Ok, so I've got a 02 1500 2wd with 5.9. I was having an issue with the vehicle staying in OD while on the highway. Super weird rpm fluctuation. Average rpms when it was steady was around 2k at 70mph.

Ended up changing out the OD Solenoid. My fluctuations are gone and throttle response is through the roof, however! My cruising rpms are now about 2400 at 70. Is that an issue or has been **** been messed up so long that j don't know what correct feels like?

I know it goes into OD because I can turn it on/off and rpms correctly adjust for the shift change. i just want to know if something else like the TC is not locking now or something. I'm just unsure. No codes or anything popped.

 

Somethin' ain't right. Could be TCC not locking, but, that would eventually set a code. (you would think....) 400 RPM is a pretty significant change..... I would still question whether you are actually getting O/D......

 

So I know I've got OD. I suppose my rpm is more like 2300. If I turn it off it spikes to about 3000 and I feel the gear change. It's running fine (I think) but I don't want to cause any internal damage. I'm just unsure.

 

Get up to a reasonable speed, so the trans is in O/D, etc, and step lightly on the brake (maintain your speed though.) does RPM change 1-200 RPM?

 

Yes. Did the test at 50 mph

 

Well that's just odd.... With TCC locked, and O/D in, its basically a direct mechanical connection from the engine to the rear tires. I have no idea where the difference in RPM would come from then.

 

When the torque converter goes into lock up, You notice a slight drop on the RPM vs when not in lock up. Have you change the tires to a different size and not the ones that came on the truck from the factory. Or maybe a lift kit? If any to those questions. Did the pinion factor get adjusted too. When to turn the O/D switch off causing the O/D light on the to come on. You should not have overdrive or 4th gear. Your highest gear would be 3rd gear. Push the button or switch to turn the light off. You should feel the transmission shifting into 4th gear or overdrive. I didn't notice if you said if the transmission has had any other repair work other than the solenoid.