Danny

iTrader: (16)

Hey guys,

I just bought a TH400 for my Fbody. I want to rebuild it to within stand 1000hp. My car will actually only be making 750RWHP but I want room to grow. I'll be running a TB, MVB & a nice cooler.

My question is, what internals should I go for? Most tell me Red Alto clutches. Is there a good off the shelf kit for an application like this?

Thanks

PS: I'm kind of on a budget so lets not go crazy.

Jake's Performance

iTrader: (2)

The Alto clutches are not really any better than the stock clutches IME.

1000 HP TH400 from us would be a billet input shaft, forward hub, intermediate shaft, 36 element sprag super drum, Griner transbrake, deep pan, 6 clutch direct, 5 clutch forward, 4 clutch intermediate, rollerized, with other proprietary mods.

I think you'll find you may be able to buy a built unit for what it would cost you to build one.

Pretty serious setup.

Danny

iTrader: (16)

I'm sure some will recommend buying a built trans but I rather build it myself and learn. If I break a built trans I'll be back where I am now. If I build my own I can always build myself another. If racing has taught me anything it's taught me that nothing is unbreakable.

Thanks for the advice though. At least I know what to start looking for.

Jake's Performance

iTrader: (2)

I encourage others to learn to build their own auto trans but at the 1000 HP level, the learning curve is steep, expensive and can even be deadly.

Danny

iTrader: (16)

I see your point. I guess I'll have my buddy look over my build. He's done quite a few TH350 & TH400 but he's hard to get ahold of.

midwestjunk

iTrader: (2)

I just had a th400 built last month rated for 1,000hp. it is a 8 bolt pump, billet forward hub, direct drum 34 element sprag, alto red clutches, roller bearing rear section, hipster RMVB w/ trans brake, JW Ultrabell, deep aluminum pan. I paid $1,800 and they supplied the core.

The upgrade to the billet shafts and fully rollerized really jumps the price up so I declined that. I was told it was not neccessary for my application, but it would definetly be better. the 1,000 hp is at the far end of what my car will end up making next year anyway.

Danny

iTrader: (16)

Can all these upgrades be simply bolted on or is there any machining needed to make some parts fit?

Rumble

One of the best things I ever did was visit www.idealhowtovideo.com and buy their High Performance 400 Turbo info.

SnIpEz

iTrader: (4)

No hate man but if you have to ask questions like that I highly don't recommend trying to build your first transmission to withstand that kind of power. If you truly want to learn, try a stock rebuild. Tear it down and build it back up. There are hundreds and hundreds of components in an automatic transmission and it's very overwhelming for somebody brand new to it.

My prediction is you will be able to tear it down fairly easily enough, but you will get far in over your head and it will became very stressful. Unlike swapping an engine where you can have a few extra nuts and bolt left over and everything is still 100% fine, you cannot have ANYTHING left over after building a transmission.

Let's say you do manage to build the transmission. Without working in a shop with a transmission dyno, the only way you're going to be able to test that unit is by installing it in your car and driving it. It's very common for there to be too much or too little line pressure with a transmission after it's first built, even professionals have it happen. There are pros who can build a transmission and test it out, find out is has irregular pressure and tear it back down and STILL get their *** kicked trying to figure out what caused it.

Extensive prep work needs to be done cleaning the unit, and if you are buying a core you never know what could be wrong with it. Again, no offense, but you have an untrained eye when it comes to transmissions and it will be virtually impossible for you to be able to spot any irregularities on a shaft's splines, or with any of the other components that render it useless.

I highly recommend buying a transmission from a sponsor. I'm not a sponsor and I don't own a shop so I do not benefit from recommending this, but trust me, when it comes down to it, it's much more cost effective than you may think, it's faster, it's WARRANTIED (that's a big one right there, warranty\ies vary shop from shop) and you can rest easy knowing it's built right. Every shop has their own little tricks and twists on transmissions which really give them their flair.

I don't mean to make this sound intimidating, but if you're shooting for a transmission that can hold 1000 rwhp RELIABLY, then making it your first build is honestly a very terrible idea.

96gtdan

iTrader: (6)

I say if you want some tranny like that leave it to the experienced! I have friends with Jakes performance units and no problems! That's the way I'm going on my turbo build! Nothing beats proven builders and warranty to back it up!

SnIpEz

iTrader: (4)

^ X2 for Jake's Performance, those are very very nice transmissions, built by the best IMO.

