Clunking noise when lifting off the trottle

[Merlot man]

Good evening everyone ,
I'm back with yet another question and hoping for some more great advice
In the last few days I've noticed that when driving the bus at between 55-60 mph if I lift of the trottle I get a disturbing "clunking" noise coming from the rear passenger side , it clunks in a rotating fashion until I slow down or re apply the loud peddle .
Thoughts are that it might be the transfer box or rear prop shaft but don't know really . I've been under the bus and there's nothing obvious to see .
I'll try and get a mechanic to look at in the next week but I'm hoping that it's a known fault , you know the ones that are easy and cheap to fix ( that would make a first for me )
Thanks you in advance , your help is be greatly appreciated !
Brian

[Northern Bongolow]

props are known to go at the universal joints, is yours 4 wheel drive or 2. get underneath and grab the prop and try to rotate it backward and forward, if its the prop the slack in the joint will show up sometimes the splines can be worn too.

other things to check might be exhaust / bracket/hanger/rubber gone. suspension spring broken. rear drop link snapped, anti roll bushes baggy letting anti roll bar move up and down when power on /off. suspension bush worn.

my money would be on the anti roll bar bushes or drop link, standard stuff on on a 2 ton bongo.

ps, whats a trottle

[Merlot man]

Good morning northern bongolow and thanks for the reply .
I have a 95 2.5TD 4 wheel drive .
Ive just replased the rear anti roll bar D bushes and their brackets , the drop links to be fair look in good condition but ill have another proper look tomorrow . The rest of the bushes while old seen to be in acceptable condition but again ill give them another examination.
I'm expecting an air lift kit to be delivered next week so that can only help.
The exhaust is solid as by shaking it there is no movement .
I think you could be on to something with the rear prop shaft as the clunking is like its "rotating" so going to look at that tomorrow , are you saying to rotate it left and right and try to see /hear movement ? also forward and back to check the sliding joint ?
I'm kinfd of hoping its this as its looks easy enough to replace and get reconditioned (lasy bXXXXXd )
Thanks again and keep them coming
Brian

[Merlot man]

ps, whats a trottle
Sorry about the spelling , not my strong point

[Bob]

If I got pulled up for every typo I wouldn't post much.

[Merlot man]

If I got pulled up for every typo I wouldn't post much.

Thanks Bob ,I've just read my morning's post and found a number of "special " spellings (don't tell them your a teacher )
Brian

[Bob]

ps, whats a trottle
Sorry about the spelling , not my strong point

Trottle:

Slightly faster than walking but not a full jog.

[alant54]

ps, whats a trottle
Sorry about the spelling , not my strong point

Trottle:

Slightly faster than walking but not a full jog.

Trottle.....sounds like a good fuel economy tip... ...especially for a Bongo...

I just love the banter on here and I never make speeling mistakes...well not often anyway....

Coat is worn out ...must get a new one....

Alan

[Merlot man]

Good evening all and thanks for the replies
I've looked at all the points you suggested northern bonglow but could find nothing obvious
A friend and I spent all day under the bus cleaning off old under seal in preparation for a new coat tomorrow Very dirty but really satisfying !


Can anyone tell me what the rubber block is on the rear axle is , at the end of the prop shaft ?
Thank you all for your help , I I'm finding this a great site !
Brian

[Bongolia]

Not noticed anything on mine and not sure what I am looking for in the image but sometime things like this are vibration dampers, Could that be it?

[rita]

If you mean the rubber block bolted to the diff (to the left of the r/h axle stand) its called a Harmonic Damper, these are used to eat the vibrations caused by the final drive.

Good Luck.

[Merlot man]

Good evening everyone and thank you Rita for the reply .
I looked under the bus today again and there are two " harmonic balancers " one on the rear of the gearbox and on the front of the rear axle . Both are really a block of rubber bonded to a heavy gauge steel frame and I assume are designed to move with the vibrations of the transmition system to balance vibrations out and ,on mine at least, both rubber bits move but on the gearbox one the rubber seems very easy to hit off the steel frame where as the axle one will move but not hit the steel frame .
Does this sound normal of could this be my problem ?
Thanks in advance
Brian

[Bongolia]

Can you post images of the two you refer to, if they are dampers then its not likely that they are the source of your problem ,if the noise is rhythmically related to road speed then it is more likely along the lines of NB`s post and UJ related, they can have tight spots too.

[Merlot man]

Good morning everyone
This is the gearbox rubber block that I was talking about

[Merlot man]

And this is the one from the rear axle



Both move but the gearbox one is easier to move than the axle one , does this make any sense to anybody
I still plan to have a proper look at the prop shaft , maybe by a local mechanic
Thanks for looking and helping me out
Brian