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Discussion Starter #1
Long time reader here got a lot of info for my 1st turbo v8 build from these forums, now im doing another build and need some help from you guys :)

Car is ls1 powered and maybe turbocharged down the track. I drive it hard power skids / burnouts etc etc. Want to go th400 got a core with the following codes

74 CJ

looks like its from a 1974 454 V8 Series 30 ???
If it hasnt been hacked with is this any better than a car th400? ive been told it is?

Now im located in Australia and most trans shops ive called charge drug money for a th400 to hold 600hp with a 34 element sprag they want around $2700+ or so aus dollars and thats with me supplying the core. A 400 core is worth $400 here its crazy !!

Now i have done a lot of reading on the net downloaded and printed of the atsg 400 book.
I want to give rebuilding the box a go myself. Im not bad on the tools and a lot of people say the 400 is one of the easier boxes to rebuild.

Just need you guys opinion on what kits i can buy that are decently priced. As its my 1st rebuild i dont want to go crazy all out.

Will something like this with a 34 element sprag and drum be good for say 600 -700hp ?

http://www.ebay.com.au/itm/8075007687?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I know jakes performance is on here and if i do the mods he says / has listed on his page the dual feeding etc etc for t400 will it hold up?

Any help will be appreciated
 

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You won't know whats in the trans until you tear it down. Try to stay away from a unit with an output shaft with threads/bolt on yoke. Make sure it has all aluminum pistons not steel.

Get this or one like it instead save yourself a few $, http://www.ebay.com/itm/GM-TH400-TRANSMISSION-REBUILD-KIT-WITH-STEELS-34006A-/350131886407

You don't need any fancy friction or wider bands for 600-700 HP IMO. Be sure to get good quality OE Borg Warner or raybestos friction and bands in your kit.

Yes you'll need to upgrade to the 34 element sprag and drum.

Yes at minimum do the dual feed mod and enlarge the feed holes in the separator plate.

You can add a turbo 350 pump bearing and .015" shim in place of the output shaft steel thrust washer and planet thrust washer.

Do some searches on 400s on here, lots of good info.

Good luck on your build
 

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Discussion Starter #3 (Edited)
Thanks heaps for the info mate. Great help.
It don't say in that add that it uses Borg Warner clutches? Does the transtec kit included Borg Warner clutches?
Should I change any of the bands or bushing at all? Or should I wait till I pull it apart and see what they are like ?

This gearbox has the output shaft with the bolt hole in the middle tho it was fitted to a car before I got it
 

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As others have posted, tear it down first then determine what parts to order and make sure you get a yoke that works with that output shaft.
 

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YOU NEED A GASKET KIT WITH TEFLON RINGS,. OUTPUT SHAFT CAN BE MODIFIED TO WORK WHEN YOU HAVE IT APART. HUTCH HAS A GOOD STOCK DRUM , MODIFIED FOR RACING. GET A BUSHING KIT ALSO.LIKE SAID ABOVE, YOU WILL NEED TO RIP IT APART AND SEE WHAT ELSE IT WILL NEED.
 

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Discussion Starter #14
Ignore the post above just googled for some info
So any kits that are not 2 expensive you guys can recommend ?
 

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I don't use kits (that have clutches,steels, and bands), i would tear it down and fix what needs replaced/upgraded. bushing and seal kit isnt a bad idea though.
 

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Discussion Starter #16
462chevelle Just trying to get a basic kit. As here in aus if i walked into a transmission shop and asked for any of the bits inside a t400 id be paying double the price of what yous will be over there.
Most trans shops dont even know what a 4l80 is here
Nothing we got here comes with a 4l80e from the factory. US pickup trucks are very rare and expensive
Found one shop that would do a 4l80e me. With me supplying the core they wanted $3700 (just for box) for a rebuild and wouldnt warranty it if it was used behind any performance or tuned car.
 

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Start with a paper and rubber kit with Teflon rings.

Add a brass filter, and since it sounds like getting parts might be a pain in the ass for you - I would
Order a bushing kit too.

However, the best benefit would come from tearing down the trans you have first to see what it needs. You know you are going to need a paper and rubber kit. But everything else is up in the air until you get it apart.
 

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Discussion Starter #18
Yeah looks like i might have to pull it down. Il look over it in the next week then get back to you guys if i need a hand with anything. Thanks for your help so far
 

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Discussion Starter #19
Hey guys finally pulled the box down.
Orded this kit below with a borg Warner 34 element sprag.
http://pages.ebay.com/link/?nav=item.view&alt=web&id=8075007687

Bought a drum to suit locally

Gonna do jakes dual feed mod and firmer shifting mods.
The rest of the box looks good inside or the old clutches steels where good.

The kit come with a sonnax no walk bush. I've replaced the bush on the pump but is the sonnax one just a simple knock out the stock one and fit the no walk one ?

Any other tips ?
Thanks everyone for your help so far
 
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