Has anyone ever heard of a 4T65E-HD with a 3.05 final drive ratio?

If so, exactly which model(*) / year(*) was it available on?

Never. The 3.05 was available only on mid-level Bonneville'* and Olds 88/LSS'*, top of the line Lesabres, LS model Regals, Chevrolet Impala'*, Monte Carlo'* and mid-level Park Avenue'*. I can't think of any other cars that it came with, but there were ZERO 4T65E-HD'* with the 3.05 gear ratio.

You could probably make one swaping the sun gear and planetary pinion gears from the 3.05 diff into the 3.29 HD diff.

Never heard of a 3.05 HD tranny as a stock option though.

That was my next thought. In my mind, I don't see that as possible, though.

I know they all use the same outer ring gear (78 tooth fine pitch). I know the sungears have different tooth counts (34 for 3.29, 38 for 3.05), from which I would assume they are different diameters, and that the planetaries would therefore have to be different diameters also.

If this is so, then I don't see how the shafts for the planetaries could be the same size and/or in the same location on the carrier...I would think these shafts on the 3.05 would have to be either drilled further from center or be a smaller diameter than on the 3.29.

I've got a 3.29 HD diff sitting here. I may have to scrounge up a 3.05 non-HD diff to see if this is possible.