Exhaust brake in an auto???

[Dkevdog]

OK- Here I go again with another on of those questions. I have noticed that some of the exhaust brakes out there can not be installed on a Ram with an auto. Are there any out there that can? Why or why not? My wife drives transit (type 1 buses) and many of them have Exhaust brakes (retarders as she calls 'em) and all of them are autos. Forgive my ignorance but I had to ask.



Kev

 

[ACoyle]

The RAM with an Auto trans has a heat problem due to fluid shear. In other words, when you let off the torque converter unlocks. If you use an engine brake, which needs higher RPM, you will increase fluid shear and heat. You cook the trans.



Some of us have installed "Mystery Switches" which keep the Torque converter form unlocking. This helps with fluid shear, however, it agrivates another problem. The clutch in the Torque converter is small and can how slip under heavy braking. The converter then wears out fast and has to be replaced.



There are devices available to increase line pressure, which holds the clutch harder in theory hoping that it will slip less.



The real answer - You need ot replace the torque converter and valve body in your trans with uprated units.



That's about as generic as it gets witheout just telling you to call Bikk K. at DTT. He can explain it a lot better.

 

[Joe G.]

Actually, the exhaust brake does not work without some way to lock the TCC. The engine just drops to idle and you go down the hill in what amounts to free wheel. I used a manual lock up switch (mystery switch) for quite some time with a stock TC but I didn't hot rod it or pull my TT with the TCC locked up. The switch works fine but you can tear up your TCC if you don't pay attention to what you are doing. Bill K's smart TC controller is the way to go if you are going to use an exhaust brake.

 

[Archive]

In fact... Dodge made a deal with Cummins about a year or so ago to "buy-back" all of the Cummins e-brakes that were sold/installed on autos. Dodge had no leverage on the other brake companies.

 

[JohnMcIntyre]

From the horse's mouth!!

Originally posted by Dkevdog

OK- Here I go again with another on of those questions. I have noticed that some of the exhaust brakes out there can not be installed on a Ram with an auto. Are there any out there that can? Kev

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Actually Kev, the installation of most any exhaust brake on any Dodge truck either with or without auto transmission is not the limiting factor. In standard form, it is as much use as a f*rt in a thunderstorm, without some sort of lockup which can be kicked out, ideally automatically when the speed drops below a certain threshold. Do yourself a favour and give Bill K a call.