StraightTimeStirrups

Two doors down from my shop is a shop that builds Turbo 400 Transmissions for the Off Road Racing Crowd! The cost, $40,000.00 and they work on them ALL DAY LONG 5 days a week! It blows me away how much work they have! When they rebuild rear ends, the Ring and Pinions alone sell for $3500 a set just for the Ring and Pinion!

OUCH!

Joe

Danny

iTrader: (16)

Thanks everyone for your input. I really appreciate it. My setup will be making 525RWHP on the motor alone so I'm going to take a stab at building my first TH400 w/ all the basic upgrades. I have a few days off coming up so I'll be tearing the trans apart and putting it back together. Just for practice and to get familiar with everything. I'll be sure and post my results once I'm done.

Thanks man. That video looks interesting. I think I'll order me a copy. Did the video really get into every part of the trans or just the basic of rebuilding?

SnIpEz

iTrader: (4)

Judging from the length of the video, I'm assuming only the basics of rebuilding. It would take a lot longer than that to get into every part of the trans.

525 rwhp is a much better idea IMO, these transmissions are pretty stout in stock form. Keep in mind what I said about testing your trans though, you'll never know if you have too much or too little line pressure on your transmission until it's too late unless you can find a place that will let you dyno your trans. Dyno can catch a LOT more than just line pressure, but that's the most common thing to watch out for.

Fbodyjunkie06

iTrader: (10)

Jake this is Martin I bought a manual valve body and brake from you back in May we talked on the phone after the sale due to my bad wiring, but you sent me another black box for free anyways, guy's Jake is the real deal when it comes to making sure his customers are taken care of. I would never turn down advice given by jake or his products, stand up guy. Loved the valve body and the brake btw, but I sold that car and I have a car with a TH400 now.

My current trans has everything you mentioned above aside from the billet hub, input shaft and 36 sprag. It has the 34 sprag 6 clutch direct, new steel hub, 5 clutch foward, and 4 intermediate, rollerized, snap ring mod, etc. etc. I've heard this is good for 750 ft. lbs. tq....what do you think it will hold? I have been footbraking the car, but I have a transbrake I want to put in. Car only has 405rwhp and 350rwtq and weighs no more than 3000# race weight. Going to spray it soon. Let me know through PM so we don't clutter his thread. Thanks.

StraightTimeStirrups

Knowledge isnt clutter!

Jake's Performance

iTrader: (2)

If its assembled correctly and the hydraulics are right, it should be happy to the 750 HP/TQ range.
The stock shafts in a TH400 rarely fail. They live up to the 1000 HP level but I like to upgrade the input shaft and sprag/drum around the 850-900 range depending on vehicle weight, power adder, etc.
The forward hub is the weakest hard part but a later 4L80 piece is slightly better or a billet steel one is the best choice.
It will work fine for you.

tt383lt1

iTrader: (3)

im not the smartest guy with transmission but mine has straite cut plenitary. billit input and output shaft. bigger drum for more clutches, kevlar clutches, 34 or 36 sprang. pro tree valve body w/ brake. what do you think the horse power level is. I got told 1000+ is that right and i bougth this about 3 years ago. i think there is more in it but not sure.

tt383lt1

iTrader: (3)

oh and why do you put a straite cut plenitary in?

Jake's Performance

iTrader: (2)

Some builders use straight cut planets because there is a common myth that they are stronger. They are in fact weaker than helical and don't lubricate as well. We rarely use them. Only in very heavy applications where we want to eliminate thrust loading from the helical gears.

There is a huge difference in a 34 element sprag and a 36 element sprag.
The 34 element sprag was a common upgrade using an early TH400 drum and is stock on later 4L80Es.

The 36 element sprag is adapted from another application.
It requires a custom drum to fit because it is larger in diameter, has 2 more holding elements, and the elements are. 450" wide instead of. 330".

It would be hard to estimate power capabilites without an accurate description of the parts list. Then there are quality differences in the parts.

We've seen inferior "billet" shafts that were weaker than stock. We have also used almost all the various manufacturers aftermarket parts for a TH400 or 4L80E.
I select which parts are best. There are several manufacturers of most of these parts. We don't use what is cheapest, we use what is the highest quality. TH400 foward hubs are a good example. We don't use the common Sonnax piece that most builders do. Its cheaper and more commonly available BUT we custom order ours in bulk to keep pricing down. Ours are noticeably beefier than the Sonnax part. We don't see the frictions beat ours up over time like some of the others.