There is a tech bulliten for two wheel drive trucks, heres the meat of it.
4R70W - DRIVELINE VIBRATION - FLUID LEAK FROM EXTENSION HOUSING SEAL TECHNICAL SERVICE BULLETIN Reference Number(s): 01-9-3, Date of Issue: May 14, 2001 Superceded Bulletin(s): 99-26-2, Date of Issue: December 27, 1999 Related Ref Number(s): 01-9-3, 99-26-2 ARTICLE BEGINNING VIBRATION - FROM DRIVELINE - 4X2 VEHICLES WITH 4R70W AND 139 INCH WHEELBASE TRANSMISSION - 4R70W - FLUID LEAK FROM EXTENSION HOUSING SEAL - 4X2 VEHICLES WITH 139 INCH WHEELBASE Model(s): Ford: 1997-2000 F-150, F-250 LD Bulletin No.: 01-9-3 Date: May 14, 2001 99-26-2 dated December 27, 1999 99-24-1 dated November 29, 1999 ISSUE A driveline vibration and/or a transmission fluid leak from the extension housing seal area may occur on some vehicles. This may be caused by the extension housing bushing or seal walking/spinning out due to excess driveshaft flexing during extended high speed operation. ACTION Inspect the extension housing bushing and seal. If the extension bushing/seal is spun and/or walked out, replace the extension housing assembly and gasket with new service parts, and replace the driveshaft with a revised 127mm (5") diameter driveshaft. In addition, some vehicles will require the balance marks on the driveshaft, output shaft, and rear axle flange to: be aligned so a repeat condition will not occur. Refer to the following Service Procedure for details. SERVICE PROCEDURE 1. Raise the vehicle on a hoist and inspect the transmission extension housing bushing and seal for damage. In addition, inspect the driveshaft diameter. The revised driveshaft has a 127mm (5") diameter and the old part has a 114mm (4.5") diameter. 2. If the extension housing bushing or seal is damaged, remove the driveshaft and transmission extension housing per the appropriate year Workshop Manual, Section 307-01. Install a new NOTE: This bulletin supersedes the following Technical Service Bulletins: Extension Housing Assembly (F3LY-7A039-A), and a new Extension Housing Gasket (F6AZ- 7086-A). Verify transmission fluid level. 3. If the vehicle is equipped with the 114mm (4.5") aluminum driveshaft, replace the driveshaft with the revised 127mm (5") Driveshaft (see parts list for application). NOTE: On vehicles built after 4/1/1998, the index paint marks on the output shaft, driveshaft, and rear axle must be aligned. The indexed balance mark on the output shaft and the indexed balance mark on the new driveshaft yoke must be aligned (Fig. 1 ). Alignment of the index marks on the rear driveshaft tube and the rear axle flange must be performed (Fig. 2 ).
Sunday, March 14th, 2010 AT 7:54 AM