A/T - Slips, Improper Operation/Shifting

Classification: AT94-001a

Section: Automatic Transmission

Models: 1991-93 Sentra

Reference: TECHNICAL BULLETIN NTB94-OO6a

Date: November 29, 1994

1991-93 SENTRA (B13) IMPROPER OPERATION OF F03A AUTOMATIC TRANSMISSION

NOTE:
This is a revised Technical Bulletin presenting additional diagnostic information. Please discard your original copy of NTB94-006 (AT94-OO1).

APPLIED MODELS
1991-93 Sentra (B13) with FO3A (4 speed A/T)

APPLIED C/M DATE
February 1993

SERVICE INFORMATION

This bulletin applies if a 1991-93 Sentra exhibits one or more of the following symptoms:

^ Automatic transmission downshifts from 3rd gear to 2nd gear and will not upshift back to 3rd gear.

^ Automatic transmission will not upshift to 3rd gear on normal acceleration.

^ Automatic transmission will not upshift from 3rd gear to 4th gear. Shift shock from "N" to "D".

^ Automatic transmission slips, poor acceleration.

NOTE:
Automatic transmission operation is normal until engine reaches operating temperature of 95°C (180°F).


SERVICE PROCEDURE

Some of these symptoms may be caused by a burnt High Clutch or a sticking Control Valve Assembly. Debris from the burnt High Clutch may have gotten into the Control Valve Assembly, causing it to stick. The shape of the oil feed hole on the oil pump housing has been modified, allowing oil to enter more easily. This improves oil flow and lubrication, preventing a burnt High Clutch.

1. Replace the damaged High Clutch as an Assembly (refer to the appropriate Parts Microfiche for the correct part number with respect to vehicle production date).

2. When repairing the automatic transmission on a 1991-93 Sentra (B13), the Control Valve Body should be cleaned and thoroughly inspected for wear on individual valves and Control Valve Body bores. If wear is noted, repair or replace as necessary.