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Discussion Starter #1
I have a few questions about the 4R70W in V6 Mustangs. The reason I'm asking is that it's come to my attention that M5R2 parts are becoming rare and expensive, whereas 3.8 4R70Ws are a dime a dozen. Anyway, here are my questions:

1. How much weaker than the 4.6 4R's are the 3.8 versions?
2. Is there a range of years that are better to get, like 99+ for the V8 trannies?
3. What are my options as far as torque converters? Can I use the converter from my current transmission (A Marauder converter)? I have a feeling the answer here will be no... :(
4. Are there any flywheels that I can use? I need one with a 28-oz. imbalance.
5. I'll use a standalone controller, probably the Baumann TCS. Is this going to do a good job of it?

If anyone can help me out with these questions, I'll really appreciate it. Thanks!

-Steve
 

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Discussion Starter #3
Yeah. I know the 3.8 tranny won't bolt up to a 4.6, but I've got a 351 Cleveland that I'm going to drop in this summer, and I need to choose a tranny to back it up. I'd prefer a manual, but a T-5 won't hold that much power without a lot of expensive modifications (from what I hear), and M5R2 parts are getting hard to find. If I'm going to have to have an auto, I'd like to have the 4R70W, since I'd like to keep a tranny with overdrive and a lockup converter, and an AOD just won't cut it either. So, I guess I'm just weighing my options here. I can still get the M5R2 rebuilt, but the better blockers aren't available anymore, and all that. Plus I already have experience with the 4R70W and all. So I don't know, just looking for some info.
 

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the only difference between the v6 and v8 4r70w in terms of strength wise is that the v8 version has 1 extra clutch plate than the v6 one. the rest is being the same. read it on here 2 years ago.
 

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I'd use a V6 trans from a 01-02 stang as a starting point, and add a few clutches to it to hold up to the 351C power.
 

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Discussion Starter #6
Thread resurrection! Does the 4.2 4R70W have the same clutches as the 4.6 4R70W? The 4.2 does have the same bellhousing pattern as the 3.8, right? The only M5R2 I can find locally has over 200K on it. I'm thinking I'll use the 4R70W for a while then do a T56 swap in a year or two. :D
 

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The '98 out of a 4.2 f-150 I bought had the smooth intermediates and the old style direct clutches. '99 might have the upgraded direct clutches. The only application for the grooved intermediates and thicker direct steels with thinner clutches in '98 was a 5.4. I read the valve body doesnt jmod well. It has the same bellhousing as a 3.8. Upgrading anything inside a '98 truck 4r70w other than the valvebody and converter is probably overkill. The one I gave $250 for could have been used as is.
 

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icantdrive55 said:
The only application for the grooved intermediates and thicker direct steels with thinner clutches in '98 was a 5.4.
:confused:
All of the 98 transmissions I have taken apart have the upgraded clutches.
 

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Discussion Starter #9 (Edited)
I would be getting a 99+ 4.2L tranny. That would have the mech. diode one-way, right? I just wanna make sure this thing's not gonna grenade after a few months. I'm looking at 350-400RWHP, and in addition I'll also be spraying a little shot of happy gas, maybe 100 or 125. I'd rather have the M5R2, honestly, but I know the 4R will be faster and more durable, and cheaper and easier to put in (all's I need to do it is a Baumann TCS and a TPS), not to mention it'll eliminate the hassle of finding a flywheel and clutch, and hanging the clutch pedal. I just really want a manual!! :(

Edit: So I would also need to replace the VB with one out of a 99+ Mustang or the like?
 

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I'd still get an 01-02 V6 mustang transmission. The 4.2L version may have a different VB from the mustang one. As far as the clutches go, all V6 4R70W's from a given year should be about the same from chassis to chassis.
 

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I guess mine was an early '98 and they were using up the leftover parts. I'm not sure about the directs but the grooved intermediates are for a 5.4 only. Kinda sucked having to spend almost 70 bucks on clutches at the dealer. I was planning on reusing the frictions and the steels for sure since it was low mileage.
 

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Discussion Starter #12
Well from what I've read, the 4.2L 4R70W has the same number of clutches as the V8 one. Swapping the valvebody is no big deal, I know how to do it already. I don't, however, know how to add the extra clutch to the 3.8 4R. Plus, valvebodies aren't that expensive anyway.

Are the 4R's from a 4.2 Econoline the same as the 4.2 F150? I found one about an hour away with 27K on it for just $550.
 

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A new VB is over $200 from Ford, for a bit more than that you could just have a V6 stang trans and be done. You will need an F7AZ-7B066-AB pressure plate, and one each of the friction F8AZ-7B164-BA, and a steel F6AZ-7B442-AA. Then check the end clearance - if you have a feeler gauge around like you use for setting spark plug gap, that will work. Set it to about .080". If the gap is off, you just get the proper snap ring to fit.

I can't verify about the 4.2L's having the 6 plate direct or the 5 plate direct clutch - maybe one of our V6 experts will know. It appears that may be so, since Jerry's article says 3.8L (so the 4.2L variation may be different). If it does have the 6 plate, then maybe you can find a nice used 01+ VB somewhere online for cheap.
 

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My '98 4.2 tranny had 6 directs and 4 intermediates. Like I said they were the old style directs and smooth updated intermediates. '99 truck should have the better direct clutches. Even then 6 of the old style clutches would be plenty. It's actually easier to mess with the guts than the valvebody but I guess experience is what makes it that way. It wouldn't hurt to inspect a used tranny and the Mustang transmission would probably end up cheaper that way.
 

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Discussion Starter #15
I haven't actually heard it from any sources I know that I can trust, but a lot of sites about restomod 4R conversions have said that the 4.2 4R has 6 clutches and is recommended for builds with 289/302/351W/351C powerplants.
 

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Darrin said:
:confused:
All of the 98 transmissions I have taken apart have the upgraded clutches.
Darrin,I tore down and built a 3.8L Stang 4R70W that was out of a '98 a few weeks ago.It had 3 smooth intermediates,and the older directs(5 clutches),and it had a production date stamped on the case of 10/28/98.
Also had the small OD servo,and the low pressure EPC.
JL
 

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Discussion Starter #18
Ok, so how difficult is it to add the extra clutch? Is it something I would be able to attempt myself, or would I be better off letting someone else do it? I think I'll take everyone here's suggestion and add a clutch to a 3.8 tranny instead of changing the VB on the 4.2 one. Mainly because the 3.8 trannies are about $200 cheaper - I found one semi-locally with 32K for $350.
 

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Since we're on the subject, did the 3.8 swith to the 4R70W in 94 or did it do it later?
 

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4 Cam Bird said:
Since we're on the subject, did the 3.8 swith to the 4R70W in 94 or did it do it later?
In the T-Bird it did! :)

I'll ask a question now!

Will a 2000 V6 Mustang tranny require a speed cal in my car? ( newbie question!)

Joe
 
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