how weak is my 5th gear in my GU 2005

[discothrasher]

Is my 5th gear in my 4.2 st-s GUIV 2005 Very weak, as I have been told dont go with the 81% gear reduction as your 5th gear is weak and will break if i drive in 5TH low range especially towing the camper
Any info will help thanks
Kelvin

[WICKED]

Why would you be towing in 5th low?

I don't own one, but my neigbour was towing a single axle jayco in 5th on a flat road and blew it.
Apparently in the GQs there is a circlip that stops the gear moving on the shaft but in the GUs there is no circlip and blowing them is common.

[GeneralFubashi]

Wasn't that fixed for the 2002 model on? I've still never heard of anyone towing in 5th low though. Thats a recipe for problems.

[raptorthumper]

There is no problem with 5th gear failures after late 2002. The issue was a loose spline from manufacturing and incorrect dimensions/toleraances. Nissan acknowledged the problem and released a new shaft and gear which has an additional boss and requires a heavy press fit on the spline. I have never heard of anyone "breaking" 5th gear, only worn out splines from vibration. Most failures were diesels as the torsional vibrations are worse on a diesel. I put the full power of an XR6 Turbo engine, in 5th, all the time, through my GU gearbox.

**EDITED** Added this here on my earlier GU 5 speed rebuild.
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I thought i would post pics of the new parts available for GU 5 speed boxes, that are much stronger. I believe both series 1 and 2 GU's are affected. No more failed 5th gears.

Parts are available from nissan for $513 approx but you can get a better price if you have a good relationship with dealer. Nissan acknowledge the problem.


If i had an early GU 5 speed i would replace with new parts during a clutch change for peace of mind.
































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[discothrasher]

Why would you be towing in 5th low?

I don't own one, but my neigbour was towing a single axle jayco in 5th on a flat road and blew it.
Apparently in the GQs there is a circlip that stops the gear moving on the shaft but in the GUs there is no circlip and blowing them is common.

Have taken my camper on some extremr tracks very really get to fith but do somethimes cape york / kimberlys/ect ect

[discothrasher]

Thanks for the positive informative post

There is no problem with 5th gear failures after late 2002. The issue was a loose spline from manufacturing and incorrect dimensions/toleraances. Nissan acknowledged the problem and released a new shaft and gear which has an additional boss and requires a heavy press fit on the spline. I have never heard of anyone "breaking" 5th gear, only worn out splines from vibration. Most failures were diesels as the torsional vibrations are worse on a diesel. I put full power of an XR6 Turbo in 5th all the time.

**EDITED** Added this here on my earlier GU 5 speed rebuild.
*******************************************************************************


I thought i would post pics of the new parts available for GU 5 speed boxes, that are much stronger. I believe both series 1 and 2 GU's are affected. No more failed 5th gears.

Parts are available from nissan for $513 approx but you can get a better price if you have a good relationship with dealer. Nissan acknowledge the problem.


If i had an early GU 5 speed i would replace with new parts during a clutch change for peace of mind.
































-

[discothrasher]

Wasn't that fixed for the 2002 model on? I've still never heard of anyone towing in 5th low though. Thats a recipe for problems.

Well there always a first, and now you have, been new to nissan I am learning, my D2 used to tow just fine in low 5, can you tell me why its a recipe for problems

[raptorthumper]

Updated GU gearbox parts are now selling on ebay.


http://www.ebay.com.au/itm/Nissan-Patro ... 51a35c15f2" onclick="window.open(this.href);return false;


_

[danaz]

By fitting the reduction gears you are actually reducing the load on the gearbox, only the Diffs and axles will see a higher torque. Unless you mean you'll be in 5th more often? I often tow in 5th low just to cruise at a reasonable speed between harder sections to save constantly stoping to go from high to low and vice versa, I don't think you would be doing this with reduction gears however as it'd just be too slow. Even if your planning to use 5th low on hard sections of track I can't see the load on 5th gear being anywhere near as high as on the highway due to the torque reduction unless there's massive shock loads from bouncing up rocky tracks etc.

[discothrasher]

By fitting the reduction gears you are actually reducing the load on the gearbox, only the Diffs and axles will see a higher torque. Unless you mean you'll be in 5th more often? I often tow in 5th low just to cruise at a reasonable speed between harder sections to save constantly stoping to go from high to low and vice versa, I don't think you would be doing this with reduction gears however as it'd just be too slow. Even if your planning to use 5th low on hard sections of track I can't see the load on 5th gear being anywhere near as high as on the highway due to the torque reduction unless there's massive shock loads from bouncing up rocky tracks etc.

Danaz thats what i was thinking, thanks for your answer, with what you saying about towing in 5th its exactly what I do,
I have gone with the 43% reduction,