48RE behavior question

[JohnCollins]

I am trying to decide if I need to take my 2004 2500 QuadCab to a second Dodge service facility for an opinion. The truck is new to me and has only 29k miles. It shifts fine under normal conditions. If I get into the throttle (1/2 wot or more) and accelerate thru the gears, there is a split second between 4th gear and tc lockup where the engine speed increases then it locks up firmly. It sounds as if the clutch slips then catches firmly. I took it to a country Dodge dealership down the road. The tech drove it (brought his test box along), said the kick down cable needed adjusted. He did that, and it improved things a bit. He drove it for 30 mins and concluded that it is normal and said that the engine makes so much torque it is probably a protective feature in the programming to help save the tc clutch. He tested the tc clutch and said it was not slipping (stalled the truck using the test box, pretty cool). The fluid and filter were just changed although I did put Valvoline full synthetic ATF+4 in it which he seemed to think might not be a good idea. Plan to drain and refill with Mopar this weekend. Any advice, shared experiences, etc. are appreciated by this new member.

 

[cerberusiam]

As exlained to me, what you are feeling is the converter not filling correctly and unable to apply the lockup clutch correctly. It usually happens under hard acceleration and is happening because the pressure regulator is usuing the fluid to maintain pressure and not by-passing enough to keep the TC filled. Its a common problem on just about all the lockup transmissions out there. The fix is either a VB kit or a different pressure regulator valve that will bypass enough to keep the TC filled.



It is not a good thing to have happen consistently and can lead to transmission damage from lack of apply flow and lube flow.



It does not show up as an issue on any of the scan tools and as far as DC is concerned it doesn't exist as a problem.

 

[JohnCollins]

As exlained to me, what you are feeling is the converter not filling correctly and unable to apply the lockup clutch correctly. It usually happens under hard acceleration and is happening because the pressure regulator is usuing the fluid to maintain pressure and not by-passing enough to keep the TC filled. Its a common problem on just about all the lockup transmissions out there. The fix is either a VB kit or a different pressure regulator valve that will bypass enough to keep the TC filled.



It is not a good thing to have happen consistently and can lead to transmission damage from lack of apply flow and lube flow.



It does not show up as an issue on any of the scan tools and as far as DC is concerned it doesn't exist as a problem.



Sounds like to me you have experienced the same thing. In my typical manner of driving, it does not happen. If it is normal, I can relax and just wait til warranty expires and do the valve body and tc mods just for kicks. One other thing I noticed is that when I tap the brake when in 4th gear lock-up, it does not unlock. I kinda thought it was supposed to unlock and go back to 4th. Thanks

 

[cerberusiam]

Yes I ave noticed it,among other annoying traits. Others have seen it more and several discussions ensued. This is the best description I've run across so far for the problem.

One other thing I noticed is that when I tap the brake when in 4th gear lock-up, it does not unlock. I kinda thought it was supposed to unlock and go back to 4th

My 05 doesn't but it has a different setup and program. What you have is what you have. There are some differences between years and half years with the operation.



If you like the way it works, DO NOT let the dealer flash the ECU as it may change the operation of the trans.

 

[CUMMINZ]

My 2004. 5 did that. My 2006 does not.

 

[JohnCollins]

Warranty pays off!

Well, I wasn't going to, but I went ahead and made an appt with a second dealership to get a second opinion. The trans seems to behave as described earlier with even less throttle than previously. At half throttle, it will flare every time before locking the converter in 4th gear. THe tech drove it and said he has seen several trucks come in with this same complaint and that he has put new convertors in a few of them. He did not want to condemn the convertor until he ran a test. I knew what test he planned on running and figured it was a dead end because the previous DC tech at the first dealership said it held fine. Well, the first time he ran it (the test locks up the tc clutch in drive at idle to see if it will stall the engine) it seemed to slip a little and then stalled it. He ran it again and it seemed to drag it down rather slowly before stalling. Ran it again, same thing. He said, "Well, you're gonna get a new convertor. " I did not argue with him and figured it couldn't hurt. May or may not solve the problem, but at least it will rule out the tc and I will have a new one. I figure it is slipping a little but not too bad. But it is probably headed on its way out. I asked him about the 48re in general and he said it was a really tough unit and that they had not seen much trouble with it. He said it was kinda unusual to have a bad tc with only 30k miles.