3.9 EFI tickover

[Lightbulb]

I have noticed that my 91 3.9 EFI ticks over such that when the auto box lever is moved from P to D, or R, there is a bit of a clonk and the RR wants to move off, having to be held on the brakes. Is that normal?

The tickover seems to be about 700rpm, being used to 4 pot motors this sounds high to me, but seems to accord with the Haynes manual?

Also, when I get to the point where the box changes from 1st to 2nd, there is a noticeable lurch rather than the barely perceptible change of revs when going 2nd to 3rd, 3rd to 4th. Is that OK or a sympton of problems to come?

Yours worriedly,
Andy Wells.

[Alan H]

Lurch eh?
Well, what happens is that there is some play in your transmission. You will have to have a look underneath and with wheels chocked and gearbox in neautral (not "P" where the transmission is locked) try to find where the movement is. Could be prop joints/gearbox/axle driveshafts etc. etc.
Check that everywhere has the correct type and amount of oil in and the prop joints and UJs are greased.
700rpm is a nice tickover and when you go from P to R you are asking the transmission to go the opposite way to the last time it moved (unless you were parking), then to D which makes it go the original way. This means that any play in the transmission, in effect goes backwards and forwards and clonks as drive (and system slack) is taken up. The torque converter the will convert the power of the engine on tickover to motion and creep you when in anything other than P or N. I would suggest going to a local auto specialist and getting them to do a service on your gearbox - ol & filters - and the transmission will have an easier life.
Of course, you could always think "Bolox to it" and just turn up the stereo!
Isn't kickdown lovely! Brrrrmmmmwaaaaaaaaaaaaaa!