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2-3 BIND UP SHIFT

AT Diesel Transmission Technology ( DTT ) we design and engineer transmission products for the 47RH and 47RE transmissions with Longevity & Durability in mind without sacrificing drivability.

Since Chrysler themselves created a 2-3 bind up shift in their OEM transmissions to provide better drivability (notice the key word is drivability) NOT DURABILITY, DTT had to modify & strengthen the OEM transmission to increase durability and still provide the drivability the
DTT equipped trucks are so famous for.

A lot of engineering, time and money was spent designing the DTT 2nd gear system to enhance the longevity of the Chrysler transmission and address the Chrysler 2-3 bind up shifting issues.

To understand the significance of the DTT components you must first understand the Chrysler parts and their functions.

Chrysler accomplishes the 2-3 bind up shift based on the volume of oil. It takes less volume of oil to apply 3rd gear clutches. It takes more volume of oil to release 2nd gear. So the third gear clutches have already come on before the 2nd gear band is completely released. The result is your 2-3 bind up shift. ( this means both gears are on at the same time ) .

All of the above information I have provided can be verified from your Chrysler service manuals.

On the other hand if an exaggerated 2-3 bind up shift is created by someone not familiar with the inner workings of this transmission it can shorten the transmission life. That in essence is my battle with some of the after market transmission cmpanies in the diesel industry.

2-3 Bind up for those that know how can be measured not only in terms of pressure but also in terms of time.

Anyone that knows how to cc volume a head can also prove that a 2-3 bind up shift occurs in the Chrysler transmissions.

DTT’s 3rd gear Billet Piston is another special component designed to deal with the 2-3 bind up. The DTT piston was engineered to allow the 2nd gear band to release before the 3rd gear clutch comes on.



In simple terms DTT changed the volume. We did it for 3 reasons. Have a look at the OEM piston below, see how the one side of the piston is all scuffed up while the other side does not have a mark on it.




Upon closer examination of the front drum you will notice the OEM factory front drum only has a feed slot on one side which causes the OEM factory piston to tilt during the apply cycle.



So in essesce the DTT piston & pressure plate serves 3 purposes.



1-DTT’s Billet Pistons & pressure plate changes the front clutch packs from 4 to 5 frictions.

2-DTT’s Piston & pressure plate lifts evenly thereby reducing the amount of leakage over time that the OEM factory piston produces.

3-DTT’S Billet Piston and pressure plate is part of the DTT system designed to help address the 2-3 bind up issue.

You guys may have noticed that I said the DTT piston is only part of the overrall system that we have developed to help address the 2-3 bind up.

All DTT’s custom built transmissions also include the following :

DTT’s 2nd gear servo release spring.

DTT’s custom transmission case orifices.

DTT’s 4.4 ratio apply lever for the 2nd gear band.

DTT transmission builders also use specially designed tools made for them to set clearances and tolerances within the 3rd gear clutch pack (front drum).

The OEM specifications for the front clutch pack clearance is
0 .070in - 0 .129in.

Chrysler’s variations of tolerances may also explain why one OEM transmission lasts longer than another.

You have 0.059in. + or – right from Chrysler.

With the DTT custom tooling and our Billet Piston & pressure plate system [b]DTT’s tolerances for the same clutch pack is 0.006 in. [/b]

DTT DEALERS and selected transmission shops world wide are specially trained and must adhere to DTT specifications as set out by Bill Kondolay . There is no personal interpretation allowed. At Diesel Transmission Technology ( DTT ) we know that you are paying for professional results and believe you should get professional work done by qualified builders.

The other part of the system is the valve body itself. Manipulating the governor circuit or the throttle circuit can still affect the 2-3 bind up shift
even with all the safety precautions we take .

When you are dealing with a throttle valve and the governor circuit you are now dealing with time. The time it takes to complete the shift is dependent on the amount of throttle pressure or governor pressure. Pascal’s law governs all this.

When guys start messing around with throttle pressure or governor pressure variation of even 2 or 3 psi in the wrong direction it can cause the shift valve to momentarily stop its motion dramatically shortening the life of the transmission.

The mass of these Dodge Diesels prevents the average consumer from feeling this bind up. That is why pressure testing and proper diagnostic proceedures is imperative .

Remember, just because you cannot feel bind up does not mean it is not there.


Bill Kondolay