O/T: '90 F250 7.3 auto trans questions

Just picked up this truck. It has sat for several months. Put one new battery in it and got it running. It runs pretty nice, except it starts to stumble after idling for several minutes. Likely needs some fuel system cleaner run through it.

Engine is a 7.3 non-turbo, 160000 miles. The trans goes into gear solidly, doesn"t slip at all. But, occasionally, it will shudder slightly at the two shift points after 3rd gear. Well, TCC lockup may not be considered a shift point, but you know what I mean. This does not happen every time it runs through the gears. Generally, if you drive it easy, it"s fine. Sometimes, when slowing down, it seems to lurch a bit as if the torque converter isn"t unlocking properly.

I"m leaning toward a problem with the torque converter. Am I going in the right direction? Or is there a completely different problem with the transmission? Should I sell it for parts or invest the money to fix it?

I don"t really need it. Body is mildly rusty, cab floor starting to go.

The guys I bought it from said the transmission is a Ford rebuilt unit. They also said the torque converter had some water in it but they "flushed it out good" before they installed the trans.

Your time and advice is appreciated.

Thanks,

Anthony

I think this model used a unit mounted on the injector pump to control trans shift functions, but not sure. should be mounted on throttle linkage shaft @ pump, has rubber hoses running to it to control modulator vacumn. might ck this out first.

If it is an E4OD, there is a button on the dash to lock out overdrive. E4OD is different in that it uses fluid pressure to release the TCC and spring pressure to apply. Sounds like the TCC control valve in the fluid pump has a problem.

It's not tripping into "limp mode" at all? Often problems like you described are caused by the FIPL switch. It is a variable resistor that attached to the throttle-shaft on the fuel-injection pump. It's adjustable with slotted mounts and is also easily replaced. It works, more or less as a throttle position sensor so the trans knows how and when to shift.

If that transmission has had water in it, it's not long for this world. The water will be absorbed into the friction material of the plates in the trans, and also the torque converter clutch. When the trans is at operating temperature, the momentary heat generated during shifts and lockup is enough to eventually steam the paper lining off of the plates. Once it's in there, there's no way to get it out of the linings. How long the trans lasts is only dependent on how much you drive it and how hard you work it.
I work in a transmission parts warehouse and have firsthand knowledge of what water does to transmission plates. If you don't need the truck I'd part it out or get rid of it.

Drain the fluid out and replace it with new. The fluid has an additive to reduce the static coefficient of friction below the dynamic coefficient which eliminates the stick-slip that you are experiencing during the shift. Don't do the flush process. You may have to drain and then add four quarts at intervals of 50 miles of use because I don't believe the converter has a drain plug.

Dr. Tranny's Instant Shudder Fixx google it,,,,if after 100 miles the shutter is gone make plans to change the fluid and filter... This will eliminate the fluid as the issue...