NUMBER: 21-001-10 REV. A
GROUP: Transmission
DATE: April 20, 2010
SUBJECT:
Manual Transmission Pops Out of Gear
OVERVIEW:
This bulletin involves verifying that the transmission shift boot is not interfering with the engagement of first gear and if not than, replace the first gear and 1-2 synchronizer assembly.
MODELS:
| 2007 – 2010 | KA/KK | Nitro/Liberty |
| 2007 – 2010 | JK | Wrangler |
NOTE: This bulletin applies to vehicles equipped with a manual transmission (sales code DEH).
SYMPTOM/CONDITION:
The transmission pops out of first gear while accelerating. The condition, may occur intermittently and may be difficult to diagnose.
DIAGNOSIS:
Verify that the shift boot is not causing the issue by ensuring the boot is not binding when in first gear. In addition, if the customer complains that the transmission pops out of gear in first, third, and fifth, than the shift boot would be most likely the cause for the complaint. Refer to the appropriate service information regarding shift boot replacement. If the shift boot is not causing the transmission to pop out of first gear, perform the following Repair Procedure.
PARTS REQUIRED:
| Qty. | Part No. | Description |
|---|---|---|
| 1 | 68080512AB | Kit, First Gear and 1-2 Synchronizer Assembly –
INTERNATIONAL ONLY |
| 1 | 68085902AA | Kit, First Gear and 1-2 Synchronizer Assembly –
NAFTA/LATIN AMERICA ONLY |
| 2 | 04874464
Genuine Mopar Fluid 4874464 Manual Transmission Lubricant - 1 Quart
Last update on 2026-06-19 / Affiliate links / Images from Amazon Product Advertising API | Lubricant, Manual Transmission |
| AR (1) | 04318083 No products found. | Gasket Maker |
/Mopar factory fit part
SPECIAL TOOLS/EQUIPMENT REQUIRED:
| 9633 | NSG370 Manual Transmission Build Fixture |
| 9636 | Mainshaft/Bearing Remover |
| 9648 | Mainshaft Build Fixture |
| 8228 | 1-2 Synchronizer Hub Installer |
| W-262 | Reverse Gear Synchronizer Hub Installer |
| Standard Three Jaw Gear Puller | |
| Bearing Heater/Hot Plate |
REPAIR PROCEDURE:
- Remove the transmission from the vehicle. Follow the procedures identified in DealerCONNECT>TechCONNECT>Service Info>21 – Transmission and Transfer Case>Manual, NSG370>Disassembly>Disassembly.
- Disassemble the transmission. Follow the procedures identified in DealerCONNECT>TechCONNECT>Service Info>21 – Transmission and Transfer Case>Manual, NSG370>Disassembly>Disassembly.
- Install the new first gear and the 1-2 synchronizer assembly (from kit p/n 68080512AB – INTERNATIONAL ONLY or p/n 68085902AA – NAFTA/LATIN AMERICA ONLY) onto the mainshaft. Follow the procedures identified in DealerCONNECT>TechCONNECT>Service Info>21 – Transmission and Transfer Case>Manual, NSG370>Assembly>Assembly.
NOTE: When installing the synchronizer sleeve, make sure that the side of the sleeve with the groove faces toward second gear.
NOTE: The selective snap rings are made available in case the mainshaft snap ring is damaged when disassembling the shaft. Upon reassembly, select the thickest snap ring that will fit properly in the snap ring groove.
- Then, reassemble the transmission using the new front countershaft seal and output shaft seal (from kit p/n 68080512AB – INTERNATIONAL ONLY or p/n 68085902AA NAFTA/LATIN AMERICA ONLY).
- Install the transmission into the vehicle. Follow the procedures identified in DealerCONNECT>TechCONNECT>Service Info>21 – Transmission and Transfer Case>Manual, NSG370>Installation>Installation.
- Fill the transmission with 1.5 L (3.17 pts.) of Mopar Manual Transmission Lubricant (p/n 04874464).
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
| Labor Operation No: | Description | Amount |
| 21-00-11-90 | Transmission, Install 1-2 Synchronizer Assembly – 4X4 Only (B). | 5.4 Hrs. |
| 21-00-11-92 | Transmission, Install 1-2 Synchronizer Assembly – 4X2 Only (B). | 4.2 Hrs. |
FAILURE CODE:
| ZZ | Service Action |
THIS BULLETIN IS BEING PROVIDED IN ADVANCE. PARTS ARE NOT EXPECTED TO BE AVAILABLE UNTIL APRIL 23, 2010. UNLESS THERE IS AN IMMEDIATE NEED, DO NOT ORDER PARTS UNTIL APRIL 23, 2010. ALL ORDERS WILL BE HELD UNTIL STOCK IS ON HAND.
THIS BULLETIN SUPERSEDES SERVICE BULLETIN 21-001-10, DATED MARCH 2, 2010, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH **ASTERISKS** AND INCLUDE NEW PART NUMBERS FOR THE FIRST GEAR AND 1-2 SYNCHRONIZER KIT AND A REVISION TO THE 4X2 LABOR OPERATION NUMBER.
- HIGH PERFORMANCE - gear protection and longer synchro life. Recommended for GL-1, GL-3, and GL-4 applications.
- QUICKER SHIFTS - perfect synchronizer coefficient of friction and eliminates notchy shifting, even when cold
- REQUIREMENTS - gear oil viscosity of 75W; 80W; SAE 40 10W40 and 15W40 motor oil
- POPULAR GEAR OIL FOR - GL-1, GL-3 and GL-4 applications, as well as where most special synchromesh fluids are specified. Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
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