A340E Buildup Information Thread

[spoolint78]

my buddy is putting down well over 700rwhp in his mk3 auto with a t72 turbo.
he's deep into the 10's around here.

He said something about increasing the line pressure.
anyone care to elaborate on what he means?

 

[IJ.]

In a 340 there's an internal adjuster that lets you bump up the line pressure overall.

 

[williamb82]

In a 340 there's an internal adjuster that lets you bump up the line pressure overall.

pics of it and how do we adjust? ive never been inside a a340e but am seriouly thinking of swapping a 1uz into my 86 mk2 and if i do ill likely keep it auto and throw a 3.727 rear in and turbo it. i want the trans to hold. lol.

 

[IJ.]

William: Pretty sure there's pics in the big sticky at SF showing it and which way to click it (3 positions from memory)

 

[wiseco7mgt]

i have both a a340 tranny out of a 91 cressida grande and a 88'model a340 out of a ma70turbo supra, and both have copped a fair hammering but dont seem to be giving up anytime soon, although they tend to be a little slushy between shifts.
i made a simple wiring circuit out of one way diodes to give me manual shifts(made shifts much firmer) but i ended up reinstalling the ect and keeping it factory.i used a large pwr oil cooler which worked fairly effectively keeping the heat down.i too would love to see a write up of different mods for different hp goals, hope more knowledgable people contribute to make this a stickied thread....

 

[TurboStreetCar]

Jdub, its not that i dont believe you, i just want to see more cases of it. i want to make sure its a viable weak point and not a fluke.

The whole point of this thread is to see what breaks. If i said what breaks on a stock 7m there would be 100 people saying rod knock and head gasket, all with personal experience. and then it would be known that the head gasket is a weak point and the oiling system needs to be well maintained. i want the same evidence of failure for the tranny.

Adjusting the line pressure regulator is in the sticky on SF.

Im not necessarily looking for pictures, just personal accounts of broken transmissions, more specifically exactly what part breaks.

So far Sprags are the only part, im guessing second gear? When all the torque of the engine at high rpm gets slammed against the second gear one way clutch (sprag) during the 1-2 shift it lets go?

Though you (Jdub) said Sprags, so that would be more then one.

Would you mind elaborating more specificly? (in a non saracstic, just looking to learn tone)

 

[jdub]

Toyota calls them a "One Way Clutch"...there is actually 3 of them. #1 (low), #2 (intemediate) and Overdrive. The ones I've seen break mostly are the #1 and on one occasion the #2...all were on motors putting out HP in the 300-350 range. Have not seen an OD sprag break. I suspect it was due to stress from the shift.

Not a whole lot you can do to upgrade these (that I know of)...cyro treat is about all you can do. My only "guess" is the #1 clutch is more prone to fail due to the stress from 2 planetary gears (prevents them from turning CW when the 2nd clutch pack is functioning).

 

[TurboStreetCar]

Thats strange how they broke on 300-350hp motors while IJ and a few others are past that mark without such issues.

IJ had his tranny built and listed an "uprated intermediate sprag" in the parts list so there must be someone out there making stronger ones.

 

[IJ.]

There are Sprags available with more dogbones in em this was a popular fail point in th400's way back.

 

[jdub]

Could have been wear too...none of these trannys were "built". I've been pushing more HP than that and have not had any problem with the IPT tranny I'm running.

 

[TurboStreetCar]

IJ yea i was gona pm you about the one they put in your tranny, if its available to purchase separate from a rebuild.

Jdub, any idea of the parts that were put in the IPT tranny? i know they said valve body mods and whatnot and something about new sprags but they dont fully specify if there upgraded ones.

 

[jdub]

The only thing John told me was clutch packs and friction. Did work on the accumulators too.

 

[TurboStreetCar]

Jdub: so they didnt change any of the hard parts like sprags or anything? Only thing you did was have the input and output shafts cryo treated?

Anyone else? Might be rebuilding soon so i want to see what i need. Goal of 500hp's eventually so want to build for that level.

 

[jdub]

Yes, the sprags were changed out...Toyota from what I remember. Might want to PM IJ and find out what he used.

 

[Nick M]

Toyota calls them a "One Way Clutch"...there is actually 3 of them. #1 (low), #2 (intemediate) and Overdrive. The ones I've seen break mostly are the #1 and on one occasion the #2...all were on motors putting out HP in the 300-350 range. Have not seen an OD sprag break. I suspect it was due to stress from the shift.

Not a whole lot you can do to upgrade these (that I know of)...cyro treat is about all you can do. My only "guess" is the #1 clutch is more prone to fail due to the stress from 2 planetary gears (prevents them from turning CW when the 2nd clutch pack is functioning).

I am pretty sure the overdrive planetary drives the main planetary unit.

 

[jdub]

Nick - I think the Direct Clutch (C2) connects the input shaft to the front and rear planetary gears...the OD Direct Clutch (C0) connects the OD sun gear and carrier to the input shaft.

http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=AT&P=5