100 series Landcruiser towing in 5th gear

From memory the non turbo 100 series had the same gearbox as the Hilux from the same year and the factory turbo 100 series had a stronger upgraded gear box.

With our previous Hilux D4D we towed in 5 gear a lot and sold it at 100000k with no problems.

There is merit as to why you shouldn't tow in 5 gear but how many gearboxes fail because of it is unknown and may be a bit of an urban myth.

Most have heard of it happening but not to themselves.

Iown a standard 4.2 diesel 2001 Troopy and have towed my camper 1200kg loaded for many thousands of kilometers over tha past 4 years in 5th gear with not a problem with the gear box.Surely if you are driving you will know when to drop dpown to 4th or stay in 5th as the response in the engine will tell you when to change gear. In my opinion and the opinion of some of my mechanic friends as regards a blanket "do not tow in fifth gear " is a load of rubish.

Nobby, yours would be a 105 series Landcruiser. If you have a turbo bolted on, whack on an Exhaust Gas Temperature guage as well, preferably measure pre turbo.

That will also show you how efficently the thing is going, and deciding on 4th or 5th gear when loaded, travelling an incline.

When I had the 1HZ in my 105 series, and towing a van etc, any sort of incline and generally it was better to drop to 4th gear. I still maintained my road speed, but with less or static EGT's....ie..less fuel being burn't and ending up as heat and not torque.

4th gear is also 1:1 ratio, so no torque loss/division of the engine torque from the flywheel thru the gearbox, as compared to using overdrive/5th gear.

Remember that as you go down your gears you actually multiply the engine torque, hence your vehicle has more punch in it in 2nd than 5th gear...right..?

Nobby I have a 2002 Troopy which now has, at considerable expense, the stronger H!50 (turbo) gearbox instead of the original R151 box.

The reason for this is that 5th gear in the old box started to stick a couple of times and that is a standard message of imminent failure. You can read about it on LCOOL.

Without knowing for sure I'd tend to assume your gearbox is the same as my old one which had done 250k of mostly bitumen kms.

Overdrive gears are weaker than 1:1 gears. The R151 is known for its relative weakness. You've just significantly increased the output of the engine and with 1400kg extra mass to pull, everything in the drive train has to work harder.

If I were you I'd be very discriminating about when and how I used 5th if towing.

Cheers
Mark

A few years ago I completely stripped 5th gear on my Patrol when towing my camper trailer to Adelaide. There was a strong headwind that day to make matters worse.
It was after this that I was advised that the 5th gear was only an overdrive and was not as robust as the other gears and further that I should only tow in 4th gear.
I have also been told that this problem had been fixed in later gearboxes by using more robust gears. I do not know if this is a fact or not.
I would definitely seek professional advice before I would risk stripping the gears.
I now have a LC100 auto.

Totally agree with Gnomey,2002 Troopy,250,000 kms,now has,at considerable expense,a stronger gearbox .Only ever towed a camper trailer.Barry

Why go into 5th. We found we get better fuel economy towing in 4th at all speeds up to 110. And eliminate the possible trouble 5th could do to the gearbox.