1991 bronco E4OD problems

[Thumper22866]

I have a 1991 FrankenBronco (3 different years to make 1), the ECM, tranny, wiring harness, dash are from the 91, rear differential and transfer case from 1988., and the gears have been changed to 4.56. While driving 20-35 mph the tranny will drop gears or slip into neutral, once I reach 45-50 MPH the tranny will shift normal and will not drop gears until I slow down to that 20-35 mph range. I have replaced the sensor on the driver side of the tranny with the new upgraded harness and the problem still persists. I have no engine lights on however there is an ABS light on.

 

[miesk5]

yo,

Test the ABS system first;

RABS Self Test; except 93-96;

RABS Self Test Diagnostic Connector Location pic in a 90; "...It comes out of a large loom under the dash, coming through the firewall, near the parking brake. On mine there are 2 similar connectors in that area, the correct one has only 1 black & orange wire running to it, & was hidden on top of the loom..."



Source: by ElKabong (Ken, El Kabong) at SuperMotors.net

or it may be under glove box;

RABS Self Test Diagnostic Connector Location pic in a 92; under glove box

Source: by Jeremy M (Big '92, jermil01) at http://www.supermotors.net/registry/2896/70779

post Code(s) here;

Next, Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19

http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.

Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:

KOEO

&

KOER

----------------

--------------

Is this the sensor you replaced?

Vehicle Speed Sensor (VSS) Location pic in a 90 (at transfer case); "...The speedo gear is retained by a c-clip, visible just under my fingers here..."Steve83 wrote, "...Its magnets & tone ring are all inside that sensor body. The plastic gear drives the sensor's shaft, and that shaft drives the speedo cable. Pull the C-clip off the gear and then pull the gear off the sensor. it makes 6 pulses per rev..."

Source: by Keith L (TTB Blows, Bling-Bling) at http://www.supermotors.net/clubs/superford/registry/139/13464

Test the Manual Lever Position/Transmission Range (MLPS/TR) Sensor

Testing



Source: by SeattleFSB (Seattle FSB) at SuperMotors.net