47rh problems

Macktruckdriver

New member
Joined
Feb 25, 2008
Messages
4,358
Ok Im figuring my tranny is done for but heres what it did. Drove it to work and back then to a buddies house. When I left to go home it wont shift to 4th and lock up. If I shut the OD off it lock like always in third but turn the OD back on it run it up and it sometimes shifts to 4th I think but will not lock up. Any Ideas. Im getting ready to pull it in on my lunch break at work to look it over. Tranny fluid is full also. Could it be one of the wires or is my converter or tranny shot.
 
Is the fluid dark or does it smell burnt?


If not, it sounds more like a throttle position sensor (APPS) problem. 1st thru 3rd are hydraulically controlled on the 47rh, OD and lockup are electrically controlled by the PCM. The PCM is controlled by the throttle position sensor formally known as the APPS.

If you want to be cheap, you could hard wire a grounded toggle switch to the front wire on the flat 3-prong plug on the driver's side of the tranny. When you want OD, flip the switch and it will shift into overdrive as long as the tranny is in 3rd gear. If you flip it in 2nd gear, nothing will happen till you reach enough speed to make the tranny shift to 3rd then it will immediately go into OD.

While you're under the truck, you might as well wire up a grounded toggle switch to the rear wire on that same 3-prong plug so you can command torque converter lock-up whenever you want it. When you flip the switch, as long as the tranny is in 2nd gear or higher, it will lock up. If you flip the switch in 1st gear, nothing will happen till it shifts to 2nd gear and then it will immediately lock the torque converter.
 
If you want to be cheap, you could hard wire a grounded toggle switch to the front wire on the flat 3-prong plug on the driver's side of the tranny. When you want OD, flip the switch and it will shift into overdrive as long as the tranny is in 3rd gear. If you flip it in 2nd gear, nothing will happen till you reach enough speed to make the tranny shift to 3rd then it will immediately go into OD.

I normally suggest trying something like this as a preliminary troubleshooting tactic to see if the trans is ok or not. If OD still works by manually engaging it then you know you have issues outside of the trans. Another suggestion I normally make is to put a light on the OD and TCC wires to see if the PCM is grounding the pins to engage OD and lockup.

It's up to you whether you just decide to leave the switch on it as a "fix" or not, assuming that you find that to be the issue.
 
what is front and what is back it sits on the tranny at an angle . Are you saying the one closes to the housing as back and the one more to the out side is front. So left is front right is back. I have 2 new tps at home and a spare plug for the 47rh so I can make a manual plug for now.
 
There are 2 plugs on the trans. The one that goes in from the side is not the plug you need. The one you are looking for is rectangular shaped with 3 wires going in it. I believe the wires are orange, light green, and brown. That plug goes straight down into the VB area by the shift linkage.
 
The orange with white tracer is for torque converter lock-up, the brown is for OD, and green center wire is 5v power lead for OD & Lock-up solenoids in the tranny.

Obviously, you need to peel the cover off the wire harness to see the wire colors. If I were you, I'd tap the wires with a T-Tap, you don't need to cut the wires for the lockup and OD to work, you simply need to ground the wires through a toggle switch.
 
Back
Top