98 Vs 94 4L60E

[Len Sabatine]

     Dale,
     95 and up PCMs read and adjust line pressure per Map -Tps +  referred 
as T.A.P. 95 and up pumps show  "PWM" letters on front of pump casting.
     Non "PWM" pump will fit , however the Pressure control circuit is then 
disabled which flags a DTC 73 in OBD1 .
   95 and up also have  additional  VB solenoid for this pressure control 
routine along with a "feed back loop "and added code for A4
     Software. Can't remember exactly , later down stream TCC Apply is also 
involved with PWM as well. All depends on MY and Vehicle specific features.
     All this "boils down" to Transmission Adaptive Pressure Modifiers. 
They can get in the way @ Drag Strip. Mixing SW Code and HW can produce a
     Screen full of  DTCs or POs . FWIW.
     Len

>Do you mean PWM for line pressure control from ecm (as opposed to throttle 
>valve pressure control), or pwm for TCC lockup?  What would be different 
>about the pump?, wouldn't the pump be the same, the difference would be 
>how the pump control pressure gets generated (and thus the probably 
>different connectors)?
>Thanks, Just curious....        Dale
>
>At 09:43 PM 2/25/01 -0500, you wrote:
>>       Might want to check if 94 4L60E has PWM Pump , 98 has it , OBD2 PCM
>>       will be looking for it. If 94 is sans , Install later PWM Pump and 
>> change the
>>       internal harness and connector. Trans control harness from 94 PCM 
>> will be
>>       missing the required extra wire[s]. Ya just need to compare what 
>> you have
>>       against the 98. Most 95 and later 4L60Es are PWM, Most 94 and earlier
>>       are not. The 98 trans should have  a bolt on bell housing , your 
>> 94 may not.
>>       Compare all functions from the 98 to your 94 , avoids problems 
>> later.You'll
>>       need longer Selector- Detent  shaft to utilize the external PRNDL 
>> / BackUp
>>       Light switch module and the needed Metri Pack connectors.If you 
>> get the 98
>>       Trans, get torque converter with it.   FYI.
>>       Len
>>
>>>I need a quick answer on this one. I have some manuals on the way but I
>>>don't think they'll get here in time. I currently have a 94 TBI 5.7L w/
>>>4L60E setup. I have found a good deal on a 98 model Vortec 5.7L that
>>>originally had a 4L60E as well. I want to remove the TBI motor and drop in
>>>the Vortec. I need to know if the VCM from a 98 C1500 w/5.7L & 4L60E tranny
>>>will work with a similar 94 model 4L60E.  I know the '98 4L60E has a PRNDL
>>>switch and my 94 does not. My 94 does have the bosses on the tranny for it
>>>though. I will install the PRNDL switch on the '94. I just want to double
>>>check and make sure they didn't change the location of any wires within the
>>>wiring harness plug at the tranny etc. I can scan in the 94 model diagram
>>>from the manual if anyone has a newer manual to compare with. I just need to
>>>know if this will work before I buy the engine.
>>>Thanks
>>>Paul Washburn
>>>lpwcruzr at sysmatrix.net
>>>
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>
>
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