I have an intermittent problem losing 1st gear and 4th (OD). It is a 46RE trans in 97 with the 360.

I get a P0753 (3-4 Shift Solenoid) code. I'll clear the code and drive for a bit and a day or two later it comes back. If I shut the trruck off and put it in park it ocassionally works fine again (check engine still on because code not cleared, but shifts fine).

I am guessing that I might have an electrical issue with the 3-4 solenoid, but I cant see anything in the service manual that would relate to why I lose 1st gear as well. It just runs between 2nd and 3rd until it seems to fix itself and then I have all 4 back.

Any insight as to why 1st gear might be tied into this issue?

 

I had similar issues with my 46RE. It progressively got worse and totally died after about 3 months of problems. Turns out it was the overrunning clutch assembly in the OD had failed and gummed up all the VB passages.

You can read about it here..https://dodgeforum.com/forum/2nd-gen...y-rebuild.html

or see the pics here...http://my.att.net/p/s/community.dll?...pid=404015&ck=

 

Are you sure its shifting from 2nd to 3rd and not just staying in 3rd? If you have 3rd gear starts with no shifts, that is limp mode.

I would pull the pan and ohm check the 3-4 shift solenoid. More than likely its dead.

 

Mine did that and I found the wiring harness unplugged. Drivers side toward the rear of the tranny is where mine was unplugged. You might check that.

 

Thanks for the ideas. I am going to take a look at this weekend and I'll post back. As I have been driving this week I have bene noticing that if I stop, put it in park, shut the truck off and restart it will run through all 4 gears (and the converter locks up in OD), but then it drops out of 4th/OD and back to square 1.

I am 95% sure it is a 2nd gear start and there is a 2-3 shift occuring, but I will doublecheck since you mentioned it.

 

Well, I took a look underneath and found that the two vacuum lines under the rear of the tranny that come off the transfer case and connect to steel lines for the CAD solenoid were off. I haven't yet looked at the vacuum schematic to see if these being off could create a vacuum leak and if a vacuum leak would impact the trans operation.

I also double checked any of the electrical connections I could find and they all appeared to be solid. I cleared the DTC and drove and it was fine. I'll see what happens tomorrow morning.

Monte - is it safe to assume if the 3-4 solenoid is done, that it would be a consistent problem and not intermittent?

 

Not always.

 

Well, I took the truck out this morning and it was fine for about 10 miles. Thought I had it, maybe it was just a loose wiring connection. But then I lost 4th and 1st. Got to our destination. Left about 2 hours later and fine for the rest of the day.

I did confirm that it is starting in 2nd and shifting to 3rd. It is not starting in 3rd.

Until next weekend...

Monte - thanks for the 3-4 solenoid clarification. I'll have to check it when I can get enough time.

I'm thinking PCM at this point.

 

OK. Think I am on the home stretch, I hope. The tranny has been intermittent all week. No rhyme or reason to when it has all four gears or when it loses 1st and 4th.

I actually took the time to read through the powertrain service manual and a P0753 code guides you to a TC-50A test. The first step in this test is to do the following:

Remove the transmission control relay in the power distribution center. Then test the resistance between the transmission control relay output circuit and the 3-4 solenoid circuit at the PCM connector (#21 on the PCM connector). I had 36.5 ohms. The manual states that if the resistance is between 26 and 40 ohms to replace the PCM. If it is over 40 ohms you go on to testing some other circuits.

So as of now I am going to go with replacing the PCM as the diagnotic test and my gut both are pointing to that. I'll post back in a few weeks with the results.

 

OK, here is the last follow up. I replaced the PCM with a reman unit a few weeks back and no problems since. So far so good.