2000 f550 7.3 4x4 with pto. Junk truck project with many problems I'm slowly working through.

Truck had no forward drive so I swapped a good forward clutch from a E4OD to restore forward drive. While apart, all the other clutch packs/pistons looked ok and seemed to function. I could get them to move and "thunk" when I blew some air into the appropriate valve body orifices. The valve bodies had extra check ***** in them so I left those out upon reassembly. (one big ball and one small ball) The valves themselves seemed to slide in their bores normally.

When truck is shifted into Drive, it starts out in 1st and pulls normally. When it tries to shift to second, it pulls for about a second and then a serious drag sets in, slowing the engine and truck. Gear selector in "1" gives me first gear and shifting to "2" gives me a normal second gear. If I then shift to drive, I get the dragging scenario. The speedo works but the odometer doesn't. I don't have my brake lights wired up.

I unplugged the connector at the firewall and ohm tested the pins that lead to the shift solenoids and they were in the normal range in the manual. I think this eliminates a solenoid or wiring problem.

I have car gauge pro and I don't think I have any error codes but maybe I'm not looking in the right menu for them.

My pto function works and I can drive the truck around the farm in first and second but I would like to figure this out. I'm not sure of what normal 4r100 behavior is but I suspect I might have put it back together wrong and the transmission is trying to shift into second and reverse at the same time. Maybe the torque converter is doing something weird. Maybe those check ***** needed to be in there but all the videos and manual pages I see say otherwise. I haven't measured any line pressures. My OD light works and isn't flashing while this is going on. It does light up when I turn on the pto, though.

 

If it were the torque converter it would always have the problem. The torque converter does not know what gear the transmission is in.

I suspect you do need those check *****. I do not have a chart for where they belong. You need a chart for a 2000 with PTO to make sure you have them correctly installed.

 

Time flies and I'm now just revisiting this. I got the ASTM info that states the PTO checkballs are the same configuration as nonPTO. The ASTM also lists a chart of the solenoid combinations required to shift through the gears. I think my symptoms are explained by "Solenoid 1 always on"

The result of this is that the trans stays in 2nd gear when the PCM calls for 3rd and then shifts into first when the PCM calls for fourth. (i think)

What are the possible causes for Solenoid 1 always on?

I also have a Po500 code for vehicle speed sensor but my speedo works and Car Gauge PRo App shows vehicle speed while I drive it...

 

Solenoid 1 always on can be caused by a mechanically stuck solenoid or a short to ground in the wire to the solenoid.