Gear box/Transfer shifting
Submitted: Tuesday, Nov 28, 2006 at 21:12
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Member - Nick (Kununurra)
Years ago when I was selling a 4wd, the dealer where I was selling it slipped the transfer into neatrul and ran the gearbox through its gears.He stated that he was looking for stuffed bearings in the g/box.First was quiet and each gear got noisier until fifth was quite noisy.He then said, gear box is stuffed that'll be two grand less mate.
Dunno why but been thinking about it lately.What do you guys reacon?Wouldnt the box be noisier due to no load being placed on the gears?The faster they are spining, the noisier they'd be unloaded??
Cheers Guys
Reply By: Member - Axle - Tuesday, Nov 28, 2006 at 21:34
Tuesday, Nov 28, 2006 at 21:34
And if you did that to the one he was trying to sell you, his answer would be???.
Cheers Axle.
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Follow Up By: johnny - Tuesday, Nov 28, 2006 at 21:51
Tuesday, Nov 28, 2006 at 21:51
good point
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Reply By: cowpat - Tuesday, Nov 28, 2006 at 22:13
Tuesday, Nov 28, 2006 at 22:13
The gears always turn at the same speed but the output shaft turns faster. Yes it is noisier in the higher gears, but how noisy is ok is relative and I think would need an ear more experienced than that of a car dealer to judge if it was normal or the output bearing was going. Mostly the input bearing goes first anyway and would make much the same noise regardless of gear.
If you remove the rubber boot around your gearstick so you can see the ground and then go for a drive - now that's noisy! Sorry Nick but my little experience with these things suggests you should try to do the same next time you buy another to get that two grand back. Funny story anyhow, thanks. Casper
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Follow Up By: Member - Nick (Kununurra) - Tuesday, Nov 28, 2006 at 23:24
Tuesday, Nov 28, 2006 at 23:24
That was near twenty years ago but it was selling my first suzuki.When we got the one yesterday it reminded me and running it through the gears it is the same.So either both were/are stuffed or both fine.No strange noises at all from transmission while driving.
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Reply By: fisho64 - Tuesday, Nov 28, 2006 at 22:16
Tuesday, Nov 28, 2006 at 22:16
so did you sell it to him for 2 grand less?
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Follow Up By: Member - Nick (Kununurra) - Tuesday, Nov 28, 2006 at 22:19
Tuesday, Nov 28, 2006 at 22:19
Yep, sure did.At 17 the car dealer new best.Now if it was to happen now it would be a bit differant.
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Follow Up By: fisho64 - Wednesday, Nov 29, 2006 at 00:01
Wednesday, Nov 29, 2006 at 00:01
thats sad, but a learning curve also I guess.
sort of similar to the old saying that goes
"if you lend a bloke $20, and never see him again, then its probably the best $20 you will ever spend!"
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Reply By: Bilbo - Wednesday, Nov 29, 2006 at 00:03
Wednesday, Nov 29, 2006 at 00:03
Nick,
I'd say he was having a $2000.00 lend of ya. That's no way to test a gearbox. It proves nothing. Best to test a box under load. Test the how sound the synchros are by changing down at a relatively high road speed and see if it it flies out of gear. Do this in each gear. If it "thumps' out of gear, then the synchros are failing or the selector
fork detent springs are broken. The latter is least indicative and least likely.
Start the engine with the clutch engaged, foot OFF the pedal, and listen for a 'whirring" noise. If there is a noise, the primary shaft bearings are on its way out. The push the clutch pedal down (engine still running), if the noise disappears then the primary shaft bearing is DEFINITELY on its way out. If another, different noise appears at this point then the clutch thrust bearing is on it's way out.
Put in reverse and listen for a "growling" noise. If it's there, then the layshaft or reverse shaft bearings are rooted. This test is best done by reversing up a slight slope. This puts a lot of load on the bearings.
If the gearchange is "crunchy" then it could be synchros or mainshaft bearings. Either is a total box strip down.
If there's a "moaning' noise in 5th then the rear main shaft bearing is likely going to fail. If it whines or moans in all gears and the noise is coming from the back of the car (rear wheel drive), the diff's knackered.
If the gearchange is "snicky" then it could be poorly aligned selector forks or sticky selector forks (or bad clutch adjustment).
Here endeth the first lesson.
Take care,
Bilbo
AnswerID:
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Follow Up By: Willem - Wednesday, Nov 29, 2006 at 10:16
Wednesday, Nov 29, 2006 at 10:16
Hi Bilbo
Your 'lesson' had me intrigued, so I just had to test it.
My truck was bought 2nd hand and previous owners burnt the clutch and warped the flywheel. Much stuffing around here in the sticks with local mechanic(box came out 3 times) to repair rear engine seal leak. Replaced clutch, flywheel, thrust bearing and spigot.
The 'old' thrust bearing was making a noise but when taken out looked fine.
Anyway there is a faint noise again and with the clutch depressed the noise goes way. Probably still good for another 100,000 clicks :-) 1st, 2nd,3rd, 5th and reverse gears are quiet but 4th is a tad noisier.The gearbox is scratchy at times through 3rd and I assume the synchros are failing but the box should still give a fair amount of service before a rebuild is needed. Truck has 328 on clock
Cheers
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Follow Up By: Bilbo - Wednesday, Nov 29, 2006 at 22:31
Wednesday, Nov 29, 2006 at 22:31
Willem,
Sounds like the primary shaft (AKA spigot) shaft bearing is noisy. But if it's a GQ box ut'll be good for another million kms!
As for the "scratchy" 3rd gear, you'll find with most, if not all gearboxes that any weaknesses in synchro function will show up initially in the third and second gears. This is because these are the gears that get most hammer when changing down for corners. They are subject to bigger rotational speeds versus each other (i.e a bigger difference in rotating speeds) within the gearbox when the synchros are doing thier job. At the same time as all that, they are also subject to the engine being in a high RPM/high torque range when being asked to change gear!
They are also the gears furthest from any support from the bearings at each end of the box.
That's a lot to ask for a little old synchro ring and cone! So they wear out first - usually.
Take care,
Bilbo
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