The Toyota Landcruiser Owners Club

[werminghausen]

I am new to the Forum.
I bought a 2001 Prado, 3.4l, 5 speed manual. I am in Muscat Oman, Middle East . Car  made a strange sound during test drive when I was shifting gears. A 'bang' when releasing the clutch. I agreed with the owner to have the clutch inspected and to be changed if needed. The shop did change the clutch (was worn) and I thought the car should be fine but I found an even bigger bang when I am shifting gears now. Going back to the shop they said that the new clutch is very aggressive and would make this 'bang', not untypical. I am now stuck with this bad noise (the entire dash is shaking) and I am still thinking that this is not correct.
What could be causing this noise and vibration when releasing the clutch pedal? Is this a transmission problem or a clutch problem?
Martin

[Google]

[BobMurphy]

There was a similar problem reported here recently, it turned out to be a worn Universal Joint in the rear prop shaft.

I would start by checking all the joints on both prop shafts, three are easily replaceable but the forward one on the rear is a double-UJ "Hookes Joint" (which gives true Constant Velocity) and this, I understand, is not easily replaceable (they also don't suffer the same levels of wear as the others).

If its not one of the UJs we are into deeper water.

Possible causes could be:

1. Broken or loose engine or gearbox mountings.

2. Worn differentials in the axles which have excessive rotational free-play.

3. Worn gear pinions / bearings in the gearbox producing excessive slack.

4. Wear/damage to the centre differential in the Transfer Box. If the car has been run on dry tarmac with the centre diff locked it can cause the differential's Planet Carrier to burst, producing clonks. I replaced this item for a member and it solved that particular problem.

Start with the simple things as they are the most likely to be the cause, the rest is just 'worst case' conjecture   .

Bob.

[werminghausen]

Hi Bob
Thanks so much for your help.
I am still  not familiar at all with the vehicle. I ordered a Hynes? manual to get some insight.
Prop shaft is the drive shaft? Are these the possible parts? I found on AutohausAZ
W0133-1805988   GMB  Universal Joint; w/ zerk fitting; Front  $47.62 SALE

W0133-1741937 GMB Universal Joint; Rear  $40.23  SALE

Would you just try and order the 3 parts ? and start changing or is there a method how to test UJs which ones are worn?
Where are the Ujs exactly located and are they easy to replace?

Martin

[BobMurphy]

Martin,

The Propellor (prop) Shafts connect the Transfer Box (behind the gearbox) to the front and rear axles. There is a Universal Joint (UJ) at each end of each shaft.

The UJs wear, meaning that there is slack in the four needle roller bearings within each UJ. To test them, hold the flange that connects the UJ to the axle differential and try to rotate the prop shaft. If you can see/feel rotational play in the UJ its time to replace it.

Here is a diagram of the front prop shaft to show what I mean:





I don't know what the part numbers you quote are, but "Drive Shaft" can mean the shafts that connect the axle differential to the wheel hubs ('Drive Shaft' on the front, 'Half Shaft' in the rear). Because the front differential is fixed and the front has independent suspension there is a joint at each end . . . A 'Tripod bearing' on the inner end and a Constant Velocity (CV) Joint' at the wheel end. We are not talking about those.

The Toyota Part Number for the front prop UJs is "04371G - 04371-35060 (SPIDER KIT, FRONT PROPELLER SHAFT UNIVERSAL JOINT)"

The kit for the rear prop shaft rear UJ is "04371H  - 04371-35060 (SPIDER KIT, REAR PROPELLER SHAFT UNIVERSAL JOINT)".

They are about £12.00 each here in UK (from Milners) and front & rear are the same. Here is a link: Milner's UJ.

As regards fitting a new one . . Here is a write-up I prepared earlier   :  Replacing a Propshaft UJ.

I wouldn't go ordering anything until you have checked for play in the UJs, just in case its something else.

Let us know how you get on.

Bob.

[werminghausen]

Bob,

thanks for your notes, very helpful. I understand now what the UJs are. R&RSeems to be straight forward.
You mentioned three of the four UJare easily replaceable but the forward one on the rear is a double-UJ "Hookes Joint" and tough but also not common failures.
I 'll check out if I can get access to these UJ. I just have a 1.5 ton car jack. Better to put the car on stands I guess.  

Again, I have an annoying bang when I shift gears and release the clutch. It is almost frighting as the entire dash vibrates. Mostly this happens in 1/2,  2/3 and 3/4 shifts, not when I start in first gear and not much in 4/5 shift.
I can try and release the clutch veeeeery slooowly and then the bang is  somehow less or missing. Bang is less when shifting with higher revs.

