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What TC for a TH400? What to add to it when being rebuilt? Whats the deal w/ manual valve bodies?

Discussion in 'The Garage' started by dawson444, Oct 22, 2003.

  1. dawson444

    dawson444 1/2 ton status

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    I am running a 330HP 350 behind my TH400. What torque convertor would you guys say to run? It is going to be mostly for 4 wheeling and I am adding a doubler if that matters.

    Also I am taking my TH400 to have it rebuilt soon. What would you guys say to tell my tranny guy to add to it? It has a B&M stage 2 shift kit in it, I think I am going to tell him to either leave that in there if he can (can he?)Also is there anything else you guys would say to add?

    Whats the deal with manual valve bodies? Thanks!
     
  2. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    Take the shift kit out, put a stock convertor in it, and have a reverse manual valve body put in. That way, the shift pattern is P-R-N-1-2-D instead of P-R-N-D-2-1. With the manual valve body, you will have to shift the gears unless you run the RPM's up high enough that it automatically switches the gears. I don't know if that feature still works on a manual body though. It may just hold it till you blow the engine.
     
  3. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    A manual valve body is the same shift pattern as stock. A reverse manual valve body reverses the order of the drive gears.

    Basically it's just changing an automatic to full manual control.
     
  4. dawson444

    dawson444 1/2 ton status

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    why take shift kit out? why a stock convertor?
     
  5. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    full manual valve bodies wont shift unless you make it. HInce FULL manual. I wouldn't put a full manual and definantly not a reverse because that gets annoying having to shift everytime your driving it. Your fourwheeling not doing the 1/4 mile. I would keep the stage 2 shift kit and go with a good HD converter from a reputable manufacturer. Stock stall speed would be fine if your cam isn't too big but If your only making 330HP I doubt it is too big anyway. If you want to shift it manually just use the shifter and put it in first and go from there and put it in D when you get tired or don't need to shift it manually anymore.
     
  6. dawson444

    dawson444 1/2 ton status

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    anyone else?
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I agree...absolutely no use for a manual valve body in a truck.

    The guy that built my tranny said that a shift kit would be rough on driveshafts and wouldn't install one in my tow vehicle, but in an offroad application he said it was a good idea, and I tend to agree.
     
  8. 75-K5

    75-K5 3/4 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    I think a stage 1 kit or something comparable would wreak much less havoc on a driveshaft than having no kit at all would on a tranny. U-Joints are cheaper than trans rebuilds. Of course a good cooler might make up the difference.
     
  9. 84_Chevy_K10

    84_Chevy_K10 Banned

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    Well I pull a 9,000+ lb trailer with that truck and the stock rebuilt TH 400 doesn't slip at all so I figured save the driveshaft and my back.

    If it was 4wd, I would have definitely put a kit in it.
     
  10. yunit

    yunit 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    The problem with reverse manual valve bodies is that they do not have engine braking. The only reverse manual valve body I know of with engine braking is the Art Carr and it is like $350.
     
  11. mudjunkie 82

    mudjunkie 82 1 ton status GMOTM Winner

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    A freind of mine who owns a Transmission shop said a full manual valve body is not good for a daily driver because it will have full line pressure from the pump at all times and this will shorten the life of it......
     
  12. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    [ QUOTE ]
    The problem with reverse manual valve bodies is that they do not have engine braking. The only reverse manual valve body I know of with engine braking is the Art Carr and it is like $350.

    [/ QUOTE ]

    TCI just came out with one for a 700R4 not too long ago that has the compression braking.
    [ QUOTE ]
    700-R4 Full-Manual Series, all years, reverse shift pattern w/ full engine braking 376015

    [/ QUOTE ]
     
  13. dawson444

    dawson444 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    but why stock convertor?
     
  14. gravdigr

    gravdigr 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    [ QUOTE ]
    but why stock convertor?

    [/ QUOTE ]

    Because you want to be making torque down low, and you should be making torque down low. Unless your motor is cammed for making torque peak at 2500rpm you are better off with a stock stall speed converter.

