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R72 Gearbox Output Shaft Bearing Removal

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05 Apr 2018 18:53 - 05 Apr 2018 18:54 #191346 by Max Headroom
Cheers Riccy!

the clutch bite is about where I would expect a well-adjusted clutch to bite (My neighbours Jimny is terrible; the bite is right at the top making me think her Jimny may be due a clutch change soon)

I have a new block-paved drive and I'm very aware of leaks from cars - not a drop from this beast, and having got under the car (without jacking it up) there is no sign of any oil leakage anywhere - it looks really very good.

I will look for Redline MTL oil for the next g'box drain/fill which leads on to another question - how frequently should I do this given the notoriety of the R72 g'box?

Again my sincere thanks Riccy - all good gen :)


IF IT AINT BROKE, KEEP FIXING IT UNTIL IT IS
Last edit: 05 Apr 2018 18:54 by Max Headroom.

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06 Apr 2018 11:01 - 06 Apr 2018 11:05 #191373 by yakuza

Busta wrote: I believe the issue is entirely due to lubrication, hence the replacement bearings often being a sealed type. I'd be very surprised if it was related to the load on the bearings. Many people are running bigger engines with these gearboxes and we see no evidence of this accelerating the wear or causing premature failure.
Also the problem does not seem to be present in the more recent Jimnys (I believe Suzuki fixed the problem around 2008/9?), even though they are still using the same gearbox.

Lubrication is the only reason for choosing sealed bearings i guess. It is hard to tell how the oil behaves inside a running gearbox.

The 20% difference in the gearing for Mark III VVT models relates to approx. 20% more load/ torque in the R72 gearbox compared to the 98-04 models. And the same for the Transfer box as the later VVT models transfers 30% less torque in the high range.
Also the VVT has a slight increase in torque from the engine.
Not saying this is the most important or biggest reason, but it is a major change between these models.
20% more load may not decrease the bearing life time either necessarily. Very often a no load situation is the worst for the bearing lifetime.
It could just as well be the rpm the non loaded bearings spins at, or the way the oil splash around in there.

I have not done any calculations here, just using common sense and experience from my work designing gearboxes for ships.
Our gearboxes usually have around 1000rpm in and 200rpm out and from 500 to 20000kW:
scanapropulsion.com/products/reduction-gearboxes/

Norway 2005 Jimny M16A VVT, 235 BFG MT, 2" Trailmaster, ARB rear lck, 17%/87% high/low gears.
Last edit: 06 Apr 2018 11:05 by yakuza.

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  • OlaGB
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06 Apr 2018 13:02 #191374 by OlaGB
Replied by OlaGB on topic R72 Gearbox Output Shaft Bearing Removal

yakuza wrote:

Busta wrote: I believe the issue is entirely due to lubrication, hence the replacement bearings often being a sealed type. I'd be very surprised if it was related to the load on the bearings. Many people are running bigger engines with these gearboxes and we see no evidence of this accelerating the wear or causing premature failure.
Also the problem does not seem to be present in the more recent Jimnys (I believe Suzuki fixed the problem around 2008/9?), even though they are still using the same gearbox.

Lubrication is the only reason for choosing sealed bearings i guess. It is hard to tell how the oil behaves inside a running gearbox.

The 20% difference in the gearing for Mark III VVT models relates to approx. 20% more load/ torque in the R72 gearbox compared to the 98-04 models. And the same for the Transfer box as the later VVT models transfers 30% less torque in the high range.
Also the VVT has a slight increase in torque from the engine.
Not saying this is the most important or biggest reason, but it is a major change between these models.
20% more load may not decrease the bearing life time either necessarily. Very often a no load situation is the worst for the bearing lifetime.
It could just as well be the rpm the non loaded bearings spins at, or the way the oil splash around in there.

I have not done any calculations here, just using common sense and experience from my work designing gearboxes for ships.
Our gearboxes usually have around 1000rpm in and 200rpm out and from 500 to 20000kW:
scanapropulsion.com/products/reduction-gearboxes/


Good point regarding increased load, but maybe hard to compare head to head as the gearboxes are different built.
And the amount of load is pretty low? Very little power, and low viechle weight.. And the problem seems to be mainly on 2005-2007 models?
But it`s a VERY little and light weight gearbox, so im almost suprised it holds up as good as it does :D

Both bearings that i found to be noisy just by spinning them in my fingers, where from the countershaft. Which sits the lowest of all shafts in the box, submerged in oil.
The bearing that`s been the worst for several people, is the rear counter shaft bearing. This makes me think contamination issues due to where it sits? Can also be the one with highest load, its way above my gearbox physics knowledge ;)

I`ve done some googling on the seal vs no seal bearings in transmissions, but found very little information. Some claim its very common in modern gearboxes, others are sceptical.. Cant find much reliable info about it..
The company that sold me the kit (which by the looks of it, only sells bearing kits to different , told me they had done theire research and ensured me the sealed bearings was a upgrade. And claimed that the choice of open bearings where due to cost. Trustable info? No idea.

Would be interesting to open a 2014+ box, and see what Suzuki`s opinion is.

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