42re problem again
 

hi all.

so i changed both governor in my 42re ( selenoid and sensor ).
new atf+4 fluid
it didnt fix anything.
i've searched all over the net but havent found anything like that.

so when cold , it all work like brand new. even the overdrive.
when hot , the overdrive goes off and is REVERSED.
i mean when the od off light is on , the rpm is lower than when it is off. it's a difference of about 200-400 rpm.
at 90 km/h the rpm is around 3k when hot so yeah absolutly no overdrive at all.
also when hot , sometime i have no 1st gear. it start in 2rd gear, not 3 like others.
no slipping at all, shift correctly from 1 to 3, downshift correctly too.

a trans shop , far from me , said he is 100% sure a plate ( not the one holding governors ) is not torqued right so it cause a low pressure.
another shop said it's not possible.

very low on budget right now.

year, engine?
any codes setting?
when hot you lose overdrive and first gear?

1999 v6 3.9 magnum

known codes before i store it
( info from 98 dak and 00 durango FSM , they'r the samecodes )
P1762
display
Governor Press Sen Offset Volts Too Lo or High
description
Sensor input greater or less than calibration for 3 consecutive Neutral/Park occurances.

P0740
display
Torq Conv Clu, No RPM Drop At Lockup
description
Relationship between engine speed and vehicle speed indicates no torque converter clutch engagement (auto. trans. only).

when hot , i always lose overdrive , and sometime lose 1st.
and when hot , o/d switch is always REVERSED. its on when off and off when on.

P0740 come randomly like once a week when hot
P1762 come instantly after starting the engine. even right after a reset. cold and hot.

TCC will get you about a 200 RPM drop, O/D is significantly greater. You will still have TCC when O/D is disabled.

Is the trans temp light coming on in the dash? (does the bulb test when you start the truck?)

yes the lamp work but never lighted up apart from the bulb test and cluster self-test.

But no other trans codes..... Wonder if the PCM is getting confusing data from the trans..... One would think it would whine about that.....

Wonder if you got the wrong parts...... things changed between 99 and 00.....

i know. i ordered a kit that was for 2000 but labeled for 98-99. bought another one for 98-99 and perfect fit.

Might be a short in the wring for the O/D switch...... that would explain a little bit.

so if i understand , the lock-up work (wich is changing the rpm) , but not the overdrive. right ?
when cold , everything work perfect like brand new. overdrive switch work as it should , shift properly and always have 1st.
things get bad only when it's hot.

i guess i changed both governor for nothing as it sound like its THIS part (tcc) causing the problems. i didnt change this one as told by transmission shops.

I would like to know if the PCM is whining about O/D not shifting..... since it doesn't appear to be, it makes ya wonder why..... Under normal circumstances, you should hit o/d about 45 mph or so. If the PCM commands it, but, doesn't see the expected RPM drop, it should have something to say about that...... Why it doesn't, is an interesting question.

It IS whining about TCC though......

Take the truck out on a lonely road, that you can actually drive 55. Would be best if you could start when cold..... See what the trans does when it is working properly. Count the shifts, watch the tach. (and the road.....) Try it with O/D on, and also off. See what things look like.