I have a 1994 F-250 XLT heavy duty model. No warning lights are on. A few times a month my transmission will start shifting hard, kicking into the next gear. The odd thing is, if I reset the computer it stops. Shifts smooth as butter. The fluid is a vibrant red and the fluid looks great like it's new. Any idea what is going on? I'm getting tired of having this happen. The truck has 108,500 miles on it. Thanks

 

That's what happens when the computer detects a transmission problem. There will be a code stored in the computer's memory. You need these codes to find out what's wrong.

Here's how to get the codes: Ford ? OBD Trouble Codes

 

Do I have to use that method? Or can I use an OBD II reader? I think the OBD II goes back to the year 1990, right?

 

Also I saw in the link you gave me it says for turbo diesels. I have a 460 in mine.

 

OBDII goes back to 1996. There is no way to connect an OBDII reader to your truck.

You can get an OBDI reader for about $30 at most parts stores. That link is for a diesel, you didn't say what engine you had. The method to connect to read the codes is the same, but some of the codes are different. Get the codes and google them and you will find out what's causing the problem.

 

OK, thanks for all the help man!

 

I had a 1997 F250 heavy duty with 5.8, at 50ish thousand miles it started to bang hard into gears. Truck had a plow on it till 37k when I bought it and removed that trash. After some trips to a few shops I settled on one and had the trans pulled. TQ converter went and trashed the system with material

 

Yea, I just got the code 628 which is "Excessive Torque Converter Clutch Slippage". Did you have to replace the entire transmission and the torque converter or just the converter?

 

I just got the code 628 which is "Excessive Torque Converter Clutch Slippage". Not too happy about it right now, but what is a fix for this issue?

 

The first step is to clear the code and see if it comes back. This code has a history of setting when it shouldn't. If it comes back fairly quickly, then there is probably something wrong. If it takes a month or two to come back, you can just clear it again.

The most common cause in this vintage transmission is a crack in the torque converter clutch apply piston. This leaks pressure that is supposed to hold the clutch engaged. The crack will continue to propagate, and leak even more pressure. As this happens the code will set more often.

One way to verify that this is the problem is to look at the front face of the torque converter. If the clutch is really slipping the cover will get a blueing effect on it from the heat from the slipping clutch.

The fix is to replace the torque converter. Once the trans is out many people rebuild it. That usually isn't necessary, but a decision that needs to be made.

 

I reset the code this morning and drove only 20-30 miles city and highway driving. Went through all gears, and only a few miles from my house it started kicking again. Ran the obd self test and got the code 628 again. Its coming back a lot now. I'll check the front of the torque converter for blued metal in the morning. Thanks