into OD unless you let off the throttle.

The converter and valvebody will be good on the street, as long as you get the right versions of both.
The stall speed will have to be determined by the converter company, these will affect what stall you need...
engine size
camshaft specs
compression ratio
cylinder head flow
vehicle weight
rear gear ratio
transmission gear ratios
intended use of the car
Be prepared to provide those answers when you start the process.

The A overdrive servo is recommended. You would have to take the pan off, take the valvebody out, take the servo cover out, all to see the servo. If it's a stock AOD in a Mustang, you have a B.

To get it to go into OD at WOT, you have to change the valvebody to one where you control the shifting.
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Thanks EagleAutosports,

I was thinking of getting an automatic valve body so when I don't feel like shifting, I can just pop it onto O/D and drive like normal, but when I want to shift it my self, I can.

Ideally, I'd like a fully automatic valve body in the "over D" position with overdrive not locked out, but have full manual control when I lock out overdrive and switch it to 1, D, O/D, then hit the O/D switch.

For normal driving, I'd like to be able to just drive like I do now when the AOD is in the O/D position. (Just keep O/D enabled all the time) I don't want to hit the O/D button constantly when I get up to speed then slow down.

Then for the 1/4 mile, I'd like it to not go into overdrive until I disengage the O/D lockout switch. Of corse needing O/D in the 1/4 mile won't be a problem until my 'stang gets more power. :scratchchin

If I do get a valve body that enables WOT overdrive, and I change the servo to the A+, will I still have to upgrade other components deep inside the tranny, or will upgrading the servo be enough to prevent damage or premature wear? If I have to do anything too complicated to beef up the tranny for WOT O/D, then I'll just forget about it and stick with a cruise only O/D.

Does the Lentech street terminator do all of that? (Enable WOT O/D and behave Iike I described above?) If not, are there any other configurations/ brands that do?

Oh, and another question: do these aftermarket valve bodies shift instantly or near instantly when I move the shifter to the next gear? Currently, when I shift from 1 to D, it takes time to go to 2nd gear. Sometimes it happens fairly quickly, but sometimes it takes a while and I have to let off the gas to prevent the rpms from getting too high.

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I'm back with more questions. I talked to my mechanic for a estimated price of install (he specializes in transmissions) and he said that he would install the torque converter, valve body, change the governor in the tail housing, and completely take apart and inspect my tranny/ replace anything worn for 900. (doesn't include price of converter and valve body) That's a good deal right?

I have a question about the governor. He said it raises the shift points, but will this, combined with the Lentech valve body, make the AOD shift at too high a rpm? What about getting a 2" O/D band. Does this raise shift points also, or does only the 4R70W gearset do that?

Also, while my mechanic has the tranny in a million pieces, should I go ahead and buy the A+ overdrive servo and maybe the 2" overdrive band so he can install that instead of the old stuff? Will this make overdrive strong enough that I can use it at WOT? Is it possible to order a Lentech Street Terminator valve body that enables full throttle O/D?

OR, instead of spending all of this money building up my tranny, should I just get a whole new Lentech AOD? The only problem is the Street Bruiser and Street Terminator both can't do full throttle in O/D and aren't lockup capable. Is non-lockup bad for street and does it produce too much heat?

Sorry for even more questions. It seems the more I look into this, the more questions I have.
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Sorry dude, I didn't know you responded till now.

Lentech makes multiple styles of valvebodies, I cannot remember which was which but they do make a unit to perform the way you want. I think the Terminator is full manual, it'd be best to contact them to get the one you want, plus making sure of getting OD at WOT. Go with their recommendation.

To put in an A servo, you just remove the B and replace with the A.

Stock valvebodies were designed to give smooth shifts, because it wasn't meant for performance applications. You change the valvebody to a better unit, you'll get instant shifts with no lag between.

$900 for install isn't bad.

The governor does affect the shift points, if he knows what he's doing then he could get it the way you want. As long as he doesn't drill it to change the weights, which is the WRONG way.

The 2 inch band is good. It doesn't affect the shift points, neither does the gearset. The throttle valve cable and governor controls that.

A new Street Terminator would do fine on the street, they could build it however you want it to be.

