Clunk, changing gear, accelerating, lifting off

Hi, not long had my disco and come across a problem. When I change gear up or down and relase the clutch theres a bang from somewhere in the transmission and can't determine where. This also happens when you lift of the accelerator and go top it your foot down.

Checked the props seem ok, took the plate of the back of the transfer box to get the gear out but can't figure out how to take it out? How do I take it out or any other suggestions on what it could be? Thanks

Had a similar noise on mine. It was some loose bolts holding the handbrake drum.

Maybe A frame ball joint?

beerdude said:

maybe a frame ball joint?

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+1

Could be lots. Drive flanges easy to check, prop uj, loose prop bolts, a fram bj as mentioned, trans case input gear as you mention or central/axle diffs, driveshafts etc...
I asked the question on the input gear removal on a disco lt230 and have been told it is not possible. Ashcrofts say it is if you spin the rear output flange until gear teeth line up then you can pull it out? Dunno. You can check for wear in situ anyway just rock car with pto cover off.

So I take the cover off and rock back and forth what should I expect to see? Checked the a frame ballpoint, no movement up or down

You need a lever in between the diff housing and the "A" frame to check the balljoint properly. the Transfer case input gear should be removable once you remove the bearing support, (round), plate from the rear of the transfer, check for spline backlash by using a torch and mirror up behind the case and have one rear wheel slightly off the ground, engage first gear and get someone to rock the elevated wheel back and forth, you should be able to see if the gearbox output spline to input gear is worn, (a common problem in earlier Disco's, some in fact wore the spline right out of the gear), the later versions had a full length spline engagement and lubrication inlet holes to aleviate the problem.

This is with the cover off looking in

tommyt01 said:

This is with the cover off looking in

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Red ****e signifies wear as it is swarf from splines wearing. Post that vid on youtube and then link on here so people can see if it looks like there's too much slop. Dont panic as it doesnt mean your disco is knackered, it will soldier on! Is it an lt77 200tdi or r380 300tdi? Later ones had cross drilled gear for lubing this up but low oil can wreck it in either!

https://m.youtube.com/watch?v=2BjUrypbrWk

Hope the link works? Not the best but hope you get the jist

It's a 300tdi 1995 m reg

Im no expert but looks like gear and shaft have some play. James Martin will confirm!
If the shaft is worn its a replacement box to sort. Input gear can be replaced but in situ on a disco lt230 is open to debate, some say yes some say no! They are about £70 new.
Or as I mentioned welding will fix! Forever!
Some have hammered thin nails into the worn splines. Its like a thin tack type nail. Thats a mega bodge but will take up the slack. You could put some jb weld in then to seal.
If both are worn a replacement gbox and trans case would not be a lot 2nd hand.
Or just live with it and be careful on changing gear.
Good luck others will have more info

You say a full replacment box, can't I just strip the box down and replace the mainshaft and the input gear?

tommyt01 said:

You say a full replacment box, can't I just strip the box down and replace the mainshaft and the input gear?

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You can do, I wouldnt fancy doing an r380 mind, its not generally a diy job. Before you get ideas id wait for someone with more experience than me comment on your video.

tommyt01 said:

You say a full replacment box, can't I just strip the box down and replace the mainshaft and the input gear?

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input gear is easy enough to change youd want ftc5087 if its std 300 tdi disco box ,but mainshaft is a full box strip and rebuild which requires pullers and a press etc

Not bad backlash as I would have expected, from your video, maybe that spline is ok. Check all over the drivetrain, e.g front axle/hub drive adaptors, cv joints, centre diff output shaft bearings, diff backlash.

check the rubber doughnut at the end of the shaft connecting to rear diff

theres more than enough wear on those splines to cause a very noticeable clunk

How do I change the input gear or even check the mainshaft splines for wear? I've took the cover off but can't see a way of getting the input gear out? Do I have to drop the gearbox out just to look?

youd need to pull t/box off if its 1.222 std disco box