Monday, Jan 04, 2010 at 13:37
I agree with Stan, but admit to having had some misgivings in the past.
I have a 2000 Patrol (ex- 4.2TD) that had a heart transplant from brand new (naturally aspirated 6.5 Chev V8 diesel with more torque than the 4.2TD).
Despite the truck having now done 240,000klm and most of that has been towing something (or so I believe..... I have only owned it for the past 60,000klm), it's still going strong. I tow our Ultimate in 5th gear most of the time, but not into a headwind or up moderate to steep hills etc.
One arguement which has some validity for towing in 4th relates to EGTs (exhaust gas temperatures). With the turbo engined rigs, it is important to ensure the EGTs stay within specifications.
When I owned my previous vehicle (also a 2000 GU Patrol with 4.2TD, but not the same rig I now own), I had EGT gauge with sensors both above and below the turbo. I was REALLY surprised by how much the temps would DROP when I changed back from 5th to 4th gear under load. It seemed to defy logic....... you're pressing along up a moderate
hill in 5th gear, revs and speed are starting to drop and EGT is going up and up. You drop her back to 4th, revs build up, speed starts to hold steady or even increase AND the EGTs would start to drop. This alone is a good enough reason to use 4th gear when towing in "adverse" conditions.
As for the gear box strength, they aren't designed to be heavily loaded in 5th gear as it is a small cog that sits off to the side of the main shaft. But, under moderate and constant loading, it should be quite okay.
The Patrol gear boxes circa 2000/1 did have a defective main shaft, which hadn't been machined for the correct spline length. This resulted in many gearboxes carking 5th gear, but it was rectified by 2002.
Cheers and I'll look forward to seeing you on the Ultimate
forum in due course.... We've owned our Ultimate (number 56) since February 1999.... I'm sure you'll be pleased with your decision.
Roachie
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