which TH400 to get

[porsches4lunch]

I'm thinking about going TH400 but have not been able to find on here, which model is best to use. Also, does it just bolt in or do i need any kind of adapter plate do i need a new drive-shaft ?

 

[pacecarta]

as far as trans is it has a shortail with BOP bellhousing it will bolt right up , if its chevy pattern youll need an adapter or to convert it with an ultrabell SFI housing , if big hp is the goal the ultrabell housing is a good idea anyway
i would source the trans from a buick trans builder built for your goals not one you found on craiglist or local boneyard.
trans mount needs a little work to use the one from the 2004r or you can get a poly kit from hrpartsnstuff, crossmember stays where it is
cooler lines can be bent to fit or change them over to -6AN
the driveshaft will need to be shorter aprox 1" ( 50-1/2 center to center with an 8.5 rear ) but you really should have the trans in your car and measure for size depending on yokes used , id recommend going to an aftermarket 1350 ujoint shaft
the stock shifter can be made to work with a selector plate from gbodyparts or go aftermarket


and youll need a converter

 

[porsches4lunch]

as far as trans is it has a shortail with BOP bellhousing it will bolt right up , if its chevy pattern youll need an adapter or to convert it with an ultrabell SFI housing , if big hp is the goal the ultrabell housing is a good idea anyway
i would source the trans from a buick trans builder built for your goals not one you found on craiglist or local boneyard.
trans mount needs a little work to use the one from the 2004r or you can get a poly kit from hrpartsnstuff, crossmember stays where it is
cooler lines can be bent to fit or change them over to -6AN
the driveshaft will need to be shorter aprox 1" ( 50-1/2 center to center with an 8.5 rear ) but you really should have the trans in your car and measure for size depending on yokes used , id recommend going to an aftermarket 1350 ujoint shaft
the stock shifter can be made to work with a selector plate from gbodyparts or go aftermarket


and youll need a converter

Thanks

Exactly the info i was looking for!!!!!!

 

[pacecarta]

forgot to mention besides the length on the driveshaft you need a yoke for the trans output
the trans output yoke on the th400 is different from the 200-4r , the 200-4r uses the small diameter yoke and shaft spline as the th350 and 700r4, the th400 yoke is larger and is same as the BW4spd
most upgrade to the th400 because they feel they've reached or already exceeded the limit on the 200-4r for continuous high hp duty , even though the 2004r can be built to survive into the 9s it doesnt seem to do it long before needing a refresh.

if this is just for a change of pace or for money reasons to replace a defunct 2004r since they can cost some coin to rebuild then a full out race built 400 might not be needed but when gearing up a th400 for high hp it will need some selected parts in the build to survive even for just low 10s with a 3700lb car , and if tbrake launching youll need a stout driveshaft. the dennys nitrous ready 3.5" shaft can run near 800.00 and then theres the converter which youll want to be sure it has anti-balloon plates (avoid cheap low budget converters)
when you go to a 1350 driveshaft you can either get a conversion ujoint at the rear to the stock 8.5 3R44 or if you plan to run a transbrake and launch hard i would change the rear pinion yoke to a forged 1350 and get the shaft with all 1350 joints
, with the shaft the yokes and converter the th400 swap is not such a budget swap over a 2004r rebuild anymore but for high hp these parts would have to be upgrade whether you ran a 2004r or a th400,

also have to be careful of thrust damage due to high cooler line pressures which is why i say dont just bolt any th400 up , go to a buick turbo trans builder who knows how to prep the trans

if your plans arent over the top hp theres also the th350 as an option , the th350 can handle some power as a few have done well with them running low 10s into the 9s if built right and with a short tail th350 you can use the 2004r driveshaft as is , but requires a crossmember from an older gbody

 

[toofastforyou]

if big hp is the goal the ultrabell housing is a good idea anyway

trans mount needs a little work to use the one from the 2004r or you can get a poly kit from hrpartsnstuff,
cooler lines can be bent to fit
the driveshaft will need to be shorter aprox 1" ( 50-1/2 center to center with an 8.5 rear ) but you really should have the trans in your car and measure for size depending on yokes used , id recommend going to an aftermarket 1350 ujoint shaft
the stock shifter can be made to work with a selector plate from gbodyparts or go aftermarket


and youll need a converter

Paul, I'll probably end up doing most of what you just wrote...J&W Ultrabell, H&R 200-4R-to-TH400 transmission mount, urethane crossmember isolator bushing kit, etc...Brian Cotton surely knows what to do about the cooler lines and driveshaft lenght. Since I already have a custom heavy-duty driveshaft with 1350 u-joints, it'll problably be just a matter of having it shortened a little and change the transmission slip yoke.
For the shifter, I bought a reverse pattern, 3 speed shift gate plate for my B&M Pro Stick shifter, so no big mods needed there, and last, I'll likely be going with an ATI "spragless" converter, not sure about which stall speed, but I'll take Jack's advice for that.
I think that I have most of the important stuff covered...

