W250 wont shift into OD,Sometimes-Help Please

[Flash1034]

My 93 W250 will occaisionally refuse to go into overdrive. What would cause this INTERMITTANT AND TEMPORARY condition?

Thanks,

RamBill

 

[jsimpson]

The electrical plug that connects the computer to the transmission gets loose and roitted, and then fills with water. Pull it loose, clean the contacts, fill the boot with grease, push it back on and secure wire a wire tie.

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http://coffeewithJesus. homestead.com/web1.html 89 1-ton, Amsoil System 3000 5-30,K&N, cleaned-up exhaust with Dynomax straight-thru, rebuilt injector pump, thermostatically controlled twin 14" Permacool electric fans, intercooler, modified 518 OD transmission, Gear vendors OD controler, Reese Titan 2. 5" receiver, R-134 refrigernt, louvered front fenders, 93 aftermarket smoothie grille, new Dupont Chromacolor black, black-and-red rubber rubstrip, black headlights, powdercoated bumpers; 78 35'Avion, 93 Lance 900 slide in with generator and power jacks. To see my truck, Click on: http://albums.photopoint.com/j/AlbumIndex?u=1169022&a=10097213&f=0

http://albums.photopoint.com/j/AlbumIndex?u=1169022&a=10097213&f=0

Jesus saves!

 

[dslcummins]

Check your TPS, I've had problems where it wouldn't shift into OD and I've had problems where you may be cruising down the highway and all the sudden you are in third gear. It was the TPS.

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92 2500 Reg. Cab LE
Dark Spectrum Blue and Silver 4x4 Auto
PW Injectors, 238,000 miles, 16cm2 housing,
Isspro guages, DTT torque converter 91%,
modified vb, new 518 trans, Mag Hytec
transmission pan, second gen gear
shift lever with OD button.

 

[fastmark]

I was having the same problem. At 135K I had a transmission mishap(my dumb fault that I really don't want to discuss in public). When I had the transmission overhauled they found the separator plate in the valve body worn almost in two in several places where the steel balls moved around to block the fuild from hole to hole. My transmission has shifted a million times in stop and go traffic. I suspected a faulty TPS. I did not change the TPS and now it works fine

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Mark Faught, 92 ext cab service truck and a 84 crew cab one ton dually with a 91 cummins and NV 4500.

 

[Bill Kondolay]

All of above are possible, also the temp sensor. I have found that the temp sensor to be 40% of the od headaches. the temp sensor is located on trans cooler line next to trans shifter linkage.

Bill

 

[Flash1034]

Thanks for the replies. I have now checked the connections and they appear OK. Is there a way to "check" the TPS and the temp sensor without replacing them to see if they are the source of my intermittant problem?

Thanks,

RamBill

 

[GeneH]

#ad

There are two temperature switches that will inhibit shifting into overdrive. The engine coolant temp sensor and the transmission thermo switch. Here is the page from the service manual describing their functions.
The transmission thermo switch can be checked with an ohm meter,it should be closed. I suspect the engine coolant switch should be the same but I can't find the procedure in the service manual to verify that.

Gene
92 350 4x4

[This message has been edited by GeneH (edited 05-15-2001). ]

 

[GeneH]

#ad

Excuse the quality of the photo.
All of my not shifting into overdrive problems were a result of an intermittent TPS signal. The top of the TPS can be remove using a small pointed object to scrap the glue away from around the edge.
Clean the inside with some electrical contact cleaner. Put a little dielectric grease on the wiper contacts and glue the top back on. While the top is off drill a small hole that can be pluged so the next time the TPS is intermittent it can be cleaned with out having to take the top off.
This will only fix a dirty TPS. It will not fix it if there is a open spot that the wiper rides across. Sooner or later they have to be replaced. I have been able to extended the use of a TPS by the method described above.
Good luck
Gene
92 350 4x4

[This message has been edited by GeneH (edited 05-15-2001). ]

 

[IdahoJim]

If the speedometer also quits, along with the OD, the problem is the distance sensor on the transmission. Mine went out at about 130,000 miles.

 

[IdahoJim]

If the speedometer also quits, along with the OD, the problem is the distance sensor on the transmission. Mine went out at about 130,000 miles.

 

[GeneH]

Just geting this to the top.

Gene

92 350 4x4

 

[BushWakr - RIP]

May I suggest before you take the TPS apart you check the operating voltages. There are a number of posts regarding this but if you need more info I can email you the page from the service manual on this topic.

Case5000D has info I sent him on this as well.

Let me know.

Regards, Bush'

 

[CBratten]

My truck has just started shifting in and out overdrive at speeds about 42 to 48 MPH when going up a grade. Is there an adjustment to make it less sensitive?

 

[GeneH]

The only adjustment I know is to set the TPS voltage to 1 volt at idle and at full throttle it should be around 3 volts.

To measure the TPS voltage connect the positive probe of a volt meter to the middle wire in the TPS connector( I use a safety pin to push into the connector) and the negitive probe to ground. The connector needs to be on the TPS during this check. There is a 10 mm bolt under the TPS that is turned to adjust the voltage.

Gene

92 350 4x4