GM Service Manual Online
For 1990-2009 cars only

Object Number: 1708647  Size: MF

Power Take-Off Unit PTU Operation

The transfer case PTU in this vehicle consists of an aluminum housing and a ring and pinion power transfer system.

The PTU transfers torque/power using an active on-demand coupling built into the rear differential design via a 1-piece propshaft assembly.

The on-demand rear differential distributes variable torque/power to the rear wheels via individual axle shafts.

The on-demand system operates as follows: the control system of the coupling monitors vehicle conditions, such as vehicle speed and wheel speeds, and commands torque to the rear wheels when depending on these variables. Typical conditions when torque is applied are during vehicle launches, even without wheel slip, and when there is front wheel slippage relative to the rear wheels. The amount of torque depends on the vehicle speed and the amount of wheel slippage.

Long term durability studies show that the rock shield, not shown, is no longer required. If it was disassembled, it need not be replaced or assembled.

PTU Fluid

Important: 

   • The Sport/GXP, XL-7 Suzuki, and Saturn VUE Getrag PTU uses synthetic differential lube.
   • The Equinox and Torrent base vehicles use only GM Versatrak fluid in the PTU.
   • Due to a 2008 mid-model design update, selection of the proper front drive axle inner shaft replacement seal is critical. refer to New Product Information.

The PTU uses a specifically developed synthetic hypoid gear lubricant, which is intended for lifetime service. Full fluid level is at the bottom of the fill plug hole.