Targa shifts worse as fuel depletes

[schoward]

Did a search and did not see anything on this phenomenon....

Have noticed more and more that my 81SC Targa shifts worse and worse as i burn through a tank of gas. Fill the tank and shifting is great again. My 915 box was refreshed about 5 years ago and no known issues.

No lie - fuel level seems to directly affect shifting. When I go from near empty and fill the tank, first (and subsequent shifts out of the gas station are very noticably smoother. Below 1/2 a tank - shifting routinely gets more balky and seeming like something is out of alignment.

Targa Flex issue? Does full fuel tank weight do something to stiffen or stabilize chassis? Car is pretty much bone stock. Is this indicative of something else (shift bushings?).

I do have fairly recent sport mounts on both engine and trans. I removed rear tunnel cover and coupler bushings looked decent. Havent checked ball cup bushing.

Any ideas, experiences or thoughts?

Thanks in advance.

[Hugh R]

I'd go through your shifter and linkage bushings

[dtxscott]

Also look at engine and trans mounts.... Worn mounts can cause poor shifting.