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Auto box specialists - Help!


Swampy442

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Have a problem that Im tearing my hair out over.

 

Car - Toyota Crown

Engine - 1JZ-FSE

Gearbox - A340E

 

Problem - When cold it operates as normal, once warm, as you coast to a stop the box doesn't kick down, leading to juddering and vibration until the box is forced to kick down. It changes up gears without issue, kicks down without issue whilst on the move, can select all gears manually, OD operates as normal, no crap in the fluid, no noises or grumbles.

The only error codes I came up with were throttle sensor, which I replaced with a brand new genuine item, now there are no codes at all.

Normally Id point to the No1 speed sensor but I replaced that with a known working one and no difference.

Flushed the box out and replaced the trans fluid with 70 quids worth of oil, no difference. There are no speed convertors fitted either.

 

So Ive covered all bases that I know of, anybody know of something Im missing?

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Not sure it's the same issue but my box wouldn't come down gears and rolled into junction in 3rd etc and was trying to pull away in 2nd sometimes 3rd then after you pulled out it hunted for 1st gear. Went up Gears fine but struggled to come down. The idle was high also about 1200rpm. Turned out two vac pipes had come off on the plenum side near the throttle body. AFR's were a bit off also. Connected the vac pipes and it's all good now.

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No idea what the cause might be, Craig, but my advice would be to fit a Soarer TT engine and box. :)

 

Since it's an A340, what happens if you unplug the electrics from the box? That should allow you to select 1, 3, 4 (O/D) with the lever in 1, 2, D.

 

Juddering does seem as if it might be the TC lock-up clutch. It should be disengaged below about 35mph. Does it happen if you change down to 1 on the lever?

 

 

http://www.autoshop101.com/techarticles/technicalarticles.html

 

Technical Articles

Toyota Series - Automatic Transmissions

AT01 Fundamentals of Automatic Transmissions.pdf 144KB

AT02 Torque Converter.pdf 478KB

AT03 Simpson Planetary Gear Unit.pdf 380KB

AT04 Gear Selection and Function.pdf 20KB

AT05 Power Flow.pdf 1211KB

AT06 Automatic Transmission Fluid.pdf 27KB

AT07 Transmission Oil Pump.pdf 136KB

AT08 Valve Body Circuits.pdf 963KB

AT09 A340H Transfer.pdf 60KB

AT10 Electrical Control.pdf 308KB

AT11 Transmission Check, Adjustments and Diagnosis.pdf 170KB

AT12 Shift Lock System.pdf 186KB

AT13 Appendix.pdf 1290KB

 

Technical Articles

Toyota Series - Automatic Transmissions

AT21 Automatic Transmission Basics.pdf 1723KB

AT22 U-Series Transaxle.pdf 947KB

AT23 Valve Body Circuits.pdf 610KB

AT24 Electronic Control System.Pdf 860KB

AT25 Diagnostic Procedures.pdf 621KB

AT26 Diagnostic Tester.pdf 485KB

AT27 Remanufactured Transmission.pdf 186KB

AT28 Appendix.pdf 339KB

Edited by garethr (see edit history)
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