1999 F150 with 77,000 miles, 4.2L 6-cylinder. When I bought it 4 weeks ago, the gearshift pointer was a full space off; when the truck is in Park, the pointer says "R". Then, 2 weeks later, the tranny starts slipping from 2nd to 3rd with Overdrive on. When the OD is off, it no longer slips, but there is sometimes a hard shift. Spent hours looking at videos and websites...kinda think both problems might be related to the Digital Transmission Range Sensor. The fluid is new and red, not burnt. When driving on the flat the slipping is neglible, but if going up a grade, I have to back off the juice at the shift point so the engine doesn't red line between gears. Don't have any testing gear, but ok with a wrench.

 

Not yet ready to say the trans is in trouble until you get under the dash and look at two items.
1 Down at the firewall area, the shift rod has an arm held on by 2 bolts.
This arm moves the cable to the transmission selector.
Are they tight?
2 Up behind the dash cluster is a plastic part that moves the window indicator on the front.
Is it broken?
Only after you check these out is it time to blame the trans for having a shift issue.
Good luck.

 

Thanks, I'll check those tomorrow. I know the pointer is attached to a cable that has a gear like adjustment on it, I tried that, didn't seem to move the pointer either direction. But I will try again. thanks again, I will report back.

 

You are correct on the white clip hold the adjusting cable. It's broken. When I slide it down into place, the pointer shifts from D to N. Open for ideas on how to cheaply repair it. Is just that clip replaceable?

As to the 2 bolts holding down the shift rod cable, there are none. It looks like the shift rod curls down from the area above and into a rubber boot (see photo).


I can manually push the cable in about 3/8" then it springs back. The cable is also held against the firewall by a push on clip over a threaded stud. Comes off easy enough and presses back in place. Open for ideas here too. While under the car days ago, I took off the shift lever from the DTR (see photo). I noted then that the cable had about 1 position of play in it.

 

The shift indicator part is available from a dealer.
It's held in place by one screw.
Good luck.

 

I guess I'm ready to hear the bad news. Tranny continues to slip from 2-3 with the O/D on, and doesn't slip with the O/D off. Ideas, anything to check?

 

I haven't had that exact problem but I have had issues with the 2-3 shift and some of the troubles I have had was because the end plug for the 2-3 shift valve in the valve body was loose and leaking. I used a pipe cutter to groove the plug to seal it into its bore. This has fixed a few 2-3 shift problem in the past, one in particular did not have 3rd on the road test but had it on the lift. I seal this and a few others during every rebuild now.

Sonnax makes a kit to help with this issue, it may be worth a try for you.

Sonnax - Aftermarket replacement transmission, torque converter, and high performance automotive parts

 

I have a BIG problem understanding how the OD switch affects your 2 to 3 upshifting.
Why:
The OD switch electrically signals the PCM through dedicated two lead wires to the PCM to lock out the overdrive function.
The OD function can only work in the shift selector position circle D 'over 45 mph' and light throttle.
You can't be seeing any effects the way you describe it because it does not work that way or even close to it unless some one has done something very funky.
Good luck..