allenman (Login allenman) Posted Nov 11, 2010 12:33 AM
The reason Mac is asking Drive vs Low is how the trans operates.
In "D", 1st gear only uses the forward clutch and the one-way roller clutch.
In "1", 1st gear adds the low-reverse band as well.
The fact that you lost 1st in "D" hints at the one-way clutch.
The fact that you lost R also hints at another problem "rev-high" clutch is bad also.
This second case would mean you would not get high gear either.
So, what to do? Best thing right now is to pull the pan and start inspecting. Pull the valve body off and perform the factory air test -- that will reveal a lot about the sealing of the rings/seals and how well the clutch packs/servos are working.