C4 Corvette LS Transmission Mount Adapters

BRP lists its four late model transmission mount adapters here for C4 Corvette LS swaps. Read the C4 guide first: it names the 1998-2002 F-Body T-56, the T-56 Magnum and the 4L60E, 4L65E, 4L70E and 4L75E as the only late model LS gearboxes that work with the 1984-1991 kit, and none of these adapters is made for those.

C4 kit gearboxes: T-56 and 4L60E to 4L75E
T-56 needs a shortened, drilled C-beam
Adapters for TR-6060, 6L90E, 8L90E, 10L90E

Transmission details for this car are in the 1984-1991 Corvette LS install guide. Mounts, the C-beam bracket and radiators are on the C4 Corvette LS swap parts page.

$39.99 MG9 high-torque TR-6060 Trans Mount Adapter

$39.95 Cadillac CTS-V 6L90E Transmission Mount Adapter

$39.99 Cadillac CTS-V T-56 / standard TR-6060 Trans Mount Adapter

Transmission mount adapters listed for the C4

TR-6060 manual adapters

6L90E and 8L90E / 10L90E automatic adapters

What each adapter includes

Standard TR-6060 / CTS-V T-56 adapter: 3/16 inch steel, black.
Laser cut, CNC bent and jig welded, with hardware.
MG9 TR-6060 adapter: comes with hardware.
Automatic adapters: listed for BRP transmission crossmembers.

1984-1991 Corvette transmission notes

Late model gearboxes the C4 guide approves: 1998-2002 F-Body T-56, T-56 Magnum, 4L60E, 4L65E, 4L70E and 4L75E.
A T-56 is longer, so the C-beam gets shortened and a new 1/2 inch hole, with 1/4 inch shims placed two below and one above.
The 4L60E through 4L75E need no C-beam changes. With a 4L60E, fully tighten the two upper C-beam bracket bolts through the tailshaft before the transmission goes in.
The kit puts the rear face of the block in the stock spot, so the factory ZF six speed fits with Quick Time bell housing RM6039 and a Ram throwout bearing.
A factory 700R4 bolts to the LS block with a flywheel spacer.

Notes from the 1984-1991 Corvette LS install guide.

C4 Corvette LS transmission mount adapter FAQ

Can I run a TR-6060 or 6L90E in my C4 with the BRP kit?

The C4 guide lists the 1998-2002 F-Body T-56 and T-56 Magnum plus the 4L60E, 4L65E, 4L70E and 4L75E as the only late model LS transmissions that work with the kit. The TR-6060, 6L90E and 8L90E are not on that list.

What does a T-56 change in a C4 LS swap?

The C-beam has to be shortened to make up for the longer T-56, and it needs one added 1/2 inch hole. A provided 1/4 inch spacer shim is the drilling template.

Do I need an adapter for a 4L60E in a C4?

The guide does not use one. The 4L60E family bolts to the upper and lower C-beam brackets with the supplied bolts and needs no C-beam changes.

Can I keep the factory ZF six speed?

Yes, per the guide. Use a Quick Time bell housing, part RM6039, with a Ram throwout bearing that fits it.

1984 - 1996 Corvette LS Transmission Mount Adapters