Transmission

[twacker4]

I have a 2006 Dodge 2500 4X4. I currently have a Smarty and 5in exhaust and AFE intake and gauges. I bought this truck used with 74000 miles and the trans was fried. It now has 85xxx and the trans is still fried and I need to do something before it gets to much hotter down here in San Antonio. The reason is whenever I get stuck in stop and go roads and such my temp gauge climbs and climbs but if I stay on the highway (no traffic just steady cruising it) it stays down near 150. When I get in stop and go stuff the trans temp will climb to 210 then crazzy stuff happens. I'll stop at a light for example, once green I'll pull slowly through. Around 1st gear, the Boost gauge and rmps go crazy and my turbo like shutters 2-3 times then it finally goes through gear, same thing at about 25 - 35 mph. But once I get up at steady constant speed (which rarely happens because of traffic) the truck cools down. In this South TX heat it only takes about 25 -35 minutes of stop and go conditions to start acting up. Even in the cold weather after bout 45 to an hour of stop and go it'll do it. If I get in a hilly area with lots of lights, IT SUCKS!!! I believe it's like real bad slipping but I'm not sure. The only time it doesn't have this problem is steady highway. If I can drive 45 and up at constant speed, not stopping, it's fine. I already paid 300 to have solenoids and fluid changed and that did absolutley NOTHING...I drive fast but I don't race or anything so I wanna rebuild the trans but not billet everything like everyone says.. I guess I want TC and valve body and not completely sure if I need input but I do know I just want a whole rebuilt in some fashon transmission (not just stick new parts in this one).. My only other mod I want is a Airdog but I still ain't gunna go crazy with Smarty and such.. I wanna get this done probley next month so if you wanna toss some ideas at me that'd be awesome.. and if you got any ideas of what the problem is throw em at me.. thanks

[Relentless Diesel]

We may not be able to help you with these problems.

First off, the transmission will ALWAYS be hotter in stop and go traffic. There's no airflow across the coolers. And you have a heat exchanger which puts heat INTO the transmission from the engine coolant. The transmission will get at least as hot as the engine temp (200-210°).

The torque converter creates the most heat at idle in gear stopped. So that adds to the heating issue.

Aftermarket torque converters with tighter fluid coupling will actually run hotter in stop and go traffic than stock ones. An hour in stop and go is brutal. Adding additional coolers inline will do little to nothing to cure this problem with no airflow.

Putting the shifter in neutral will allow the torque converter to stop shearing the fluid and minimizes the heat buildup, but you still have the heat exchanger bringing transmission temps up to engine coolant temp.

This is why your factory service manual requires you to service the transmission more frequently for in-town use than for highway use.

You mentioned not wanting someone to "just stick new parts in this transmission." That's all you're going to get. In '07 you could still get new 48re's from the dealership. But it's no longer the current transmission and hasn't been for 3 model years now. All that's available is remanufactured 48RE's. You are simply getting someone else's failure with a few new parts in it. The only difference is who you are paying to stick the new parts in and how thorough are they at paying attention to small details.

Transmissions I build are gone over internally with a fine toothed comb. Every part is inspected and replaced if any problem is found.

As for diagnosing your current problem, I'll need a better description of the problem. You said when you pull slowly through an intersection, "the boost and rpm go crazy". Boost can't climb without a load. If you place the truck in neutral and rev it up to 2500 rpm you won't get much if any boost. Less than 5psi. That's the same thing that would happen if the transmission was slipping (no load). With the same line of thinking, how does the RPM go crazy if you're pulling slowly through. And what's crazy? 10psi? 50psi? 2000rpm? 4000rpm?

Much more common would be a 2nd gear band failure. When that happens, the truck takes off from a stop like normal. Once you get to the speed at which the transmission normally shifts to second (10-28mph depending on throttle), instead of the normal shift nothing changes. The RPM just continues to climb until you let off the throttle. If you got going fast enough and you let completely off the throttle, the transmission will shift to 3rd (which works). At this point, if you ease back into the throttle the truck will slowly accelerate like normal. If, however, you give it too much throttle in 3rd at low speeds it will attempt to downshift to 2nd (which isn't there). At that point it will feel like neutral since you are actually back in 1st again.

Once you get going fast enough that the transmission won't attempt to shift back into 2nd, (above ~50mph) you can floor the truck and everything seems perfectly normal.

Does that sound like what you are experiencing? If so that's the most common failure I see from these transmissions, and to repair it you have to pull the transmission and rebuild it.

You'll need a valvebody upgrade to strengthen the transmission and prevent this from happening again. An aftermarket torque converter is significantly stronger than stock, but will add to your heating problems after an hour in stop and go traffic. An input shaft is optional but always recommended simply due to how often they break and the amount of damage it causes when they do. They typically ruin the torque converter and the front pump when they go.

We build our valvebodies to shift smoother into gear and lockup when a stock input shaft is used to minimize excessive torsional spikes to help prolong the life of the shaft.

If there's anything else I can do, let me know.