Automatic transmission slips out of lockup

[Wuppy]

97 Tracker 4 door 4x4 1.6L 16Valve Auto trans w/OD

My transmission will go into OD then reduce a engine RPM further 3 or 400 RPM when the torque converter locks.

Recently, the transmission would go into OD then lock up but come back out of lock up then lock up again as soon as it was under very little or no load, like when driving on a flat non hilly area. If it was under load or coasting it would seem to stay locked.

It has got worse over the last few days though, now it goes into OD then just shudders with each pulse lasting about 1 second. Putting the transmission into "power" mode will help a little but at highway speeds, it seems to have a hard time staying in OD.

It is going into the transmission shop tomorrow (Wednesday). That was as soon as the guy could get it in to work on it. I am guessing the cause is a warn out torque converter or a cracked valve body?

Any other ideas?

[kick-fix]

huge list. 4speed automatic.

even a false , IN 4wd ,will do that.
low pump pressure.

one way to find out is to be sure that the TCC is dropping in the tranny

you need to monitor the TCC command line from the TCM (BCM).
tranny puter.
if the TCM is still commanding (12vdc out) to the tranny , then the problem is the TCM is deciding to drop it.
but then that begs why?


the TCM has many many inputs and if any are wrong then TCC drops.

the TCM monitors, at least, Load (vacuum) , Kick down (DEMAND) and tail speed (vss tach).
not to mention gear selector position. and throttle angle.

but key is the monitor the TCC drive out of the BRAIN.

if TCC is holding then the Tranny is messing up.

how is that. TCC 1a.
PS:

some cars ,many you need to plug in OBD2 scan tool and pull the tranny fail codes 4speed.


PS: OD lamp flashing warns of TCM faults.
if you need the tcc lock up chart with speed and throttle valve rules .
at low 10% TPS angles ,TCC happens at 30mph. ( and faster)
at 20% that moves to 38 mph.
at 30% 45 mph
at 40% its 48mph.

above 40% its total drop out , by the graph.

if od flashes i do have the flash code method of retrieving the errors.
FSM page 71-10a-14 (refr)


btw: the TCC command line on your TCM is pin 12, and is the Gren/yell wire and has NO RELY the new TCC has its own high power driver transistor,relays are for squids.

hahehehehe

[kick-fix]

if you have 3sp, well , dang ,most of above is wrong.
but , the monitor the TCC from ECU to TRANNY with a meter.

TCC RELAY white wire is the test point.


im no expert on any slushpumps, (took the school long ago) but do know the electronics.
that is my bailiwick.

we can findout, what major component it is ,
tranny or TCM or inputs to latter.
for sure.

[Wuppy]

Looks like the torque converter needs to be replaced. The transmission shop has it apart... They have located one and have it on order. I hope they have it finished soon. In the mean time I am driving a friend's spare ride - 1986 Grand Marquis. I am told I look like a pimp.

[kick-fix]

sorry for you tcc loss, bummer.
was hoping for chaffed wire......