11z71

iTrader: (10)

Hey guys, so Friday night I buttoned up the install of a new RPM level 5 4L65E and Circle D converter. Yesterday morning I took it out for it's maiden voyage, It will not shift out of 2nd gear on it's own or manually. It will just pull all the way up to the rev limiter and doesn't even attempt to make the upshift. The rest of the transmission functions perfectly. This morning I decided to run it down the road again and hooked up my laptop with hp tuners scanner and when I command the shift manually, it will shift into 3rd, then 4th on it's own, then lock the converter and all is good. So my question is what should I be looking for? Does this sound like a tune related issue or mechanical? I thought maybe a bad 2-3 shift solenoid but am doubting that would be the case if it would upshift when commanded? Any insight would be awesome guys! Thank you!

bbond105

With Hp tuners did you notice if the PCM was commanding the shift on its own. If the shift is not being commanded automatically it could be a tune issue or a defective engine sensor. Most likely a tune issue since only one shift is affected, but check for any stored trouble codes and the operation of the TP and MASS sensors. FYI the PCM turns off both shift solenoids for a shift into 3rd gear.

11z71

iTrader: (10)

I didn't notice to be honest, I'm not real affluent with the software to be honest and didn't know you could watch the PCM command the shift. I can tell you the old tranny shifted fine and that same tune is in the PCM. I have changed nothing myself as far as that goes.

bbond105

To diagnosis your problem you will need to know if the PCM was commanding the shift and then we can go from there.

01ssreda4

iTrader: (96)

Yep, are there any trouble codes. Very common for big converters to throw the trans into a limp home mode.

11z71

iTrader: (10)

I just plugged the car in on my lunch break and the only code in there is:
P1810 TFP valve position switch circuit(old)(current)(immature) not sure what that means? I did hear back from RPM this am and they are pretty confident that it's in the tune. The car already had a yank3600 in it before and was tuned for it with no issues aside from the tranny obviously failing just recently.

11z71

iTrader: (10)

update: I was able to mess around with the car a little bit yesterday morning. Using my scanner, as soon I fire the car up it shows D2 in current gear display in HPtuners. I checked the transmission fuse and the fuse was good, pulled the connector off of the transmission and checked all the pins, all appear to be in good shape. When I select drive, it still shows D2 in current gear display but will show D1 if I manually put into first gear. The PCM commands nothing. I need to try to find a schematic for the tranny harness to verify I have 12 volts at the connector and verify good ground. I'm thinking it's either a bad harness in the tranny or bad manual valve position switch.

bbond105

The pressure switch assembly is most likely bad. This switch tells the PCM what gear you have selected through little pressure switches in an assembly bolted to the valve body. I would drop the pan and replace it before I did anything else. Or call RPM and tell them what HP Tuner is showing with the D2 in drive.

mrvedit

Yup, from the code and your last description, I think Mr Bond has the correct diagnosis. Its a $30 part and trivial to replace once you drop the pan.

11z71

iTrader: (10)

UPDATE: I replaced the valve position pressure switch and all is good. It'll upshift into all gears on it's own. Thanks for everyone's replies and help!!

bbond105

Great. I’m happy you got it going. That pressure switch will cause all kinds of weird problems.