Engine/Transmission (1994 - 1998) 1st gear and OD lost...temporarily?

[EGILLILAND]

So I spent the afternoon replacing my fuel shutoff solenoid and starter contacts/plunger (Larry B's) to correct some starting problems. Starting problems fixed and go for a test drive.



I want to goose the truck to make sure the linkage is happy and everything is making power. I accelerate w/the gear selector in 2nd. As soon as the truck shifts to second I lock up the torque converter (w/my mystery switch), TC locks, truck continues to accelerate sharply, then I shift to third manually.



This is where things get wierd. The first thing I notice is the torque converter unlock, the acceleration goes way down and the truck never shifts to OD.



I stop. Pull out again. What I have is no first gear, second gear only starts, auto shifts to 3rd, but no OD and no lockup, either w/the mystery switch or letting the transmission lock things up.



This sounds like some kind of a "limp mode" but I'm not sure.



I get near the house and try something. Totally shut off everything, count to 5, start up the motor again. Lo and behold all is working again. I went straight home, checked fluid levels (they're good), and head to the TD forums.



Do I have some impending failure about to attack me? Or did my zealous use of the mystery switch just confuse things for a moment? This has never happend in 2. 5 years w/this transmission/mystery switch configuration.



Thanks ahead of time for the inputs fellas..... any avoided breakdowns would be awesome.



Cheers,



Gill

 

[biggy238]

Mine does this when it loses 14 volts... Hydraulic 1st and 2nd (or sometimes just slip)

intermittant third or OD and no lockup.



The solenoids in the trans need 12+ volts to operate. .



Maybe something is loosely connected or shorted after your work?

 

[EGILLILAND]

Interesting... could be it. When I pulled out the intake heater could have been in the midst of one of it's last cycles... that would do it w/the voltages.



I'll check the wiring bundles today as well.



Thanks.

 

[biggy238]

Well. . Thats even better because it is specifically my grid heaters that causes mine to function like it does.



The thing with them however, they are supposed to shut off at 20mph... so even if you are running low on voltage, it should come up to operating level voltage just as soon as you break 20mph. It will also shift after that point if they are the cause. .



Ultimately, still... I think the voltage is your cuplprit.

 

[JRosengrant]

I Had Mine Doing The Same Thing Recently. The Error Codes Said The Solenoids Were Bad, Changed Them And It Didnt Work. Sent The Truck To A Dealer With A Good Diesel Mechanic. Turned Out To Be The Computer. Good Luck With It.