INTRODUCTION
The A340E we will be discussing came mated to both the 2JZ-GTE (TT Supra and Aristo) and 2JZ-GE(SC300 and Non-Turbo Supra). It also came in the 4runner, Tacoma, and some Jeeps and Volvos. The A340 is different than the A341 which came in SC400s and LS400s, with the short explanation of the differences is that the A341 has a slightly longer 1st gear.
The bellhousings of the TT auto and N/A autos will both bolt up to the 2jz, however on a visual inspection the TT bellhousing is slightly larger to clear the larger TT torque converter.
While I am not sure how similar the A340E from the SC300 is to the A341E in the SC400 I would imagine the link below which is about swapping input shafts. Theoretically though you should be able to swap the input shafts on the two trannies which would allow you to retain your SC300 torque converter, flexplate, and flexplate bolts.
http://www.pirate4x4.com/forum/archi.../t-336619.html
The tailshafts are also different with the n/a tranny having a hole for the driveshaft to slip into and the TT auto having a bolt on flange. Swapping tailshafts is much harder though as you'd need to literally disassemble the entire transmission to swap the tailshafts.
Here is a thread which should give you a general idea of what you'd need to do to swap tailshafts.
http://www.supras.nl/index.php?optio...d=35&Itemid=52
Links
http://www.max-boost.co.uk/max-boost..._DIAGNOSIS.PDF
http://www.autoshop101.com/forms/AT08.pdf
DIFFERENCES
TT Auto
- HP Limit -425-450 w/ a good cooler.
- Valve body has 4 solenoids, the 4th solenoid controls line pressure electronically. This allows smoother shift modulation.
- Has a larger torque converter that is more efficient.
- TT torque converter requires use of a TT flexplate and TT flexplate bolts.
- Driveshaft bolts onto the transmission to a 3 bolt flange.
- Has a different input shaft than the n/a tranny.
- Has more clutch packs than the n/a auto.
- Valve body solenoids activate linearly allowing more precise transmission control.
N/A Auto
- HP Limit : ~325-350 w/ a good cooler
- Transmission line pressure is controlled by a cable and only has 3 solenoids in the valve body.
- Has a slip type tailshaft housing for the driveshaft. Driveshaft slips into the transmission itself.
- Valve body solenoids have an on and off activation.
The biggest problem with the n/a auto's in our cars is the fact that it has an extremely low HP limit.
You can shim the accumulators in the N/A auto which allows for quicker shifts, reducing the amount of time the clutch packs slip and therefore creates less heat allowing for more hp. But the problem with n/a A340's compared to the TT auto is there is a limit to shimming in the fact that it simply doesn't have enough clutch packs to hold much power.
So far, people with n/a auto's don't have many options when it comes to stronger tranny's. BL and many other companies offer rebuilds that allow for a higher hp limit but these services generally cost around 2 grand and can't hold much more than the stock TT auto, which isnt' very much more considering how much it costs. In these services the most notable change is they swap out the clutch packs with raybestos blue plate clutch packs which are stronger.
When you shim the accumulators however, you should may want to consider shimming the 1-2 shift a little less agressively because the next weakness in the tranny after clutch packs is the 2nd gear sprague and hard 1-2 shifts can break it.
The reason swapping a TT auto is complicated is because of the line pressure issue with the valve bodies. Believe it or not, the cable the n/a auto has is NOT a kickdown cable but a cable to control line pressure. The problem with the TT tranny is line pressure is controlled electronically via a solenoid. The solenoid is linearly controlled and allows for more precise line pressure control. So far, the only way to control the TT tranny is with an AEM, however.
A 1500 dollar solution to simple transmission control.
Latent Solutions makes the 'suprastick' tranny controller but it will only work with the n/a valve body, ie: valve bodies with mechanical line pressure.
Pictures
The TT tranny is the bottom tranny and the n/a tranny is the top tranny. Here you can see the differences in the tailshafts and that the two trannies are almost identical internally.
Closeup of an n/a tranny.
Closeup of a TT tranny.
The TT valve body is on the bottom and the N/A valve body is on top. You can tell the TT valve body is much larger and doesnt have the two tubes going into the back part of the tranny. One of these tubes sends fluid to the B3 accumulator while the other one sends fluid to lubricate the tailshaft.
This is a picture of an n/a tranny's clutchpacks.
Here you can see that the TT tranny has more clutchpacks.
All the n/a hardware (valve body, mechanical line pressure cable, and solenoids) bolt right into the TT tranny.
You'll need to swap the wiring harness for the valve body though.
Wiring harness comes out easy, just swap the n/a for the TT one.
The TT tranny has a simple plug where the cable for line pressure goes into the n/a tranny. Simply pull out the plug and swap the cable into the TT tranny.
You also need to swap the gear selectors.
The accumulator on the far right bottom by itself away from the other cluster of 3 accumulators needs to be swapped with the n/a one and springs. When swapping in the n/a valve body you dont need the cap that comes with the TT one.
I plan on however, swapping the valve body from a non-turbo A340 into a TT A340 so I can have the extra clutch packs AND the mechanical line pressure control, so I don't have to go AEM.
More to come!