Claude. :wink:

 

[porsches4lunch]

forgot to mention besides the length on the driveshaft you need a yoke for the trans output
the trans output yoke on the th400 is different from the 200-4r , the 200-4r uses the small diameter yoke and shaft spline as the th350 and 700r4, the th400 yoke is larger and is same as the BW4spd
most upgrade to the th400 because they feel they've reached or already exceeded the limit on the 200-4r for continuous high hp duty , even though the 2004r can be built to survive into the 9s it doesnt seem to do it long before needing a refresh.

if this is just for a change of pace or for money reasons to replace a defunct 2004r since they can cost some coin to rebuild then a full out race built 400 might not be needed but when gearing up a th400 for high hp it will need some selected parts in the build to survive even for just low 10s with a 3700lb car , and if tbrake launching youll need a stout driveshaft. the dennys nitrous ready 3.5" shaft can run near 800.00 and then theres the converter which youll want to be sure it has anti-balloon plates (avoid cheap low budget converters)
when you go to a 1350 driveshaft you can either get a conversion ujoint at the rear to the stock 8.5 3R44 or if you plan to run a transbrake and launch hard i would change the rear pinion yoke to a forged 1350 and get the shaft with all 1350 joints
, with the shaft the yokes and converter the th400 swap is not such a budget swap over a 2004r rebuild anymore but for high hp these parts would have to be upgrade whether you ran a 2004r or a th400,

also have to be careful of thrust damage due to high cooler line pressures which is why i say dont just bolt any th400 up , go to a buick turbo trans builder who knows how to prep the trans

if your plans arent over the top hp theres also the th350 as an option , the th350 can handle some power as a few have done well with them running low 10s into the 9s if built right and with a short tail th350 you can use the 2004r driveshaft as is , but requires a crossmember from an older gbody

From what i understand, the TH400 can take alot in stock trim specially versus the 200r4.

 

[pacecarta]

From what i understand, the TH400 can take alot in stock trim specially versus the 200r4.

you're overestimating the stock th400 (and underestimating a brf 2004r)

stock th400 (if its healthy) is considered only good to about 400hp , above that it needs good rebuild and shift kit , making more than 500hp and you're going to need some good hard parts in there and most go to a full manual reverse valve body so theres constant pressure on the clutches

stock the th400 did ok behind those big blocks muscle cars of the 60s and 70s where 250-300hp was big hp ( thats 300 net not the overin flated gross rated hP figures) 400 hp was a lot .. a turbo buick with anything other than a stock turbo turbo can easily out do one of those huge 60-70s muscle car motors in both HP and torque , even stock turbo can get close to the 400hp number

the stock brf 200r4 can and has been well into the 11s but if 11s to high 10s are in the plans (about 400- 500hp) a good rebuild with a hardened drum and stator and a shift kit is considered mandatory , over 500 time for some good hard parts

for most considering the th400 over the 2004r are already low 10s into 9s making over 600hp , again the 2004r has been there with billet upgrades

 

[pressured]

good info here guys, i labored over swapping to a t400, be done with it and dont look back, the swap is not cheap but worth it, the car feels great with the t400

 

[toofastforyou]

..." and most go to a full manual reverse valve body so theres constant pressure on the clutches"

Paul, you remind me of a question I've asked several guys but for which I never got a clear answer...Why is it that most built TH-400's have that darn REVERSE pattern, MANUAL valve body? Isn't it possible to have one with a standard, FORWARD pattern, and AUTOMATIC vb? Also, I'm going to have a trans brake installed...is it because of this?...

and

good info here guys, i labored over swapping to a t400, be done with it and dont look back, the swap is not cheap but worth it, the car feels great with the t400

Thanks, you sound reassuring! :wink: Even though I'm going ahead with this swap, I sometimes have some concerns about driveability on the street, especially the fact of not having a fully "automatic" transmission anymore......I just hope that once it's done, I won't regret it!...:redface:

Claude.

 

[pressured]

Paul, you remind me of a question I've asked several guys but for which I never got a clear answer...Why is it that most built TH-400's have that darn REVERSE pattern, MANUAL valve body? Isn't it possible to have one with a standard, FORWARD pattern, and AUTOMATIC vb? Also, I'm going to have a trans brake installed...is it because of this?...

and



Thanks, you sound reassuring! :wink: Even though I'm going ahead with this swap, I sometimes have some concerns about driveability on the street, especially the fact of not having a fully "automatic" transmission anymore......I just hope that once it's done, I won't regret it!...:redface:

Claude.

Claude, unless you're cruising over 60 mph you will be ok. having the manual valve body is lots of fun on the street, like a stick without the clutch, Greg