2000 Ranger tranny problem

[TexasTurkey]

I have a 2000 Ranger 4-cylinder automatic that drops out of OD almost every time I let off the throttle the slightest amount--the transmission was rebuilt about 30,000 miles ago and was never 100% but it worked so I kept driving--I could tell it had some type of OD problem but only slightly until the speed sensor went out and caused a rash of problems--I replaced it and my overdrive came back to life--it worked a little while and slowly started go away again--at first it often just seemed not to ever go into 4th (I have no tach so I just had to listen to the engine) and then it started to drop out of OD when I had to slow on the freeway or let off going down a hill--now every time I slow in the least it drops out of 4th and I usually have to completely let off the throttle and coast down to about 50 mph to get it to go back into gear and then I can go as long as I don't let up --I remember reading on some forum about problems with the valve body gasket but I can't seem to find that thread anymore but it seemed to be a very common problem--also I read here about the 4 different lengths of bolts in the valve body and is there some where to see a chart of bolt positions to see if my rebuilder got some in the wrong positions

 

[imp]

Do you believe the trans. is dropping out of O/D gear because the tachometer needle drops down? The way these transmissions work is that the LAST thing to engage after reaching O/D gear, is the torque converter clutch (TCC). Ford programs their PCM to DISENGAGE THE TCC whenever the gas pedal is released, no matter what vehicle speed or condition of travel. I suspect you are seeing or feeling what seems to be a downshift out of 4th. gear, but is really the TCC disengaging. imp

 

[TexasTurkey]

I do not have a tach in this truck--the transmission drops out of gear and I can race the engine repeatedly--I have to let it coast and completely let off the gas and let the engine idle before it will go back into gear--it gets worse if I get above 65 especially if the engine temp is at full running temp--this is a problem if you are in heavy traffic in San Antonio and you have to slow a little because someone in front slows down but you have to lose 5 or 10 miles per hour to get the tranny to go into gear

 

[imp]

I do not have a tach in this truck--the transmission drops out of gear and I can race the engine repeatedly--I have to let it coast and completely let off the gas and let the engine idle before it will go back into gear--it gets worse if I get above 65 especially if the engine temp is at full running temp--this is a problem if you are in heavy traffic in San Antonio and you have to slow a little because someone in front slows down but you have to lose 5 or 10 miles per hour to get the tranny to go into gear

OK, that kills my idea, sorry. It was not clear to me that the engine speed raced upwards, as though slipping occurring. imp.

Edit: JK080 : HELP!

 

[TexasTurkey]

It seems to be completely out of gear like it lost all pressure or just shifted to neutral--it's not slipping --it's like you pushed in the clutch and raced the engine--but there's no clunk like it suddenly catches--I have to let the engine rpm go to an idle state and then the gear is there and pulls normally when I give it gas--it's like any reduction in pulling pressure allows it to shift to neutral--if I crest a small hill and let up on the throttle ever so slightly it goes to neutral(I live in the Texas hill country)
I wondered if possibly there could be a pressure leak somewhere in the valve-body that let's some check ball move with a very small pressure change?

 

[JK080]

Thats not a common complaint that I am familiar with on this transmission.

This could be electrical, obviously checking codes is something to look at but also watching the computer control the transmission. You would want to check all the components that the computer uses to determine how to work the transmission, like the TPS, VSS, MLPS, etc.

This doesn't fit the valve body gasket problem or misplaced bolts causing problems. If the problem is with the transmission, you might want to start with checking the manual linkage to be sure its all the way into drive and or watching the line pressure. Pull the pan to check for debris, if its trashed your done, it needs to come out.

 

[TexasTurkey]

Thank you for the info--The "tps" is the throttle speed sensor?--It acts like any letting off of the throttle at speed causes it to either shift out of gear or have some pressure change so I'll check the tps carefully--I had the speed sensor on the rear end go out and cause shifting and other problems --I had no idea it controlled so much---O'reilly gave me the wrong year sensor which looked identical to the correct one and only getting a new parts person to check the number found the problem--at that juncture The tranny regained OD which lasted a couple months and the gear dropping started slowly and got worse slowly so that now it occurs with any coasting or throttle lifting above 50 mph--just finished drying-in my new shop--no door yet--but I built-in a 4-post lift--so I can get under vehicles now(50 years of construction makes getting up off the cement hard)--I am going to build and re-build old trucks--I will be getting a tall transmission jack Monday as I have to put a clutch in my nephews pick-up and figure to be changing trannies in my creations as time goes on and will attempt re-builds--I will look at the electrical junction on the underside near the rear of the trans and the tps trying to check the voltages and the connection at the vss on the rear-end and then I'll change the fluid and look for gasket parts--I also bought one of those ELM237 modules to try and get tranny codes myself but it's too far from my network and the tablet needed to connect to the elm and store codes is smarter than me

 

[TexasTurkey]

I finally got my ELM327 to function and got 2 codes P1756 and P1761 which say I have "internal Hydraulic Failure" on solenoids B &C but there are 4 identical solenoids and I can't tell them apart--I can test them electrically and maybe I can hear them click but I don't have an air fixture to see which actually shift on and off--does anyone know if you can remove them without removing the valve body--I would like to know what is bad before I re-do the transmission