The MGB GT V8 uses an open propshaft with universal joints at each end, transmitting drive from the gearbox tail to the rear axle pinion flange. The propshaft includes a sliding spline joint that accommodates the small length variation between gearbox and axle as the rear suspension articulates. The propshaft is V8-specific in length and joint specification, matched to the V8 gearbox tail position and the tube-type rear axle pinion flange.
Universal Joints
Universal joints (UJs) at each end of the propshaft allow the shaft to transmit drive through the slight angular changes between gearbox and axle as the rear axle moves up and down with the suspension. UJs are wear items: the needle bearings inside each yoke wear over time and eventually develop excessive play, causing vibration through the drivetrain. Replacement UJs are available individually.
UJ Service
UJ replacement requires removing the propshaft from the car, pressing out the old UJ, and installing the new one. The UJ is held in each yoke by circlips at the bearing cup, with the cup pressed in or out using a press or a heavy-duty puller. UJs should be greased at installation if grease nipples are fitted, or are pre-greased if of the sealed-for-life type.
Sliding Spline Joint
The sliding spline joint at the gearbox end allows the propshaft to extend and shorten slightly as the rear axle articulates. The splined section runs in the gearbox tail bushing and should be greased at service intervals to prevent rust forming on the spline surface.
Pinion Flange and Fixings
The propshaft connects to the rear axle pinion flange via four bolts and lock-tabs. Pinion flange bolts should be torque-tightened and the lock-tabs bent over to prevent loosening in service.
Replacement bolts and lock-tabs are available individually.
MGOC Spares
MGOC Spares supplies V8 propshafts, universal joints, pinion flange bolts and all associated propshaft service components for the MGB GT V8.