Truck jumping ahead?

[fissionbait]

So I'm having this increasingly annoying problem with my Ranger. It's a 4.0 and has this extremely harsh "clunk" and surge when ingaging 2nd gear. It will rev up a bit but you can hardly heard the motor. It just sounds like what I think is the torque converter just spinning until it clunks into 2nd gear. Anyone know what can cause this?

 

[jlsparky7]

I had the same prob with my 2001 3.0. 3 Things that helped me a TON were....
Clean the MAF and IAC as well as the throttle body. I also changed the differential fluid and noticed a huge change. If that doesnt fix it look into your speed sensor on the differential.

Hows the trans fluid level?

 

[fissionbait]

Tranny fluid's preme, just had it changed a couple weeks ago with a new shift solenoid. One thing I think I'll try is putting the old paper air filter back in. I've cleaned the MAF lots of times but I think it could be the high flow filter that messing with the fuel mix.