The oil level is too high.

.Adjust the oil level.

Refer to Transmission Fluid Check .

The lubricant in the transmission is incorrect.

Replace the transmission oil. Refer to Fluid Capacity Specifications .

Bolts are loose or missing.

Tighten the loose bolts to the proper torque value.

Bearing cap seals are worn.

Overhaul the transmission. Refer to applicable Allison Transmission Service Manual.

The transmission breather is plugged internally.

Overhaul the transmission. Refer to applicable Allison Transmission Service Manual.

Seal plugs are loose or missing.

Replace the seal plugs.

There are worn gaskets.

Overhaul the transmission. Refer to applicable Allison Transmission Service Manual.

There are cracks in the transmission case.

Overhaul the transmission. Refer to applicable Allison Transmission Service Manual.

Drain or filter plugs are loose.

Tighten the drain or filter plugs to the proper torque.

Bearing caps are worn or plugged.

Clean or replace the bearing caps.