Hi.
My 120k 2001 4.6 gearbox sometimes is slow to engage first gear when the car is taken from park to drive. It can be 4 or 5 seconds.

I have never had this problem from park to reverse (but the problem could be there, it doesn't happen every time).

The fault occurs both when the car is just started AND when it has been idling for a few minutes.

Once the problem has occurred, it won't happen again the same day.

When it engages drive (after the faulty pause), it makes a single knock noise. Usually, it engages silently.

When working, it works well (very smooth).

The only other issue is very rare. It displays "gearbox overheat" but only in really cold weather and only within 3 minutes of starting the car for the first time (useally, before I pull away).

I'm guessing the best diagnostic route would be to change the oil and filter first? Nothing useful for me to do with the Nanocom?

Many thanks again all.

Agreed, I'd start with fluid and filter first and make sure you fill it fully as on a 2001 you don't have the dipstick tube like on the earlier cars. I came across the same problem on an Audi years ago and that was because it had been serviced and the mechanic that did it had put the wrong fluid in it.

Many thanks. Will do and update.

+1 for changing ATF and filter. Two or three changes on lightly used car with some decent miles and bit of Italian Tune up in between to get fluids nice and hot so they flow well. Hopefully shifting any odd bits floating around.

Gave the big red beast that treatment the other year after changing the cooler and I'm convinced everything snappier and just working better. First change came out a bit dirty but, realistically was probably fine, second change wasn't quite clean. So being an anal type I gave it another. What I really miss about no dipstick on the Thor cars is not being able to see what the oil actually looks like and how much grumpf its carrying round.

Opinions on a full flush to change all the oil in one go, including that left in the torque converter, seem to be divided. There is school of thought claiming its risky on an older transmission.

Clive

Many thanks Clive.
I've never messed with auto gearboxes.
Understanding that I'm only changing part (probably just over half) the oil took a while to sink in.

After an oil and filter change, let's see how much debris there is (and if the current issue resolves).

Seller made a few unsubstantiated claims about changing oil. Will post back here. Especially if I get some really nasty stuff out.