CDL differences. (1 Viewer)

[PHAEDRUS]

Yeah form the plug ends in the dash they read 25. so I got under with one of my truck mechanics and the btton on the dash does nothing. however if you engage teh t case to low he said you can feel the little motor on top moving but still no lights on the dash. now is that motor what engages the cdl or is it part of the low range set up?
Dave

 

[PHAEDRUS]

well still trying on this damn thing.
to bring it up to speed, I replaced the transmission control ecm and have tested the motor on the top of the t case and they both spec out. ecm reads normal now and if I apply 12 volts directly to the motor it engages and disengages. anyone have any thoughts as to other culprits on this one?
Dave

 

[Big_Moose]

Dave

When the CDL motor engages - have you driven the truck to make sure it is actually engaging & not slipping / broken & you just feel the motor activate?

If it is engaging low range / locking, then it would have to be the switch or a relay.

Take out the switch & test it. I don't have the FSM with me, but there has to be a solenoid / relay some where in the circuit that is bad / grounding.

Hope this helps

Joe

 

[PHAEDRUS]

hey joe.
yeah tested it this morning, cdl swithc does nada, swithcing it to low does nada. tried it in drive and reverse on gravel looking for some wheel slip no dice. so does anyone know what the required steps would be to dissasemble a t case? do I need to drop the trans and t case or will the t case unbolt from the trans? jsut curious as to how to chase this thing.
Dave

 

[PHAEDRUS]

ok so I got a little ahead of myself,
well I can bypass all the wirng and put 12 volts (battery)directly to the motor and engage the cdl, took it out and tested it. works fine. so if I have a used ecm for the trans in there wich specs out and the switch as I understand is bypassed by the transfer case going to low gear(tested the swithc and it specs as well) do I just have a bad wiring set? looking for more ideas and wiping the sweat from my brow and hoping I dont need to drop the t case.
Dave

 

[semlin]

Is the dash lighting up now?

If I u/s right you can't engage it either by switch or by shift to low Shifting to low makes the motor make a noise but not engage while the switch does nothing. Jumping power to the motor directly works fine. If so it sounds like this motor needs more juice to engage than your wiring delivers.

Not sure how much of the wiring is common between the switch and the low shift. If common wiring/relays it could be their fault. If not common wires then problems with both suggests a coincidence or more likely something at the motor end may need cleaning, rebuilding / replacing, maybe from nearby heat damaging it. My old vW van automatic had that problem with the starter. It was next to the tranny and on long drives it would heat up and cook the starter armature. It would gradually require more and more juice to turn it over. I installed a relay to bypass the ignition and shorten the wiring to the battery to get more life out of them but eventually they always failed.

Can you measure how much juice is reaching the motor?

 

[PHAEDRUS]

No
thats the weird part of this. the motor was engaging before I putzed around with it but now the motro will not engage in low or with the switch. so the next question is does anyone know wich wires exiting the transmission relay head to the motor? thinking of bypassing the wiring loom to see if it will engage automatically.
Dave

 

[PHAEDRUS]

one more weird one to throw in the mix.
I got frustrated so put the thing back together and figured I would play with it next week. drove about 15 miles at highway and less speeds to look at a cruiser for simon. got out drove the other truck and went to get back in and go when the cdl light came on. its definitely engaged now but will nto disengage now. tried shifting form high to low, tired going front and back, front and back with mild turns. still on and still engaged. so I figure drive it back to the shop and look at it again. tried to disengage again, back anf fwd, no dice still locked up. so I solved one problem but now I have a different one. any thoughts out there?
Dave

 

[PHAEDRUS]

well in the interest of continuity,
I disconnected the power form the cdl motor and bypassed it with a battery. it made a sharp metallic sound and retracted. it is disengaged now but will nto re engage now. sounds like I have some fun issues to deal with now. oh well drive it over the weekend and will report back as to how its doin.
Dave

 

[e9999]

still puzzled by this 25V thing. If this is a one battery rig with a single 12V battery and 12 V system, you can't have more than 12 V unless there is a voltage converter someplace jacking it up, which would be odd.
But then, what do I know...?
E

 

[landtoy80]

You can drop the t-case without dropping the tranny.
If you do, get the t-case and tranny seal and replace them at that time.

I have my old t-case and can test the motor on it if needed. Just let me know.

 

[PHAEDRUS]

thanks kurt I thought you had dissassembled your t case but could not remember. apparently the cdl motor is the same on 91-97 but on 93 up there is the viscous coupler and on 91 and 92s there is a fork wch locks the spider gears. will tear it apart on monday hopefully and see what gives.
Dave