Difference between lockup and non lockup...
Lockup: usually used to increase gas mileage by locking out the converter in 3rd and 4th. The converter won't be multiplying the engine torque, resulting in less slippage and less heat. This uses a two piece input shaft, which is weaker. Lockup transmissions are known for breaking these two shafts when coupled with lots of traction.

Non lockup:
Uses a single, big, beefy input shaft which means higher strength. This requires a non lockup converter which costs more along with the expensive 1 piece shaft made out of steel. This converter will multiply the engine torque in all gears, making the car faster but it does create slightly more transmission heat. This also means slightly less gas mileage, due to the muliplication.

I use a non lockup AOD with full manual valvebody and can say it works fine in a daily driver. I've driven it cross country too.
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What about silverfox stuff?

His valve bodies and transmissions are recommended on clickclick and corral, and are significantly cheaper than Lentech's stuff.

I could get a SPT-R valve body for $230 instead of Lentech's street terminator at $545 and they both seem to have the same features.

I could get a silverfox transmission (AOD-700) for $1900 or so instead of Lentech's $250.

Is there something that the lentech stuff has that the silverfox stuff doesn't have that makes it so much more expensive? Do the Lentech trannys come with torque converters and the silverfox trannys not?
I have no experience with Silverfox, so I cannot make a fair assessment of them. Maybe someone else has?

As for Lentech being so expensive, you're also paying for it to come in from Canada, which is quite a bit for the import tax.
Ok, after doing more research and talking to my mechanic again, I think I'm going to have my mechanic rebuild my tranny with better parts while he has it out to install the PI torque converter and Silverfox valve body.

He recommended a lower stall converter than the numbers i usually see thrown around the mustang forums. He said 2500 rpm max because of my 4.10 gears and high torque in the low rpm. He said any higher and I'd have to always give the car a lot of gas to get it going.

The people online always seem to say at least 2800 rpm.

The other thing I am not sure of with the converter is lockup or non lockup. If I go lockup, I'll need a better inner input shaft, so keeping lockup would cost more. Do you guys think having lockup in 3rd and 4th is worth the extra 160 dollars for a hardened input shaft?

I also asked him about correcting my speedometer. Right now, there is no speedo gear with enough teeth that will correct my speedometer. I need to get a tailshaft with a 7 tooth drive gear instead of my current 8 teeth. Is there any particular tailshaft that is the best? I know mustang tailshafts had a revision in '88 that made them last longer, but they also changed to the 8 tooth gear that year. Is there any tailshaft that is durable (lube mod?), strong, had provisions for the governor, and has the 7 tooth gear? Is that what the '93 Mark VIII tailshaft is? Any other models or aftermarket tailshafts available if I can't find a '93 mark VIII tailshaft?

I was thinking of having my mechanic install this kit from broader performance for $485:
"Complete upgrade package. Includes new stamped steel direct drum, intermediate clutch upgrade kit, large billet overdrive servo (Sonnax brand), wide Carbon overdrive band, mechanical diode sprag, reverse drum and sun gear."

Does that "upgrade kit" include everything for a good upgrade over stock without going too crazy? Do I need anything else to make that kit compatible with my AOD?

I did a price estimate for all of this and it came out to about $2300 give or take a few hundred.

Or I could get a 450 HP capable $1350 tranny from Silverfox plus a $600 PI torque converter installed for $2325.
I could also get a 700 HP capable tranny from Silverfox for 1900, the same converter, and get it installed for 375 to come out to $2875

the 450 HP tranny:

- Pump and stator modified for increased cooler flow and lubrication

- 300M hard input shaft (retains direct drive function)

- Raybestose High Energy clutches (3 INT, 4 REV, 5 FWD, 6 DIR)

- Cast drums with greatest capacity

- Heavy duty Kevlar overdrive band

- A+ billet overdrive servo (greatest holding capacity)

- Updated accumulators

- Heavy duty intermediate roller with improved snapring-Lube mods (force lubricated high heat or wear components for greater reliability and service life)
-SPT-1 Series or R Series valve body (see Valve Body section for details)

- Chrome pan with drain plug

- High-temperature aluminum paint finish

I guess it looks like I can get more for my money if I have my transmission guy rebuild my tranny than buying a new one.
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