EEC Codes: 171 172 173 634. Trans was "bumping" in and out of OD at any slight incline of roadway, and, if accelerating (1-3) sometimes would "jerk" as if it couldn't make up it's mind as to what gear to be in, otherwise never felt shifting through gears. Based on suggestions in this forum and codes, had MLP Sensor replaced in a shop - Now, when shifting up through gears, feels like I'm being kicked by a mule between each gear (can't feel any shifting when slowing down). Shop says MLP "may" be bad and ordered another one, in addition shop says the 171-173 codes require an oxygen sensor replacement (another $150).

Was quoted $2K to rebuild trans, but, forum suggestions stopped this option. Is this the right route?

The truck otherwise (with 175K) runs extremely well and is in excellent condition (body & interior). No "cash for clunkers" option due to truck condition.

P.S. On the EEC, when I put the jumper on between the SIG RTN and STI and turned the key on, the CEL came on but no codes, however, when I jumped between the STI and ground, the codes flashed. This is different then the ways noted in some of the forums thus, is this procedure unique to this vehicle/year, EEC bad (although I got the same readings 2 times) or other suggestion(s)?

 

Service Code 634 indicates the MLP sensor is out of Self-Test range when the gear selector is in PARK. Correct resistance range for this sensor is from 3770 to 4607 ohms.

Possible causes:
-- Misadjusted linkage.
-- Open or short in harness circuits.
-- Damaged MLP sensor.
-- Damaged processor.

You need to check the wiring from the MLPS with an ohm meter.

Also:
Key off.
Apply parking brake.
Place transmission in NEUTRAL.
Verify that Manual Lever Position Sensor Tool (Rotunda T89T-70010-J) or equivalent fits in the appropriate slot.

Does the tool fit properly?

 

The "replacement" MLPS was defective. The re-replacement has been installed and it works like new (have taken it out on I-95, put it through the paces - acceleration, OD on/off at less than 55 mph, up inclines, etc.). Thanks for all the reviews to consider!!!

Will delete this message tomorrow, just wanted to say, "Thank You"! Bottom line - I paid myself about $190/hr for 10 hours worth of research on this website.