Tranny Problem?

[The02riot]

Well I have a problem and I'm bringing it to ya'll here for my first post. My Ranger is a 98, 4.0 V6 4x4, with 169,000 miles on her. I just got this truck around Christmas time and the old man who had it took extremely good care of it. He has all the records of every oil change and everything. Right now the truck seems to jerk forward and backward when I get to around 35mph. Mostly when I get past that speed up to past 40 then she's alright and sounds fine. It sounds like it's going in and out of gear or in and out of OD. I'm not really sure on the motor, that's not my specialty.

I also took the exhaust off today and am running just straight cat. converter. What are the advantages and disadvanteges to this? It also pops when I run it, how do I fix that?

 

[MAKG]

The disadvantages are the $2500 Federal fine and excessive pollution. There are no advantages. This isn't a 1975 big block.