60 Series fifth gear.

5th gear is not that fragile. I did 320,000 in a 60 series with the hardest work towing a 2 ton fibreglass ski boat behind. It did finally let go but it was not the 5th gear that went. The main shaft blew up and damaged the whole box. You should be able to load up a 60 series and do the whole of Aus in 5th without a heavy trailer no problemo. They are pretty tuff.

Justin I Have had 2 60s and done a combined distance of about 300,000 and to date not had a problem with the 5 th gear . But i have never towed any thing but do have a full load of gear and a family of 4
All the best
Eric
4wd Tag Along AdventuresCape York Connections

Hi Justin,
Agree totally with the other replies!! I have just done the 'Top End & Gulf fully loaded, & camper trailer with tinnie on top, all up just on 4000kg. No probs. at all.
I was surprised at how well the 'old girl' went [non turboed] just keep the revs up. I reckon at 95-100kph. in 4th you would need a bloody good sterio!!!
Have a good one
Phil

Hi Justin,
That is an interesting question. I am no scientist nor a mechanic but my way of thinking would be that when the vehicle is loaded to the gunnels(gunwhales) the weight is positioned over the gearbox. So when you have reached a cruising speed you could quite comfortably select 5th gear and cruise. When you are towing however, you are putting lateral strain on the drivetrain in a pulling motion and as the 5th gear is more of an overdrive coasting gear, this would be detrimental to the strains which the gear would have to endure. I find that I do this quite often without thinking when towing a trailer full of rocks or gravel. It is far better to be on the safe side and to desist in towing in 5th gear. The damage may not be done now but you could have gearbox failure when you least expect it. Happy travels!
Cheers,
WillieNever a dull moment

This very issue was put to me also. I searched through the owners manual and no reference to not towing in 5th. I have a current model 3.0TD Hilux and infrequently tow a pop top van weighing say about 1400kgs. The g/box shares the same part number with the normally aspirated diesel in the 100 series. I don't load up 5th and use 4th where inclines are involved otherwise she is quite happy at 95 to 100kph. I am hoping this will keep everything together. It is certainly a better tow vehicle than my VT 8cyl Commodore. Does anyone have any contrary views or experiences regarding the use of 5th gear on a Hilux??

5th gear is used when you get enough momentum up to move into it. Your vehicle is under different loads all the time. The logic of not using 5th gear is just the same for the others. When the gear starts to labour [or better... just before] you change down gears. No mystery. No problem. Cheers RoyceRoyce www.funshow.com.au

Have a look at post 6958. I posed a similar question and received some interesting answers. Obviously two schools of thought out there although I note that any technical answer is invariably on the side of not using 5th for towing or hauling heavy loads.

Justin, there is nothing fragile about 5th gear in a 60 series. Gearboxes are designed to accomodate the expected torque input from the engine. As the gears are changed up the torque output from the box is reduced so that when 5th is engaged the available torque at the output shaft is reduced compared to the motor. However the layshaft which drives 5th is rotating slower than the motor so this is under potentially greater stress. I think the issue of 5th gear failure is lack of lubrication, re the seal leaking into the transfer case. I would like to hear about a L/C 60/75 gearbox failure that didnt include lack of oil.
cheers haze

This is how it was explained to me from someone who bought a 1yo hzj 75 pc with a worn 5th gear .The Landcruiser 5th gear is quite small and towing a heavy load in 5th will cause the gear to heat up and because of the small surface area it can not shed the heat quick enough.It goes without saying that it also heats up the gearbox oil. This causes the chrome on the 5th gear to come off.I asked a gearbox rebuilder who did my Dyna gearbox which is similar and he agreed with the "too small theory".Modern 4wd drive engines have much more torque than their ancestors but the transmissions have not increased in robustness proportionately. Old 4x4s usually bogged down trying to tow in top gear and you had to change down
I dont see any problem on towing a light load but obviously you have to make allowances as the load gets heavier and the terrain becomes hilly.It is far better to let the engine rev(a landcruiser runs ok at 100klm in 4th) than strain the box .It is much cheaper especially a long way from home.The same rule applies when offroad ,its better to use a gear thats too low rather than one thats too high