Series 3 Drivetrain/Gearbox woes

Hi all,
Yet another issue has arisen, On my way home from shelsey walsh the other week i started getting a really loud knocking noise as I'd come to a complete stop, the last few meters rolling whether i'd be in gear, out of gear, clutch in or out, hi - low or even neutral (although neutral does seem tricky to find in terms of Hi and Lo range), but its more than noise you can feel it jolting the truck around, theres now also the sound of a scraping brake drum too.

Do not want to drive this around anymore till i can sort whatever it is out before it causes further damage.

But it only makes these noises as im coming to a stop, no noises as im driving around, tried checking the front axle as at first I thought it may have been the free wheeling hub/s not fully engaged as the sound appears/feels front end/right under my bum. But with 1 wheel in the air i tested both sides out and all seems well.


Any ideas for me to check as im at a loss and dont have lots of free time to pull everything apart to inspect piece by piece, keeping fingers crossed its not the transfer box

thankyou in advance

Is the noise just when you press the brake to finally stop , and using gears to slow down is ok and braking at 20mph ok

both of those scenarios are fine no noise from either

I would check the propshafts first for loose bolts , ujs ok ,
If it brake related you could clamp flexis to isolate brakes to either front or back which Might help pinpoint the problem area, have you checked for play in wheel when jacked up

Jack each corner up and check for play in your wheel bearings / king pins.
Also check all wheel nuts tight.
Also check propshaft UJ's

Sounds like the handbrake could be sticking - this results in a clunking when moving at slow speeds and hightlights all the back lash in the drive train. It always feels like a big gearbox / transmission issue when its the hand brake catching - clunking and knocking.

Yes check if the hand brake drum is hot. If they bind a bit they get very hot and sieze up. Plays hell with the transmission and gear changes. You'd think the heat would expand the drum but it seems to expand the shoes more.

If it only happens when braking I would remove the brake drums to inspect, starting with the hand brake as mentioned above. If one of the pistons is beginning to seize or one of the retaining springs has broken causing it to catch the drum you can get some very serious sounding noises.

braking doesnt affect the noise/jerking for better or worse, im liking the handbrake idea, will give that a look at over the weekend

Unlikely to be the drive train with those noises. I agree as posted it’s more likely a brake problem. Have you inspected the axle? It could be related to a collapsed or failing backing plate which holds the brakes against the axle.

Had a quick look at the props yesterday. Front seems healthy. Rear u joint by the handbrake has a small amount of play and there's a small amount of play between the two halves of the propshaft.

Also is it normal to almost be able to do a quarter turn with the prop either front or rear before they engage against something?

Next weekend when I have more time I will inspect wheel by wheel

Stormintrooper said:

Had a quick look at the props yesterday. Front seems healthy. Rear u joint by the handbrake has a small amount of play and there's a small amount of play between the two halves of the propshaft.

Also is it normal to almost be able to do a quarter turn with the prop either front or rear before they engage against something?

Next weekend when I have more time I will inspect wheel by wheel

Click to expand...

Not really, there's a lot of backlash through the transmission but there should be no play at all within the the U/Js or prop slider.

I think its always been like that, being able to rotate front or rear prop an almost quarter rotation before either axle starts turning the wheels.

I remember noticing that after putting in the rebuilt gearbox because i had almost no issues lining up the output of the transmission to the props as I could easily turn them either way to align it back up

Front output section of gearbox has a dog clutch so lots of slack before it will drive wheels.
Rear does not so lot less , if drive flanges splines on hub are worn they give extra slack as do ends of halfshafts worn also worn diff.
Easy to check halfshafts and drive flanges , just need some split pins felt seals and gaskets.

Potentially daft question I know

But in an effort to narrow down where the fault is, would it be safe to drive if i removed front and rear prop shafts one at a time? as in with the rear off select 4 wheel drive and have the front axle do the pulling? Or would I be wasting my time? more so because whilst im aware I have play in both the rear U joint and rear prop halves, I'd like to be able to confirm its those at fault as im not 100% sure and dont want to spend money on them just yet if they're not whats knocking the car around.

You can drive on the front only with care [ sometimes the steering will pull to one side because of the diff doing its thing, just something to be aware of not a big problem. Any FWH have to be engaged of course.