Hi All,

I'm scared as a little girl at the moment... I've just changed Idle Valve with stepper motor and O2sensor at my garage, due to rough idle and stalling. All well for about a week, until this evening. Now I have a scary noise in the auto gearbox of my -89 3.6.

1.
It's cold in Norway these days, about -2 Celsius. When I cold start car it idles fine - about 700 rpm, but when engine runs warm it idles to 1400 rpm at standstill, before reducing to 900 rpm at other times, and goes back and forth between 900-1400 rpms. Whit no acc. pedal pressure the car "runs forward" due to the high rpm and I have to apply quite some brake preassure to stand still at traffic lights.

2.
When I put car from "park" to "drive" i get this grinding noise, almost like something is loose or cogs grinding. The sound is only present at "reverse" and "drive", but quiets down at "park" and "neutral". AT fluid seems Ok, measured with hot engine running in "Neutral". It's hard to read dipstick, but covered in nice red oil - no burnt smell or brown color. Car shifts fine, no sluggish changes.. (at low speeds at least, I don't dare to run car agressively...)

My question - Can this be related to wrong idle setting at garage, and will the AT behave like this with wrong idle setting? What about the scary noise in AT?

Any suggestions or tips what to look for, except adjust idle speed and order a AT oil change?

Why oh why - now when all was good....

 

Hi Harald, A bad or wrongly set IAC will make it do all sorts of strange things. I would suggest, that you firstly check, or have checked this component........Roger.

 

Sounds to me by your description like 1) the governor in your transmission is giving up 2)there are broken springs in the valve body or 3) your torque converter is on the way out.... governor and valve body are both relatively easy fix with the transmission in situ... torque converter means pulling the transmission... not a job for the faint hearted...

It might also be a case of damaged gears/drums inside the transmission itself... all worth investigating before you just go throwing new oil at it

Two good write ups on the ZF4HP22 Transmission can be found here:

http://www.rangerovers.net/repairdet...ansrepair.html

http://www.disgruntledgoat.com/conte...ar/ZF4HP22.php

 

Thanks guys,

I read myself up a little on your links, and try adjusting the idle first. Let us hope its easily solved.

Brrr... I still feel like a scared girl...;-)