THM 4L80-E/4L80-EHD - Rear Lube Seal And Orifice Location

ATSG recieves many phone calls wanting to know the location of the Orificed Cup Plug Lube Seal for the THM 4L80-E transmission. We have shown the location of this orificed cup plug and seal assembly in Figure 1. Lube oil is fed through this orificed cup plug and into a passage in the extension housing that leads to the extension housing bushing, to lubricate the bushing.

Since four wheel drive models do not have an extension housing bushing to lubricate, there will be a solid cup plug in this location on all four wheel drive models.   Extra caution must be used if you happen to be changing the transmission case.   If a four wheel drive case (Solid Plug) were to be installed with a two wheel drive output shaft and extension housing, the bushing would be gone in a very short period of time.

Always inspect and replace the Orificed Cup Plug Lube Seal on 2WD trucks as shown in Figure 1. So know more hot car tools Volvo Vida Dice and Carprog Full?