    JUst in case you don't know the difference a stock converter starts engaging at about 800 RPM. Which means at 800 rpm it starts turning the driveshaft. If you went with something like a racing torque converter that locked at 2,000rpm that means your engine would rev to 2,000 rpm before the driveshaft strats turning. Good for a jump off the line. Not so good if your torque peak is at 1,800 rpm.
     
  15. heavy4x4

    heavy4x4 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    What you said is not totally true. The stall speed is the speed at which the power/speed going in is equal to the power/speed going out. Torque converters actually act as torque multipliers at lower RPM's than stall speed.
    Kinda hard to explain, so I'll let HowStuffWorks do that for me. Click here
     
  16. XtrmChevy

    XtrmChevy 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    Stock converter works fine for me too. I have the full manual valvebody with reverse pattern, and I like it. With the doubler in use it is often very good to be able to start moving in second or even third gear. But it sucks to not have compression braking /forums/images/graemlins/frown.gif
     
  17. BigOrange90Jimmy

    BigOrange90Jimmy 1/2 ton status Premium Member

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    I say use the stock convertor and to take the shift kit out because I'm a "stock" kinda guy. If it can't work in stock form, then I believe you should replace the entire thing with something that can, as opposed to trying to polish it up.
     
  18. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    I put a TCI reverse manual valve body in my camaro's th400.
    I like it for a street/ strip car but i'd only put in the art carr valve body for a wheeler. The TCI manual valve body doesn't have compression braking in 1st or 2nd gear. Only 3rd gear will have engine braking. That is- when you're in 1st or 2nd and you let off the gas, it will drop down to an idle and will not slow you down, then when you stomp back on the gas it will free rev up until it catches the gear at the appropriate rpm to accelerate some more.
    A few good points with the reverse shifting valve body is you pull the shifter towards you instead of pushing it away from you to shift... You use the G' forces of the vechicle to pull the shifter into the next gear instead of fighting it and trying to push forwards while your being pushed back in the seat. Also 1st and reverse are only 1 click away instead of R-N-D-2-1, makes it easier when your wheelin and you need to shift from 1st to reverse.

    The B&M stage 3 kit i couldn't get it to work like a full manual so i bought the tci manual valve body.
    The thing is without a manual valve body, if you had a doubler and wanted to start out in 2nd or 3rd gear, you would have to acclerate, and get wheel spin so the governor pressure will have to overcome the spring tension on the shift valve before it will go into the next gear..
    With a manual valve body you can shift it in 2nd or 3rd and actually take off in that gear- the tranny won't automatically downshift and make you take off and wind out 1st before you get 2nd gear.

    You do have to take the th400 apart when you put in the tci manual valve body. You'll remove 2 seals on the center support in the very middle of the transmission, and you'll also leave out the 2nd gear band.

    /forums/images/graemlins/grin.gif
     
  19. yunit

    yunit 1/2 ton status

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    Re: What TC for a TH400? What to add to it when being rebuilt? Whats the

    [ QUOTE ]
    A freind of mine who owns a Transmission shop said a full manual valve body is not good for a daily driver because it will have full line pressure from the pump at all times and this will shorten the life of it......

    [/ QUOTE ]

    For a daily driver with a lot of highway use, the manual valve body is not needed, but more line pressure means more fluid flowing through the tranny, helping keep it /forums/images/graemlins/cool.gif.
     
  20. Shaggy

    Shaggy 3/4 ton status

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    My 2 cents - a full manual valve body with engine braking would be ideal for a wheeler, although a bit tiring for a DD. FUll maual reverse valve body would be better yet.

    My question, since we're on topic - I've been thinking about what I would use if I decided to go with an auto tranny, and have pretty much decided that I would want a TH400 with the aformentioned goodies (Full maual reverse valve body with engine braking), but I would also want to add a manual lockup convertor. Are these available for a TH400? Would they lock at a variety of different RPMs, that is, do they truly lockup whenever I hit the switch, and stay that way? I think that having all of these features would make for an ideal tranny for a crawler, aside from not being as reliable as a manual tranny...
     

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