1991 Lexus LS Transmission Problem

When it is in park, is there still a load on the engine? Has the check engine light come on? When driving forward, does the trans work properly?

I don't know what you mean by load on the engine but it idles normally when in park. No engine lights on, tranny works properly when driving forward.
Can you explain what "linkage adjusting" is? Someone told that could be the issue. Or what problem am I facing? It wants to go forward in every gear except park.
Thank you.

As far as linkage, there is a cable attached to the shifter inside the vehicle. When you select different gears, the linkage (cable) moves a mechanism on the transmission to adjust for that gear. If the linkage is not adjusted properly, it won't shift to the proper gear. However, since the reverse is in a position before drive on the transmission, that means you would have to bypass it and that doesn't make sense (plus park works).

As far as a load on the engine, what I mean is does it feel like it is still trying to go forward when it is in park. If you press the gas, does the engine rev normally and freely?

One other question, the gear indicator in the vehicle, is it showing the proper gear when you shift through them?