Eric Tribble

98' Ford F150 XLT 4.6L V8 (Automatic)

Truck starts up good, drives at first like there is no problem, but once I get past 30MPH the rpm's just kept going up and it no longer shifts up. I have to wait for my speed to get back to 30MPH or lower before the transmission kicks back on.

I'm not a mechanic but am able to replace what I can. So far I have:

- Replaced the transmission fluid and filter. A few metal shavings in the pan on the magnet.

- Replaced the rear ABS Speed Sensor.

No indicator lights on the dash, Everything seems fine till I get to 30MPH.

Some people have indicated it may be the catalytic converter, but there's 2 on this truck on each side, and I'm afraid of just removing them and letting the exhaust just flow into the firewall. I have no replacement pipes so it would just be without the catalytic converter/exhaust pipes.

Anyone have any recommendations?

RLXXI

Sounds like your transmission is shot.
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Eric Tribble

But it runs fine till then. Doesn't even try to shift to the next gear. Is there a sensor that makes the transmission not shift if a gear is damaged or broken? Wouldn't it show more signs of damage then just not shifting into 3rd?

RLXXI

Transmissions can do all sorts of weird things, one symptom of them needing repair is not shifting after 30 mph. There is a slim possibility of a sensor issue, you need to have the truck scanned.
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Eric Tribble

Do you know about how much on average a scan cost now-a-days?

RLXXI

Depends on the shop. Figure at least an hour labor on the diagnostics.
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F150Torqued

Could be as simple as a Shift Solenoid, or even a solenoid wiring connection. The challenge might be finding a qualified transmission technician that won't try to parlay the problem into "replace the transmission". On that score, I have no suggestion.