I hope that the u-joint are the reason. It can be they were never touched.
Martin

[benterrier]

Hi
I would get underneath your truck and check over the propshaft pretty quick. Sounds like one of the joints is about to fly apart. I had same dash vibrations in a Discovery.....soon after the propshaft fled off. Very dangerous and can do a lot of damage.

Regards
benterrier

[werminghausen]

Hi Benterrier,

will do.   Best, Martin

[werminghausen]

Prop shaft and U Joints:
I was under the car today and nothing seems to  be wrong with the U Joints. I found no play.
I was tuning the front and rear prop shafts to check play.  The longer rear  shaft has almost no play (I could turn it only slightly) while I could turn the front shaft (the shorter one) quite a bit.
Do you think this is within specs or could this cause the bang while shifting gears?

[werminghausen]

BoB
You were saying:   '2. Worn differentials in the axles which have excessive rotational free-play. ' as possible cause for the bangs.
How exactly would you define excessive free-play? I this the free play when rotating the prop shafts while truck is in gear and parking?

[BobMurphy]

[werminghausen]

Hi Bob,

I went under the truck again with gear in N and handbrake.
Didn't make a difference.
Front prop shaft has about 10mm of slack measured at the radius of the  13mm nuts/bolts (I guess less than 1/8 turn)
Rear prop shaft has about 2mm of slack, much tighter.

I'll try and disconnect the front one and see if there is a difference in banging.
Martin

[werminghausen]

I am trying to figure out what this banging is when shifting gears.
If I am very very careful and release the clutch slooowly, then most times the bang is gone.
Also I tried to coast in 3 and shift to four without using the clutch. It works just fine.
Next I tried:  drive, then decelerate, then step on the clutch pedal and release again, slight bang. I can repeat this easily. However if I drive, release gas only slightly, then step on the clutch and release again..it is banging harder.
Go and figure.
I honestly doubt it is the differentials front or back.
Can it be that it has to do with the clutch engagement?
Martin

[andy]

Have you greased the U/J's and also both sliding joints on the prop.
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[BobMurphy]

So, re-reading this post . . .

You tried the car and there was a 'bang' when changing gear.

The clutch was replaced and the 'bang' is worse.

I assume that the Mechanics who changed the clutch knew what they were doing and why they were doing it - did they really inspect everything around the flywheel and gearbox before installing the new clutch ?

Did they change the pressure plate and release bearing as well as the friction plate ?

Question: When driving normally, is there a noise when you take your foot off the gas and then power it up again (without touching the clutch pedal) ???

Possible causes of noise from the clutch action . . .

1.  Worn splines on the gearbox input shaft. One would hope that the garage would have spotted that. Also, it would produce a 'knock' when the clutch is fully engaged and the power is applied on-off - hence my question above.

2.  Something not right with the pressure plate, but its difficult to envisage what. The plate is spigotted to the flywheel and is held down by six bolts. Hopefully the pressure plate was replaced but the noise is still there, so not that then.

3.  Something not right with the friction plate. It has shock absorber springs built in which can wear/break. It should be new yet the noise persists so not that then. One should always trial-fit a new friction plate to the gearbox input shaft splines . .





I once spent two hours trying to re-fit a Landrover engine to the gearbox after changing the clutch (its easier than removing the gearbox) only to find that I'd been sent the wrong friction plate. Had it been a loose fit I wouldn't have spotted it until it was too late.

Unlikely to be the cause here as the plate is new (?) and I don't suppose the wrong parts were fitted twice (though I'm sure stranger things have happened).


4.  Loose flywheel   . I sincerely hope not. Its spigotted to the crank shaft and held on with eight megga-bolts. Most unlikely (and there would be other issues when driving).

5.  Something inside the gearbox. If there was lots of back-lash in the box it would show up when driving normally - hence my question above.

6.  Badly worn clutch release lever. The lever sits on a ball and socket joint with the release bearing on the inner end and the hydraulic slave cylinder on the outer end. If there was a serious problem with it the clutch action would feel very bad. I'm assuming the clutch pedal action feels normal ??

7.  Worn/badly fitted clutch release bearing. This sits over the sleeve that covers the gearbox input shaft, in front of the forked-end of the release lever. It is held onto the release lever with spring clips.

Not a good photo, but the best I've got at the moment:





If the release bearing had become separated from the release lever I suppose that there would be some noise. However, that would mean that the Mechanics didn't change the release bearing, or inspect the mechanism when the box was out. It all sounds very unlikely to me.


All of this is a long-winded way of saying that it could be a number of things all of which are unlikely because the clutch has been replaced. How confident are you about the Mechanics ??

Back to my question . . How does the car feel in use without the clutch release lever being pressed ???


I'll give it some more thought.

Bob.

[werminghausen]