Allison WTEC III & Gen 4 / 5 Hardware Differences

Allison WTEC III & Gen 4 / 5 Hardware Differences

 

Facts:

WTEC I,II,&III series – Late 1990’s discontinued after Gen 4 around 2006
Gen 4 – July 2005
Gen 5 – December 2012
GM sold Allison – August 2007 for 5.6 billion.
Allison 1000/2000 are the Chevy/GMC Duramax that are light duty transmissions.
Allison 3000/4000 are the medium and heavy duty transmissions used in transit buses.
⇒All of the Gen 4 and up Allison transmissions use the same TCM.
Allison DOC will troubleshoot all versions of Allison transmissions.
Allison Gen 4 / 5 require an electrical break out box to troubleshoot transmissions.
⇒The difference between Gen 4 / 5 is a newer style TCM and Shifter, mechanically same.
⇒Latest Version is Allison DOC 14.0

 

 


 

 

Specs:

 B400R                 3000 Series
B = Bus / R = Retarder
This Transmission is mainly used in 35 ft, 40ft, and 45 ft. buses. The retarder is a hydraulic
braking system used to help slow the bus down to save on brake wear.

 

Versions:
WTEC III (Discontinued, but service and parts are available)
Gen 4
Gen 5

 

⇒Weight: 700 lbs.
⇒2” shallow sump
⇒26 quarts total (excluding external components)
⇒16 quarts service fill (drain and filters)
⇒Torque converter ratio –  4:18

 


Transmission Ratios
1st – Range: 3.49 : 1
2nd – Range: 1.86 : 1
3rd – Range:  1.41 : 1
4th – Range:  1 : 1
5th – Range:  0.75 : 1
6th – Range:  0.65 : 1
Reverse – 5.03 : 1

 

 

Transmission Identification (TID)
WTEC III: TID 3

Gen 4: TID A
Gen 5: TID A
Note: ECU/TCM TID must match transmission harness TID to operate.

 

 

B500R                  4000 Series
B = Bus / R = Retarder

This Transmission is mainly used in 60 ft. articulated buses. The retarder is a hydraulic
braking system used to help slow the bus down to save on brake wear.

 

⇒Weight: 950 lbs.
⇒2” shallow sump
⇒43 quarts total (excluding external components)
⇒30 quarts service fill (drain and filters)
⇒Torque converter ratio –  5:21

 

Versions:
WTEC III (Discontinued, but service and parts are available)
Gen 4
Gen 5


Transmission Ratios
1st Range: 3.51 : 1
2nd Range: 1.91 : 1
3rd Range:  1.43 : 1
4th Range:  1 : 1
5th Range:  0.74 : 1
6th Range:  0.64 : 1
Reverse:   -4.80 : 1

 


Transmission Identification (TID)
WTEC III: TID 3

Gen 4: TID A
Gen 5: TID A
Note: ECU/TCM TID must match transmission harness TID to operate.

 

 


Clutch Combinations and Planetaries:
B400R / B500R
WTEC III, Gen 4 and Gen 5 all have the same clutch combinations. They all also use three planetaries P1, P2 and P3.
Allison, B400R, B500R
Allison B400R / B500R Cut Away


Note: B400R and B500R have the same layout for clutches and planetaries.

Neutral:       C5
Reverse:     C3 – C5
1st Range:  C1 – C5
2nd Range: C1 – C4
Lock Up =   LU
2nd Range: C1 – C4 – LU
3rd Range: C1 – C3– LU
4th Range: C1 – C2– LU
5th Range: C3 – C2– LU
6th Range: C4 – C2– LU

 


Solenoid to Clutch:
B400R / B500R
WTEC III and Gen 4 / 5 have different solenoid to clutch combinations and the shift valve bodies are completely different.

Allison, WTEC III Valve body
Allison WTEC III Solenoid to Clutch Combinations
Allison, Gen4, Gen5, Valve body
Allison Gen 4 / 5 Solenoid to Clutch Combination

ECU / TCM Types:
Allison ECU / TCM types vary with models. Verify ECU / TCM by checking the Calibration Identification Number (CIN) on the ECU / TCM tag to match the unit being replaced. If tag is missing or damaged, connecting the ECU / TCM to Allison DOC software will display the CIN number. Verifying the CIN number is the best way to assure the correct ECU / TCM is being installed into the vehicle, since mix up do occur.
Allison, WTEC III, Gen 4, Gen 5, ECU, TCM
Allison ECU / TCM Types

 

Allison DOC CIN Numbers Identify Program in ECU / TCM
Allison DOC CIN Numbers Identify Program in ECU / TCM

 

 


Allison Shifters:

Allison shifters completely differ between WTEC III and Gen 4 / 5, and are not interchangeable between versions. Gen 4 / 5 shifters are interchangeable between those two versions.

Allison, Shifter, WTEC III, Gen 4, Gen 5
Allison Shifters

 

 


Allison Valve Bodies:

Allison valve bodies between WTEC III and Gen 4 / 5 differ greatly in electronics and hydraulic flows.

Allison, B400R, WTEC III, Valve body
Allison B400R WTEC III Valve Body

 

allison, B400R, Gen 4, Gen 5, Valve body
Allison B400R Gen 4 / 5

 

Allison, WTEC III, Valve body
Allison B500R WTEC III

 

Allison, Gen 4, Gen 5, Valve body
Allison B500R Gen 4 / 5

 

 


Allison B400R Integrated Cooler:

Allison B400R Gen 5 has an option to have a bolt on integrated cooler rather than a remotely mounted unit.

Allison, Oil Cooler
Allison B400R Integrated Oil Cooler

 

 


Resource Links:

Helpful resource links –
http://bustekhub.com/index.php/2016/08/02/allison-transmission-shifter-functions-and-prognostics/
http://bustekhub.com/index.php/2016/08/13/allison-transmission-filter-oil-change-b400r-b500r/
http://www.allisontransmission.com/

https://www.youtube.com/watch?v=RiMRytjuQLw

 

7 Comments on “Allison WTEC III & Gen 4 / 5 Hardware Differences

  1. Yes I have a B400R an I’m trying to use it in a wrecker to pit with. I want to convert it to a manual. Can I change the valve body to a manual??

    1. Hey Chris,
      I really had to give this one some thought. I think what your asking is to have a stand alone transmission (no ECU) and be able to shift the transmission. The only way I see to do this, is to energize the transmission solenoids manually. In other words, you would send electrical power to energize the solenoids that would give you 1st gear or power the solenoids to engage reverse. Let me know if this is what your trying to do and I could elaborate more on it. To make it a full manual would require extreme modifications to the valve body.
      Thanks and Cheers from BusTekHub.com

  2. Uen dia compañeros y amigos..pregunta si fan asesorias o algo por el estilo yengo un problema con una b500r wtec111 se los agradesere si hay alguna ayuda ..my falla es que solo meto cambio y se apaga el camion ,como si engranara el clutch de la turbina, y no deja avanzar para checar los demas cambios,.muchas gracias

    1. Hola,
      el problema va ser el “lock up” clutch. En el cuerpo de valvulas solenoid “F”, la valvula que controla el “lock up” va estar atorada. Esto ace que la turbina y la bomba del convertidor esten mecanicamente conectadas y apaga el motor. Hay que bajar el cuerpo de valvulas y sacar el solenoid “F” para inspeccionar la valvula si esta atorada. Inspectiona esta valvula del “lock up”.

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