have a 2001 F250. The U-joints and Hanger berring are going bad and will soon be fixed but recently the "overdrive off" light on the shifter is flashing. What does that mean?

 

It means something is wrong with the transmission system. It could be a wiring problem, a sensor problem, a mechanical problem, or an overheating problem. The only way to know is to read the codes with a compatible scan tool. The places that read codes free don't have the right tool.

 

That's a code in the trans, it's calling for help. Not a good sign, is that a 7.3L diesel?

 

run for the hills its gona blow!

 

Thanks guys even tho that is sooo far from what i wanted to hear. Yes it's a 7.3 and it has 159000 miles on it and its been sittin for almost 2 yrs bc i lost my lisence. I havent had the first bit of problems out of it until now...right bf i get to start drivin again of course. I have a programmer on it that pulls codes and i tried that and nothing came up. Could the programmer be the problem?

 

It's not likely your programmer's the problem here. It is likely, however, that the programmer caused the problem. Most tuned diesels put out WAY more power than the truck was designed for. In this instance, the weakest link will fail first...which would happen to be your 4R100 transmission.

The tranny was NOT built to take the kind of abuse meted out by a chipped engine. If you're gonna play, you're gonna pay.


Now that I'm off of my righteous rant, I have some useful advice. I think. Neither your programmer, or most OBD-II scan tools, will read transmission codes. Has to be accessed by a transmission compatible scan tool. The kind your local Ford dealer has.

Some, such as Autotap and AutoXray can have the capabilities of reading enhanced codes, but I'm not completely sure if it'll see your problem. Mark K will likely have some input here...

 

There's a sensor on the differential that may have gone bad. It's not too costly to replace if you do it yourself. If that doesn't solve the problem and you've cleaned all the electrical connections it's off to the dealer.

 

I disagree with throwing the parts store at a truck without properly diagnosing the problem. Throwing parts at it without seeing the code is financially reckless. I've done it before, and it gets EXPENSIVE.

 

haha, that is so true.

 

Normally I would agree concerning replacing parts but in this case, and because differential speed sensors have a habit of going bad, a replacement Motorcraft sensor runs $35 on the internet. That's less than what a dealer would charge for a code read. If the sensor is not the problem then it's off to the dealer or a trans specialty shop.

 

You have a point there about cost. However I don't think we have enough information. The OP didn't mention how the truck is driving. If it seems to be driving fine you likely have a good idea. However, with the tuner he's running as well as the miles on the truck, I think it's likely there's something wrong internal.

To the OP:

How does it drive?

 

It drives fine for the most part except for the torquing up and the driveshaft finally catching up and banging due to the u-joints being worn and hanger berring being shot. I have half the driveshaft out now to replace the u-joints but the bolts that hold the hanger berring in are stuck and i dont have a 16pt socket to get the bolt out of the side that bolt it to the transfer case. Therefore, the second half of the driveshaft is still in the truck. This mess is driving me crazy.

 

I already did.

It's WAY premature to think the trans needs to be replaced. It's not really possible to find and fix the problem without the codes. They are there, you just don't have the right tool to read them.

 

Ok so who has the right equipment? A dealer? And whats a rough estimate on what it cost to get this eqipment used?

 

Many independent shops have the right tools, too. It will cost about $50-$100 to get the codes read.