Knocking sound when speening up.

[Antipf_bfs]

Good day guys.
Me and my G/F went yesterday to Beartooth pass MT/WY. almost 11000ft at the top. When we get there I drive throe the snow to get to the parking. When I start my car and start moving I notice knocking sound. First I was thinking it was because engine was running rich. But when we get down to the wally sound dint stop. Speed and volume of knocking increase as you accelerate. In cruse knocking ceased. When in park there is no knocking.

Disco 2 1999 133K miles.

Sorry for butchering English ;-)

 

[Maddie]

Are you sure it isn't ice build up on the universal joints like once happened to me? I got under my truck and noticed that the shafts and joint had about three inches of ice stuck to them and were hammering the dog house.

 

[Antipf_bfs]

I don't think so. Temp was +7c outside. I did get under the car at the bottom of pass and didn't notice anything unusual.

 

[Maddie]

Is it still knocking down in lower warmer weather?

 

[Maddie]

So at 40f approx 7celsius it is still knocking?

 

[Antipf_bfs]

Yup. after few days still doing same sound. If I hit throttle in neutral or park there is no knocking.

 

[joey]

If I were to guess I would say you have a U-joint about to come apart

 

[Maddie]

Joey: don't you think it would only knock whilst letting of the gas and then reaccelaratting unless it's really worn and vibrating the vehicle? Maybe a rod knocking?

 

[joey]

Not always... but in most cases you would be correct. I would look since the D2 u-joints are not grease-able.

 

[Disco Mike]

Have you ever had the front drive shaft rebuilt, installing 2 new greasable u-joints and a centering ball kit? If not sure then crawl under your truck with a flash light and see how many grease fitting you can find on the front shaft, should be 3 plus a plug. If you don't find 3, then I would suggest you remove the front drive shaft, engage the CDL with a 10 mm wrench and drive on the rear shaft only to see if the noise goes away. If it does, then it is the front shaft.