Keeps popping out of over drive after 40mph

[ParanoidSVT]

Hey gang, I’ve been bringing my grandfathers 2004 Ranger. 3.0, 2wd back to life.

it has been totally fine for him and I over the years, until about a week ago… I’ve developed alittle issue

it seems like once I go above 40mph and 2k rpm the truck pops out of over drive, jumps up to 2400rpm, then immediately shifts back into over drive bringing it down to 2k rpm.. then pops back out and repeats… if I bring the speed down to 35/38mph and 1800rpm she’ll be fine all day long

if I also hit a on ramp to the high way.. it will shift normal all the way up to 65mph… I ran to Boston (45 miles straight) with no issue at all.. BUT the second I go below 60mph… she begins popping in and out… bring her up to 65mph.. and I drove all the way home from Boston fine..

shifts aren’t violent like it’s low on fluid. I even checked and the fluid is a clean color and right where it needs to be on the dip stick

I’ve done some googling and really haven’t found an answer… I’ve seen things like TPS sensor and transmission servo..

Another thing I’d like to throw in is, no CEL, no blinking lights.. but my over drive button and light doesn’t work… and I don’t believe it ever has…

any advice is greatly appreciated…

 

[cbxer55]

The OD light is just a standard light bulb, they burn out. Ask me how I know this!!

I had a 2007 4.0 auto Mustang for awhile. It had lots of transmission issues, that were all traceable to the torque converter being bad. Friend of mine who does transmissions replaced it and the problem went away.

Problem with the OD light not working, is it will tell you if you have transmission issues. If the OD light blinks, it's telling you there is something wrong. So, yours not working could be hiding the fact something is wrong.

Also, when the OD light is blinking, you turn the vehicle off and it goes away until the problem presents itself again. My stang, it would start blinking. I'd pull over, shut it off, restart it and the ight was gone. For ten minutes or so, then it would return. You have to take it and get the code read while the light is blinking. Drive it to a place that read codes, like Auto Zone, and leave it running until they check it.

Even though your light isn't working, the codes may still be there. Transmission codes are P07... codes. My friend Rick, at Ace Transmission in Midwest City OK, has a special code reader just for transmission codes.

 

[cbxer55]

BTW, the problem with my torque converter was the lock-up converter wasn't locking. The code P0734, I think, lockup converter locked off. And that caused lots of odd problems like hunting between drive and overdrive. When it was cold, it didn't happen, because the converter doesn't lockup until operating temperature is reached. And only above a certain rpm range. Below that it's unlocked and when cold it's unlocked.

The Mustangs five speed auto is just basically the same as the four speed the Ranger has, with an extra gear. 4R44 versus 5R55.

 

[Uncle Gump]

Ya know... most automatics have that "sweet spot" where if you hold the pedal steady... the torque converter teeters between locking up and disengaged. If it doesn't do it below that speed... try going 5 mph faster. Dies it still do it then?