transmission solenoid

[LMP]

I do not see any factual relation between the 85 ohms and your 1/2 problem, indeed. There is still some mystery there....since it has happened on both transmissions...could we imagine the problem is external....

ABout the diode: it is part of the solenoid circuit. THis is known as a "free wheeling diode" and it allows inductive current to die out, when opening the circuit, whithout generating a high voltage spike that can damage windings.

diode measurement: the battery included in you multimeter is used for reistance as well as diode measurement. The result is just shown differently. In the resistance scale, current circulated through the "resistance", whatever it is, is used to make a calculation using the internal voltage and displayed in "ohms". ON the diode scale, the current is circulated through the diode and the voltage across the diode is measured and displayed as such. Diode drop is always near to 0.6 volt in the "forward" direction, and no current will flow in the reverse direction, thus leaving the full voltage of the internal battery as the measurement, then shown as "infinite" or "overscale" on the diode display.....

[wagonman76]

I had problems with TCC shudder on my 92 Trans Sport with 4T60E. I also had problems with the TCC and OD dropping out after sitting in traffic, or pulling a trailer. I took resistance readings and most solenoids were just a hint over spec, but one was like 118k ohms. So I bought a solenoid kit and tore into the side pan. Just for kicks I measured the solenoids themselves, and every one was perfect. So I suspected the harness. I cleaned it really good. Also the solenoid connectors seem like a really hokey design. It seems they cant get tight no matter what, and it looks like they can heat up and expand and lose connection. I tightened them the best I could till I got good readings outside the trans. The problem is solved for the most part now. No more shudder. But when pulling a heavy trailer up big hills, it heats up just enough to kick out OD and the TCC once in a while. When I get a chance to go in the side pan again, Im going to cut out those stupid connectors and solder and heat shrink the connections.

[nicke66]

Originally Posted by LMP

There is still some mystery there....since it has happened on both transmissions...could we imagine the problem is external....

Paul, correct me if I am wrong, but didn´t the first transmission stop working at all, but you have 1st and 2nd gear with the rebuilt transmission?

[ESP89]

LMP, I have a problem with my 96 transport trans, when cool it will go right into gear and stay and operate fine, but when it warms up it will not go into any gear at all including reverse. I hear a sound almost like a buzzing like squeal for about 2 seconds when it is warm and then it wont engage. after it sits for a while it will drive again.any idea what this may be, maybe a solenoid or modulator, or maybe the valve body ?

[LMP]

Originally Posted by nicke66

Paul, correct me if I am wrong, but didn´t the first transmission stop working at all, but you have 1st and 2nd gear with the rebuilt transmission?

Yeah..hopefully I was wrong here in my last remark..I had read Viala's last post a little bit fast and got the impression he described same trouble....

[LMP]

Originally Posted by ESP89

...transport trans, when cool, will go right into gear and stay and operate fine, but when it warms up it will not go into any gear ... after it sits for a while it will drive again

I would hope the explanation would be debris that fall to the bttom and then collect on the strainer after a few minutes of operation and block oil supply to pump...that would be easy and solved, at least temporarily, with a new strainer and change of fluid....but I do not expect this simple explanation would be anough. IN any case, dropping the transmission pan is easy and inexpensive ..though a dirty job...and will allow to peek an eye . IN fact I had extended the life of a former transmission with this simple change..but had to go for the real problem later.
HOnestly, any seal that starts leaking when warm can be an explanation...so it is a little hard to do a prediction worth more than the words. In fact this problem has been mentioned on this forum a few times, but either the outcome was not revealed, or a full rebuild was done, the precise cause not being identified...Some other foruim member might come with a better clue...