Transmission noise.

[yogi]

Over the last 2000 miles my 1991 manual has developed a rattle which gets a bit worse when its warm.

ONLY makes noise when the clutch pedal as released, when the pedal is pushed in (disengaged) the noise disappears entirely.

Its got quite loud lately, and today I decided to investigate. The noise seems to be coming from the bellhousing, or at the furthest from the front of the gearbox, I'd be certain its not coming from the transfer box.

When I changed the gearbox and transfer box oils it made no difference at all, although I did noitice a little bitof swarf on the drain plug magnet on the transfer box.But it really was only a little bit,like a fine dusting. BUT this noise does seem to be only coming from the front of the gearbox/clutch region when I'm underneath the truck.

Now I would just say clutch release bearing/input/layshaft bearings and investigate further BUT.....
when I stick the transfer into L the noise gets worse, not a massive amount louder, but definitely a bit louder (say 10-15% louder).

Why is that happening?

Also, when driving I can feel (but not hear) a slight vibration if I put my hand on the transfer lever; I know I need to replace at least one U/J, I just haven't done it yet, but now this is all making me think a bit??????

Any ideas................

 

[joinerman]

Sounds like a failed thrust bearing in the clutch to me yogi

 

[yogi]

Sounds like a failed thrust bearing in the clutch to me yogi

Me too,but why does putting it into low range change the noise??

 

[frank rabbets]

Yogi do you mean putting it in low range but with the main gearbox in neutral with your foot off the clutch pedal ?

If so I would say it is the different position of the low range mechanism causing the noise to change. The most likely suspect is the clutch release bearing . But yes it's annoying when you are not sure.

 

[yogi]

Yogi do you mean putting it in low range but with the main gearbox in neutral with your foot off the clutch pedal ?

If so I would say it is the different position of the low range mechanism causing the noise to change. The most likely suspect is the clutch release bearing . But yes it's annoying when you are not sure.

Yes Frank thats exactly it!

I'm hoping your right. Should get time to get a better look/listen today over a friends pit, so I'll report back if I can determine anything else. I'm hoping thats all it is!!

 

[frank rabbets]

If the problem is in the gearbox it will be a low/muffled knocking sound or slow rumbling sound relating to the spinning of the input shaft and lay shaft. Nothing is turning in the transfer box. If it is a crisp rattling sound it's more likely to be the clutch release bearing or fork ends. Most often, however, when the bearing fails it makes a whirring noise with the pedal depressed caused by the square dried out balls spin round . Hopefully it's round dried up balls rattling but then going silent when you depress the pedal. Hope you get convinced this p.m. one way or the other.

 

[clivehorridge]

I have a similar symptom.

With engine ticking over and the clutch depressed, I only hear the sound of the engine ticking over. When I release the clutch I hear soft rasping noise that sounds like a dry bearing running.

I imagine it to be a dry thrust bearing, but I can't be sure without stripping it down.

It was like this when I bought the truck 8 years and 140k kms ago, and it's got no worse or better since.

I call it character.

 

[yogi]

Well hopefully I'll have something to report tomorrow because I only in the door, today was a little more hectic than I like!