Allison Rear Housing Support, Duramax | 2001-2007

The transmission rear housing on 2001-early 2007 Duramax trucks is prone to cracking from excessive driveline vibration, which is commonly caused by a failing u-joint or an improperly balanced driveshaft. The housing is heavy and is supported only by the bolts that hold it to the back of the transmission. The Merchant Automotive Rear Housing Support strengthens this area to help prevent the transmission housing from cracking. It fits 2001-early 2007 Chevy Silverado and GMC Sierra 2500HD and 3500HD 4WD trucks with the LB7, LLY or LBZ 6.6L Duramax diesel or the 8.1L gas engine and the Allison transmission.

Features

• 7/8" DOM mild steel tubing with 0.120" wall thickness
• 3/16" plate steel with the Merchant Automotive MA logo
• Bright orange finish
• Installs with basic hand tools and your factory bolts
• Made in the USA at our Holland, Michigan facility using robotic welding

What's Included

• (1) Merchant Automotive Rear Housing Support

Why Support the Rear Housing

The rear housing is heavy and is held on only by its bolts to the transmission. Driveline vibration from a worn u-joint or an out-of-balance driveshaft puts that housing under repeated stress, which can lead to cracking. The rear housing support adds support to this area to help prevent cracks, and it helps support trucks used off-road and in harsh conditions.

Before You Order

• 4WD Allison only: this support is for 4WD trucks with the Allison transmission. For trucks with the ZF6 manual transmission, see the ZF6 Rear Housing Support.
• 2001-early 2007 only: for 2007.5-2010 trucks, see the 2007.5-2010 Rear Housing Support. For 2011-2019 trucks, see the 2011-2019 Rear Housing Support.

Installation Tips

• Check the u-joints and driveshaft balance at the same time, since driveline vibration is a common cause of housing cracks.
• Inspect the rear housing for cracks or leaks before installing the support.

Installation Resources

• Installation Video
• Truck U Segment on the MA Rear Support Brace
• Two Guys Garage Segment on the MA Rear Support Brace

Related Parts

• Merchant Automotive Motor Mounts, Duramax 2001-2010
• Polyurethane Transmission Mount, Duramax 2001-2010
• Polyurethane Transmission Mount, Allison 1000, 2011-2021

Frequently Asked Questions

Does it fit 2WD trucks?
No. This support is for 4WD trucks with the Allison transmission.

Do I need new bolts?
No. It installs with basic hand tools and your factory bolts.

What else should I install with it?
We suggest our Merchant Automotive Motor Mounts and Polyurethane Transmission Mount for 2001-2010 trucks. For 2011-2016 trucks, see the Polyurethane Transmission Mount for 2011 and newer.

Will it fit my 2007.5 or newer Duramax?
No. See the 2007.5-2010 Rear Housing Support or the 2011-2019 Rear Housing Support.

For warranty information, see our Warranty Policy.