Hi all,
I am pretty new to this mechanical game.
I have a question I hope someone can help me with.

My little 1200 ute makes banging sort of sound when I take my foot off the accelerator when I am going along in 3rd or 4th gears. I cant really pick where the noise comes from.
It sounds too far back to be the gearbox, but I dont know how to determine what is causing it.
I suspect the gearbox (5 speed on an A15 motor), but I would like to know the best way to check if it is or not.

Thanks

it is very hard to check but if it is only making the noise when going from 3rd to 4th i would suspect the gearbox but it is very har to tell as noise travles in the car.

I am surely finding it difficult to locate.

It doesnt happen when I am going 3rd to 4th though.
It makes it when I am in either of these gears and I take my foot off the go pedal.

so are you saying that it makes the knock knock sound when in any gear does it happen when the foot comes of the gas. you havent notced that it doesnt start cold or anythin unusal maby a slight miss under load this is a tricky one

It only seems to make the noise in 3rd or forth gear when I take my foot off the accelerator.
It is sort of a banging noise.
It starts fine in the cold. Takes a little while to get to idle though but I put this down to the Weber on it.
It doesnt miss or fart under load or anything like that.

i am quite stuck it could be a number of things to much fuel= backfire screwed gearbox i mean lets face it datsun boxses have never had a good 3rd gear
last but not leased it might be an engine fault
sorry i have run out of ideas

Its not a backfire type noise.
The engine runs and sounds fine.

Thanks for your thoughts anyway

Hi Ernal,

Sounds like you have may have something wrong with the rear. Check for a broken shock, excessive play in the universals, excessive backlash in diff or loose/broken spring mounts. Doesn't sound too major. Let us know if you need any help.

Hi Teretonga

The noise sounds to be coming from further back than the gearbox, so hopefully you are on he right track.
How do I check play in the uni joints and backlash in the diff?

lift the rear of the car, and put jackstands under the rear axle. then with the trans in 4th gear, slide a prybar through the yoke at the rear of the driveline, (make sure that the prybar is on the differentual side of the rear ujoint), then try to rotate the driveline back and forth.
this will do 2 things at the same time, 1 it will check for slop in the trans, if it's there, you'll hear it. 2 it will allow you to check for slop in the ujoints. if its there, you should be able to see it.
to check backlash in the diff.,set the emergency brake and put the trans into neutral, there should be a small amount of back and forth play, anything more than just a wiggle is too much.
if that does not make your problem show, it could be the spider gears in the diff., to check them put the trans into gear, have one wheel off the ground , the other on the ground and try to rotate the wheel back and forth. that will check for play there. there should be no give at all.
good luck