Another question from a newbie

[paulb2004uk]

My 406 doesnt like doing anything below 32 mph in 4th and 45 or under in 5th. Its a 2.0 hdi (90). I'm hoping that this shouldn't be the case and also hoping its not going to cast an arm or a leg to resolve. It's done 59K and was last serviced at 58.4K, any ideas

Thanks.