Transmission not shifting.

So I have a 2004 GMC Yukon XL 5.3.
Yesterday, I went around did some errands and once I left the store, I put it in drive, everything seemed normal, Yukon shifted from 1st to 2nd and from there my rpm's just kept going up and that's when I noticed it wasn't shifting to 3rd & 4th. Shifts from 1st to 2nd seemed a bit rough though.
Reverse & neutral seem to work fine. Keep in mind that I live in Las Vegas and yesterday's heat was at 117 degrees when all this happened.

Tranny temp stayed at its normal temperature, I ended up limping on my drive home, couldn't go faster than 30/35mph without raising oil pressure too much.

The truck has about 145k miles.
Any ideas on what could be wrong?

Around 4/5yrs ago, my dad ended up replacing the transmission speed sensor. The Yukon was stuck on first gear, it was diagnosed it was just the tranny speed sensor. I checked that yesterday and the inside of the plug where the connector and pins connect, there was tranny fluid, enough to completely saturate the inside of the plug. I know if you have a faulty speed sensor it can cause a number of odd things to happen without throwing a code.
Could that be my problem?
Or maybe the shift solenoids inside the transmission?

Any help would be greatly appreciated!
Thank you!


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My bet would be the shift solenoid inside. I had a similar issue and it turned out to be a bad connection on the wiring harness. But I was getting a service engine light and the speedometer wasn't functioning.
If you end up doing the shift solenoid inside I'd suggest that you get both. From my research that sounds more likely to be your issue. There are some write ups on testing them with an ohm meter but since I have 180k on it I decided it was time to replace them either way.