Slipping gears still after tranny swap :S

[shezza]

Hey guys,

I am the owner of a MX-83 Cressida. I was servicing my car which involved a tranny oil change and when I went to test drive it, my gears were all slipping. So it seemed my clutches were gone and I got a second hand box. After finally installing it I took it for a test drive and the same slipping was/is going on...
Is it possible that the problem is not coming from the tranny itself?
Anyone got any ideas?

Cheers

Shai

[Dale]

Was it happening with the first box before you changed the oil in it?

[shezza]

Was it happening with the first box before you changed the oil in it?

Thats the thing... I had the common slight slippage at the start of 2nd gear and that was about it. Then I did the service and changed the oil (with recommended type) and then it all went...
I dunno if this says much, but when I restart the computer I gain the drive gear a bit (which I couldnt get before at all) for about 30 or so seconds and then I lose it again. To see if it was just luck I did it again and I gained it like before... Beats me what it means

[Dale]

What else did you do at the same time as you did the first service, sounds like the problem may be something else that happened at the same time.. no wires got damaged or anything somewhere along the way? (not sure if it's an electronically controlled box though)

Otherwise maybe the fluid level is wrong, or something is wrong with the torque converter.. is it the same torque converter off the old box by any chance?

[shezza]

Well my own fault for having hope. But I got excited when I rememebered that I also changed my radiator on that day. Hoping there was a blockage or something related with it, I bypassed the radiator and joined the pipes. Same shit
I wasnt near any wires on the day and I used the convertor that came with it.
I checked the fluid levels first thing. It was a tad below full so I filled it up. All to no avail :S

[thechuckster]

MX83 = 7MGE & A340E gearbox?

is a different body, but the gearbox is similar ... plenty of reading matter plus some diagnosis charts:
http://www.cygnusx1.net/Supra/Librar...tion=AT&Page=1

[Dale]

Do these have a separate computer in them that controls the auto? (excuse my ignorance on mx83s!)

I guess if you can get hold of one to borrow and plug in it might be worth it to see if the problem still occurs.

Hopefully someone with more knowledge on the subject than me can reply and give you some better advice!

edit - there we go, Charles posted right before me there

[shezza]

That is my tranny. To my knowledge it does not have a individual tranny (although my knowledge is kinda limited )
Thx for that chux.
I pulled a code.
It states "Defective No. 2 speed sensor (In ATM) - severed wire harness or short circuit"
Does it make any sense for the "speed sensor" to be the problem? What is its function anyway?

[thechuckster]

tells the gearbox ECU how fast the output shaft is rotating - without that it wont lockup the torque convertor so it'll feel like the gearbox is slipping. andprobably some other stuff

[Mos]

Defective No2 speed sensor won't be an operationally limiting problem unless you've also lost SP1 (which should spit out its own error code through the check engine light).
SP2 is on the rear of the gearbox, depending on whether you have ABS or not. Non-ABS should be a single wire sensor, ABS will have a 3 wire sensor.

Lack of a speed sensor should not affect the feel of the gear change as it won't change out of first gear electronically (unless for some reason it's changing hydraulically). You can try manually shifting the box using the shifter.

Too much trans fluid can also cause unpredictable operation.

The torque converter lockup should only ever happen on 4th gear at cruise conditions - it will not be active with lower gears selected and definitely will not be active during gear changes.

These boxes don't have anything electronic controlling the line pressure or accumulator pressure, so there shouldn't be anything ECU related provided it's changing gears.
Have you checked/reconnected the kickdown cable during the transmission swap?

Mos.

[shezza]

Defective No2 speed sensor won't be an operationally limiting problem unless you've also lost SP1 (which should spit out its own error code through the check engine light).
SP2 is on the rear of the gearbox, depending on whether you have ABS or not. Non-ABS should be a single wire sensor, ABS will have a 3 wire sensor.

Lack of a speed sensor should not affect the feel of the gear change as it won't change out of first gear electronically (unless for some reason it's changing hydraulically). You can try manually shifting the box using the shifter.

Too much trans fluid can also cause unpredictable operation.

The torque converter lockup should only ever happen on 4th gear at cruise conditions - it will not be active with lower gears selected and definitely will not be active during gear changes.

These boxes don't have anything electronic controlling the line pressure or accumulator pressure, so there shouldn't be anything ECU related provided it's changing gears.
Have you checked/reconnected the kickdown cable during the transmission swap?

Mos.

Is the speed sensor the thing that gives me my speedo reading? If so... the tranny was formerly fitted with a electronic pick up as some cressidas came with a electronic speedo. It was very straight forward to plug my mechanical one on. Didnt seem like an issue...
Another thing I should mention... This tranny has an extra wire coming off of it *with four wires). I have nothing coming off my car to plug it into. I figured it was for something I lack like abs or the electronic speedo so I ignored it.
I did try the manual shifiting as when ur desperate... there isnt much u wouldnt try
I was slightly under full trans oil so I filled it right to full and it changed nothing... so I dont think its the prob. I did reconnect the kickdown cable and it went smoooth as. No problems that I could see or feel.

[Robbos_Toyotas]

how about the kickdown cable, if it is too tight, it can cause the box to hang in gear or slip...

[shezza]

When my car was on the road, I played around with the kickdown cable. I had it at both extremes and it never slipped at either end, so Im thinking not... Plus I adjusted it roughly to the recommended place. Keep the suggestions coming though. Not in the mood to change the tranny again. More the money as opposed to the time.