2003 Dodge 1500 Van here, Auto OD tranny, 5.2L V8 engine. I just replaced the radiator on my van. Hooked everything back up and gave it a test drive, drove perfectly but the lower radiator hose was leaking at the connection because I didn't put the right type of clamp back on the hose. SO, drained radiator put the correct clamps back on the lower host and refilled... then went to take it out for a test drive and it was driving like crap. I can't describe precisely what's happening but I'll do my best. Basically the engine seems to be reving really high now when trying to shift. It's almost like it's shifting a tad late now, and then holding onto each gear a bit too long. When the shifts occur they occur quite smoothly it just seems that now the engine is working way to hard to get the job done. This all happened in a matter of less than 24 hours.. it went from driving perfectly to driving crapily and I don't know what happened. Any ideas? What could have happened so suddenly to cause this issue? Could there be something I did when replacing the radiator (my first instinct on this is no)? Any assistance would be greatly appreciated.

 

Update: I think I jumped the gun in blaming the tranny. I noticed before that there were times when driving where the van drove perfectly so I decided to take a test drive this morning and pay extremely close attention to the tranny. What I found that was during about the first 5 minutes of driving I was exeriencing the high reving issue, but the shift points were spot on and smooth... tranny seems to be working just fine, but something is causing that engine to have to work very hard. A friend of mine seems to think that I need a new fan clutch... I"m not sure on that, but could that be something that would make my engine have to work so hard like that?

 

A fan clutch can fool you, I once stupidly had a transmission replaced and later found out that the fan clutch was kicking in and sounding like the engine was revving way up, if you have a tach you can watch it and see if your revs are up or not. Tracka96

 

Here's an update. I've replaced the fan clutch and although it turns out it did need replacing it wasn't the cause of this particular problem. Another thing I've noticed is that this issue only starts once the van is completely warmed up, i.e. only when the engine is hot. I'm at a loss on this one. Oh, thought I'd mention something else I've noticed... when shifting through the gears I noticed today that although I can shift into 1st without issue and drive in 1st without issue the indicator on the dash never highlights the "1". Anyone know why that is?

 

Assuming your old and new radiator has a tranny fluid cooler in it, have you checked the fluid level in your tranny? You could be around a quart low.

 

Yes I have the tranny cooler and the fluid level was the first thing I checked. I should emphasize that as far as I can tell the tranny shifts when it should, and it does so smoothly... the engine is working really really hard to get the job done... and only when warm. It's also affecting my mileage.. I'm on track to get anywhere between 80 and 100 miles less than normal on this tank of gas.

 

I was looking through Allpar for this photo of what the tranny cooler internal to the radiator looks like. Even though You've ruled out the tranny, it is interesting to see.

http://i262.photobucket.com/albums/i...1/100_3139.jpg

Check the PCM for codes, then disconnect the battery for a while. Perhaps you have air in the block and the Coolant temp sensor reading incorrectly because of this.

And check all your grounds, and any wiring near what you removed to replace the fan clutch and the radiator.\
Hope you figure it out.

 

OK so what I know so far is that the problem only occurs once the engine reaches operating temperature (and during the 1st min of driving, where it's normal for the engine to rev a bit high). I know it's not the fan clutch. I still don't think it's the tranny, but a friend seems to think it might be the torque converter. My question is, if it were the torque converter shouldn't I expect that the problem would be evident all of the time, just not when it's warm?

BTW, just checked the PCM for codes and there are no codes stored.

 

Do you have a tachometer on the van? If not, do you know anyone with a scangauge that you can borrow to see just what the rpm's are doing when the trouble occurs, as compared to when it runs right? Tracka96

 

Well, I finally decided that I'd take it to a tranny shop and have the pan dropped so i could check things out for myself. Sad news is that it appears I'm going to need a new tranny, or a rebuild. Fluid was burnt and there were a LOT of metal shavings in the pan. I guess the couple of times it ran kinda hot before I replaced the radiator was enough to push the tranny over the edge.