Help please :)

[heno]

Hi There,

Have been everywhere trying to find an answer but nothing yet.

I have a VT, all stock, 1999. Just a runabout to and from work.

Has an automatic transmission.

In the 2 high gears, at low revs, there is a low pitched hum or growl and a slight vibration coming from the engine.

It kicks in at 53kmph and 1000rpm and leaves at 58kmph / 1250rpm and also comes again at 76kmph / 1000rpm and leaves at 80kmph / 1250rpm.

If you accelerate smoothly up to 85 then it does not happen at all. Only happens when you gradually get up to cruising speeds and as it drops into the next gear, it happens.

Does not happen at all in first 2 gears. Does not seem to affect performance at all.

Any help would be great!

 

[dirty hands]

so you are only worried about engine noise that comes and goes
and you say the tranny is all good

the problem
low pitched hum or growl and a slight vibration coming from the engine.

rules out a lot of things I was thinking of when you accelerate smoothly
If you accelerate smoothly up to 85 then it does not happen at all.

I would start with anything on the serp belt

water pump -powersteering - aircon-alternator tensioners etc

check engine mounts

 

[billythakid]

Could be anything
Tyres need balancing / aligned
Auto box mounts bit flogged out
Engine mounts
Front bushes getting old
How good is your auto fluid ?
Around 70 the Auto will kick in and out of O/D , think the TCC under light acceleration is around 55
Try it with the power button on to eliminate the overdrive cutting in

Mine VX11 drops in and out cruising around 70 and gives me the shits . I push the power button on to stop it