So I saw a similar issue in the disco forum after running a search. Basically when first starting my 2003 for the day and going into reverse it doesnt take, almost feels as though still in neutral. If I wait a few minutes, and go through the gears, reverse will eventually take. Also doesnt happen if I've driven somewhere and parked for a bit. I've heard of the transmission needing time to build pressure but I've never owned even an older vehicle with this issue.

I ordered 7 liters of trans fluid and a new filter to start there, but wondering if anyone else has experienced this and if I should start saving for a major transmission rebuild. TBH this car cost me only $3k so not sure how worth it it will be, but I love it, its in great shape and running very smooth so I'd consider putting money into it.

Any help would be greatly appreciated, thanks!