95 Ranger transmission problem

My 95 Ranger has a problem that 1 mechanic and 1 transmission specialist has not been able to figure it out. The Ranger is a '95, with 4L V6, and 4WD with automatic transmission. Under certain driving conditions, the transmission seems to go into neutral for no reason, the engine revs up like it has no load and then it goes into gear again. I can make it happen every time by driving up to about 30mph, coasting to about 20mph and then accelerate. The rpm will jump up a bit, the truck decelerates a little then engages into gear again and off we go. This can also happen sometimes if traveling around that speed and going up a slight incline, and perhaps accelerating a little. The most exciting time it does it is at random times when traveling between about 40mph and 55mph. It seems to happen only when cruising on the highway at a steady speed, not during acceleration. Turning off the overdrive does not stop it from happening, but it has never happened while driving in gear position "2" at any time at any speed. I cannot make it happen at will as at the lower speed. When the outside temp is below around

30 degrees F, the problem is practically nonexistant as far as the higher speed phenomenon is concerned. I still does the lower speed thing at any temp though. The transmission was rebuilt at around 90K, the problem existed both before and after it was rebuilt. It did run better after rebuild, but this problem never went away. The rebuilder did not have any idea what it was that was happening. The fluid is not low, never was, and it is not burnt as far as my nose can tell.

Thanks for any ideas..............T

Reply to
Thermionic
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Ok first question. Are you sure that the TCC is in fact engaging? What are your RPM's at cruise down the highway at say 60mph? If they are above

2500rpm's I would say its not engaging at all.

Second question. Did they replace the torque converter when the tranny was rebuilt? If not, it sounds to me like the one-way clutch on the recirculator disc is slipping and that could be causing your problem. It sounds to me like when you are needing some torque the clutch is slipping momentarily and then finally kicking in.

Only other thing I can think of without studying a cluch apply chart or the internals of the trans, would be that the direct clutch is slipping, as you have taken the intermediate band out of the equation by putting it in "2", but the forward clutch is still engaged and operating normally.

Other thing I was thinking about was maybe debris left in the trans cooler could be washing back into trans and causing possible fluid flow blockage.

Anyone else with more trans experience have any other ideas of what might be causing this?

Ford Tech

Reply to
Ford Tech

Thanks for your response.........

RPM is around 1900 at cruising speed on level terrain.

Yes supposedly they replaced it. In fact the converter started getting rather noisy after a while and I had to take it back in for replacement under warranty.

Is the cooler flowing coolant all of the time? Or does it only kick in with some kind of thermostat? The thing definately has much much less of a problem in cold weather. Do you know of a website that has information and hopefully diagrams and pictures that describe the workings of automatic transmissions? I don't really know much about them and would like to understand them better. I would like to take the Ranger to another transmission tech and then be able to understand at least a little about what he is talking about.

Thanks again!!!..............T

Reply to
Thermionic

Ok you have the 4R55E transmission. I would suggest you find a transmission manual for your truck. Helm makes a factory authorized manual for your trans. It will have descriptions for operation, and repair. Some include troubleshooting flow charts to help you diagnose your problem. I warn you, you could be troubleshooting for DAYS if you follow the flow chart to a T... That and you probably dont have all the tools required to do the diagnostics correctly.

Ford Tech

Reply to
Ford Tech

Sorry forgot to answer this question.

Here is a small test you can do yourself at home to check pump flow and cooler flow:

Transmission Fluid Flow

To check for proper fluid flow, use the following procedure:

NOTE: The linkage, fluid and control pressure must be within specifications before performing this flow check.

1.. Remove the fluid level indicator (7A020) from the fluid filler tube. Place a funnel in the fluid filler tube. 2.. Raise and support the vehicle. Refer to Section 00-02 if necessary. 3.. Remove the cooler return line from its fitting in the case (7005). 4.. Connect a hose to the fluid cooler tube (7A031) and fasten the free end of the hose in the funnel installed in the fluid filler tube. 5.. Lower vehicle. Start the engine and set idle speed at 1000 rpm with the transmission (7003) in Neutral (N). 6.. Observe the fluid flow at the funnel. When the flow is solid (air bleeding has been completed), the flow should be liberal. 7.. If there is not a liberal flow at 1000 rpm in Neutral (N), low front pump capacity, main circuit system leakage or cooler system restriction is indicated.

Check fluid cooler inlet tube (7A030) and fluid cooler tube between the transmission and radiator (8005) for restrictions. Check for restrictions in the metal or rubber cooler lines to and from the transmission fluid cooler (7A095) (if fluid equipped). Check and feel all bends for kinks especially transmission fluid cooler rubber hoses, that would restrict flow and could result in transmission overheating or lack of lubrication.

8.. To separate transmission concerns from cooling system concerns, repeat by connecting a hose to the fluid cooler inlet tube

A liberal flow as described by this procedure would be a flow that will take the shape of the hose for atleast an inch after the fluid leaves the hose. With the trans in neutral there shouldn't be very much pressure in the system about 5-10psi.

Then I would do as I recommended before. You can either buy a manual or search the web for 4R55E transmission.

Ford tech

Reply to
Ford Tech

Thanks again for your help. I will post anything I find out at a later time, if its worth posting.............T

Reply to
Thermionic

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