Ok folks. I`m lost here. I have a 2004 Ram 3500, 5.9 diesel, auto trans w/overdrive. One day I drove it about 300 miles. It shifted great. I got home and parked it. 2 days later I git in it and reverse and 1st gear worked fine but then just slipped in 2nd gear. I always change the fluid and filter every 10,000 miles. It seems to only have the flat filter too. Fluid level was good. I changed the fluid and filter. Still worked good in reverse and 1st. I drained 1 qt fluid out and added a qt of Lucus transmission treatment. I drove it up and down the road and it stifted into 2nd kind of hard but didn`t slip until it tried to go into 3rd. So I took it home and it sat for about a month while I tried to figure something out. Yesterday I was going to take it in and have it put on a DRBD scanner but it slipped again after 1st gear. So now it sits again. I called tranny shops and explained to them what was happening. They all said it sounds like something is getting plugged up. I changed the shift speed sensor and when I pulled it out it had black gunk of the tip.
So my question is..If I drain the fluid and drop the valve body, will I be able to flush it out (the valve body) and reinstall it? If there is a blocked port, is that where it most likely will be? With the valve body out, can I flush the gunk from the bottom of the inside on the transmission? I am unemployed and don`t have the money to take it in to be fixed so if it is something I can do myself, I want to at least try. I have a lot of common sense and have helped rebuild a couple transmissions in the past. I also understand the service manual. I just don`t want to go through all that work to find out what I was trying to do won`t help and it still HAS to be taken into a shop. ANY help will be great. I need my truck to get a job. It`s a 1 ton, 4x4, dually diesel. I`m not afraid to to attempt this either as long as it doesn`t get too deep into it. Thanks.

 

I want to add the check engine light doesn`t come on and no codes come up when read with a regular code reader.

 

Slipping in 2nd usually means your bands are out of adjustment or worn down too much. How many miles on the truck? You can try to take the VB out and flush it, it might work, it might not. I would suggest at least adjusting both bands and cleaning the two pressure sensors in the VB and possibly upgrading the one to a BW 50185 if you can. When you do the adjustment, if you have less than two threads showing afterward then its about time for a new band.

 

As it turns out, when I got it fixed, the guy told me that when these transmissions were made that the groove for an O-ring was cut too deep and after the o-ring got even a little worn that it stopped sealing and then problems start to arise. Dodge put a thicker o-ring in the oem rebuild kit to fix the problem.

 

dammit. I was just gonna say that about the O-rings..hahahahaa seriously though.

Good to hear you got it fixed. Thanks for posting back the solution!