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Matt
Matt, Engineer
Category: Transmissions
Satisfied Customers: 20580
Experience:  Mechanical Engineer BEng Hons22 years experience in car engine industry, 10 years in formula 1
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Automatic Transmission F4A33 3000GT SL 1998 DOHC, Shift into

Customer Question

Automatic Transmission F4A33 3000GT SL 1998 DOHC, Shift into 2nd gears by mistake, when up shift from 3rd to 4th. Before it happen, the transmission acting like a delay shift (RPM rev much higher but not shift into 4th gear, then it eventually make the shift with a bang, like get knock down to or get shift into 2nd gears instead of 4th gear). Something engine light will come on, but most of the time no. ECU code P1750. TCU code 54. Only happen one time per day. Usually happen right at ~5 minutes mark during the 1st drive of the day. After it happen, car will drive fine the rest of the day, event after parked for a few hours.
** Repair History: Engine over heat due to radiator leak. But notice engine valve cover leak result from the engine over heat incident. New radiator was installed. Transmission oil changed and filter changed, but fluid was over filled. Found out a week later, and rained out 2 quarts of fluid (Over rained). Transmission running at low transmission fluid about (1.5 quart lower the normal) for over (check fluid lever with wrong way). Used Castrol Import Multi Car ATF, not Mitsubishi OEM Fluid. Then just flushed the transmission with Volve SPIII compatible 3 weeks ago, no help.
Submitted: 1 year ago.
Category: Transmissions
Customer: replied 1 year ago.
The transmission was working flowlessly before the overheat incident happen 2 years ago. I believe due to I under filled the transmission fluid during that initail filter and fluid change, which result in 4th gear failed (fluid pressure too low to engage 4th gear)Not knowing the fluid low issues, I rebuilded the end clutch with a End Clutch Kit from Alto about 1 month ago. Then during that rebuild I found out that I had been checking the fluid lever wrong. So, I'm not sure if my new problem resulting from my End Cluctch rebuilded not done right, or the inital problem never fixed. Before the end clutch rebuild, I can never get on 4th gear, it always ending with a bang then go into limp mode.
Customer: replied 1 year ago.
The transmission was working flowlessly before the overheat incident happen 2 years ago.
I referring to Engine overheat, not transmission. I have not aware of transmission over heat. Fluid was fine, pink and clean. No sign of metal partical or clutch friction material in filter.
Customer: replied 1 year ago.
Correction:
Transmission running at low transmission fluid about (1.5 quart lower the normal) for over 1 year (check fluid lever with wrong way).
Customer: replied 1 year ago.
Correction:
Transmission was running at low transmission fluid about (1.5 quart lower then normal level) for over 1 year. (I checked fluid lever wrong, at park instead of at neutral).
Expert:  Matt replied 1 year ago.

Hello

code 54 = 4th gear not synced

so this is likely to be a sticking shift solenoid

I'd suggest doing a another fluid change as usually you have to do this twice anyway to refresh whats in the torque convertor and then see how you go from there

Customer: replied 1 year ago.
I did a ATF changed 1 month ago. Then follow up with a new filter change and fluid flushed 2 weeks ago. I referring to flushed, not just drained and refilled.
Customer: replied 1 year ago.
Are you referring to sticky valve or sticky solenoid? You also mention TC. What wrong with the TC?I was suspecting something get stuck inside the valve body, may be a sand get drop into the refill tube when I refill the AFT. But how all this (including the sticky solenoid) affect my symptom (only happen with OD switch on, and 1 time a day)?I followed this video: (to fix my End Clutch, is anything that I could had did wrong in these procedure that can result in my symptom? The old parts in the end clutch look good that why I though the original problems were just fluid low, not the end clutch at all.) Can fluid low prevent me from engage into 4th gear due to pressure too low?http://www.google.com/url?url=http://www.youtube.com/watch%3Fv%3D90CR6Zzz1JM&rct=j&frm=1&q=&esrc=s&sa=U&ved=0CBsQtwIwAWoVChMI7Zuf5Nz-xwIVgpiACh2Z0wTa&usg=AFQjCNGHKrf03_QZ6nIyjWijEfio7RFRTA
Customer: replied 1 year ago.
Here is the rewrite of my symptom.
Before the end clutch rebuild: (I thing this is result of low AFT)
When ever climb and steep hill or when the transmission at the timing to up shift to 4th gears, it would slam very hard (feel like hitting a pot hole) and get knocked down to or get shift into 2nd gears instead of 4th gear. Engine rev very high like you put on engine break (50 mph into 2nd gears). I could never got on 4th gears.After the end clutch rebuild, ATF flushed, and fluid lever corrected:
Before it happen, the transmission acting like a delay shift (RPM rev ~300 rpm higher then usual before it hard shift with a bang into 4th gear), whole car jerk very hard. Before it engage into 4th gears, it feel like the gear was at neutral for a few second, the RPM shoot up to 5000 RPM from 3000RPM. After that hard shift, if I turned of the OD switch, it will followed with another hard shift out of the OD Clutch in less the 1 minute. Either way, with or without OD, after that initial hard shift, I will able to drive the car fine the rest of the day.
Expert:  Matt replied 1 year ago.

Hello

thanks for the extra information

as you've already tried flushing it through I'd say the next step is to replace that 4th gear solenoid with a new part

Customer: replied 1 year ago.
If it's solenoid, I suppose to get TCU code 4X. And also why it only have once a day? Normally a failling solenoid would cause problem after hot. This seem like it happen early then drive fine after. Also, I just notice it happen with OD swith turn off too, at the 5th minutes mark, but the delay was short and hard shift also very soft, that I was not notice it before. Or may be it get worse, that now started happen the 3th gears. TCU code now 54, and 53. I suspect it may have to do with the kickdown servo band. I know the kickdown servo can be adjust and a O ring need replaced during adjustment? What is the symptom if my servo were miss aligned due to the hard impact when I drove the car wth low ATF for 1.5 year? Or if the O ring were damage from the engine overheating incident? Or If my band just worn out?
Customer: replied 1 year ago.
If it's solenoid, I suppose to get TCU code 4X. And also why it only happen once a day? Normally a failling solenoid would cause problem after it hot. This happen early then drive fine after 5 minutes. Also, I just noticed it happen with OD switch turned off too, at the 5th minutes mark, but the delay was short and hard shift also very soft, which I was not notice before. Or may be it get worse, that now it started to happen to the 3th gears. TCU code now shown 54 and 53. I suspect it may have to do with the kickdown servo band. I know the kickdown servo can be adjusted and a O ring need to be replaced during adjustment? What is the symptom if my servo were miss aligned due to the hard impact when I drove the car with low ATF for 1.5 year? What is the symptom if O ring were damage from the engine overheating incident?
Expert:  Matt replied 1 year ago.

Hello

if the servo was misaligned then you're quite right in saying it would stick and also create the scenario you describe

so adjusting the servo is worth a try

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