On my truck, every now and then, when i go to merge with traffic, it'll shift into second fine, but when it hits 3K RPM (~50 MPH), it'll shoot into neutral for about 1 second (while hitting about 4K RPM) before falling into third at about 2100 RPM. Is this a valving issue or lack of fluid/underfill or computer issue?

 

how long since a fluch? sounds like a band issue to me...

 

It's the 45RFE- there are no bands, it's a clutch-only transmission from what i've read. It's the same as the 545RFE after a computer hit. (If you look it up, the only difference in the two is that the 5th gear in the 545 is a combination of the 4th and 1st gear clutches at once, otherwise it's a 45)

It's got 103,100 miles but we just got it from a dealership at 102,000. Also, carfax showed that the PO did EVERYTHING at the dodge dealership from the beginning.

 

Nothing to do with the tranny issue but Do NOT put all of your cookies in one jar based on a Carfax report. I've junked half a dozen total loss cars ......... with CLEAN Carfax reports! I've never seen a Carfax report showing any maintenance records ....... only emission inspections, title events and accident reports.

 

The one for this truck was 4 printed pages long- mostly oil changes done every 3000 miles and yearly inspections, all done at the dodge dealer it was bought from.

 

they show maint records dependign on who does them..

 

i have a manual tranny-my 96 prism does the same thing- it has electronic shift solenoids in the pan.are the dodge auto trannys controlled by the ecm?

 

yes they are, the ECM controlls second gear for either 1.67 or 1.50, which is chosen based off the TPS, wheel speed sensors, and transmission input shaft speed sensor i believe? (i'm not a tech so idk)

 

you might want to have the CVI's read (clutch volume index)
for the 45 auto at a dealership to see if any are high
indicating that clutch is leaking/bypassing/sticking

you can bone up on the 45 internals by reading this:

http://www.motor.com/MAGAZINE/Pdf/062000_04.pdf

 

My wifes Saturn does the same thing, its called shift flair. Its a defect in all of the Saturn Ion transmissions that GM got from some Asian company. As far as I have seen on the Ion, its a computer control problem and if you experience in infrequently, it should not cause increased wear on the transmission. So far we have put 50k miles on the Ion (in 18 months, bringing the total to 100k) with no increase in shift flair and no other compaints from the tranny. Watch to see if it happens more often, which is a sign of damage.