No towing in 5th gear

[Bullant4x4]

Ok, I know they say don't tow in 5th gear as this gear is at the back.....etc etc. But I'm just wondering what is worse or best.

Now the patrol (3.0 diesel, manual) can do 95km and 2500rpm or 96km in 4th with revs at 2700rpm. If I push the 100km it goes to 3000rpm. I'm trying to save fuel, not thrash the engine so on very flat areas and down hills I throw it into 5th so I can travel 110km. Is long hours at 3000rpm giving the engine a hard time?

So what do you think is better, higher revs but still use 4th or lower revs and use 5th on the flat/down hill bits? Or suck it up and travel 95/96km everywhere

I just spent coming back from Grampians at 95km except for the flat/down hill bits and almost pulled my hair out.

[Joff]

I tow in 5th all the time but I know that some boxes don't like it. I can't see why 3k should be an issue and frankly I'd rather be stiring the box to keep my speed up than sitting on 95 everywhere. That'd do my head in.

Indecently, if I recall correctly, the 5th gear in that box lets go at the spline, not the gear, so it is conceivable that you can could just drive it in the most relaxed way and if the thing does go bang you can still get home. Just have a spare box ready 

[neowatcher]

First of all, look at your manual. If it states that you should not be towing in 5th gear, then you probably shouldn't. If your fifth gear is the top gear, it is probably the over-drive gear. That is designed for cruising (constant speed and no towing/load). You would probably notice that fifth gear is pretty gutless and an auto would simply kick back to fourth when you put your foot down of have to climb a hill. A fourth one is more powerful in that respect.

Towing in fifth may heat up the gearbox and puts too much strain on the gearbox (you may be able to check that with a scangauge or so). Even though it is doing less revs, it may need to work harder than a fourth, and in that respect towing in fourth may actually be more economical as it spins the gearbox more easiliy and keeps the gears lubricated and cooled! I have seen a post of someone getting really good fuel economy after towing in fifth ... on the back of a tow-truck

Having said all that, I usually only go to fifth on down-hill and sometimes on really flat stretches on constant speed. As soon as I see a hill or I hear it is trying to work harder, I kick it back to fourth. Sometimes, I don't bother at all and just keep it in fourth, doing just 90-95.

[Joff]

The actual reason for the 'thou shall tow in 4th' dogma is that in 4th traditional gear boxes transmitted torque straight down the main shaft from input to output with loading any gears. They only load dogs. I have no idea if modern manual boxes work like this. Modern auto's certainly don't so i think, like most things these days, one shoe doesn't fit all.

[rotare]

There was an argument on another forum regarding towing in fifth with a certain brand of vehicle (not Nissan).  Those opposed to the towing in fifth claimed the 'fifth' gear arrangement in the auto trans was weak and could likely break.  However there wasn't a single example on the forum where someone had physically broken the fifth gear, output shaft or any other component of the transmission from towing in fifth gear - so the theory didn't appear to match the reality in this case.  The vehicle in question has been on the market for over a decade, however sometimes facts don't seem to matter when there are strong opinions involved.

I often towed in fifth gear and never had a problem.  However, with my latest vehicle (NW Pajero) I fitted a scangauge plugged into the OBD port that I use to monitor transmission temperatures.  What is very obvious is that when driving in fifth gear up long hills, even when not towing, the transmission temperatures can rise very quickly.  Not hard to exceed 100C temps without trying, and I'm running two large external transmission coolers as well.  Made me wonder how hot my transmission had got in my previous vehicle when towing in 5th for extended periods in hot whether with the car loaded and with the family onboard.

For the longevity of the trans oil, and transmission, everything I've read suggests to try and keep the transmission oil below 100C when possible.  Towing in 5th with the Pajero under load (ie, into a head wind, up hills etc) it's impossible to keep the temps below 100C because of the convertor slip.  In these circumstance I drop it back to fourth, then back into fifth / drive on the flats and just keep an eye on the temps.

I guess in my experience there isn't an issue with the strength of the gearbox to tow in fifth, and the issue isn't whether the car has enough grunt either.  But what I've found is that the transmission temps skyrocket, even when using fully synthetic oils.

Hope this helps.
   

[Footy Shorts Shane]

Now the patrol (3.0 diesel, manual)

If that was my vehicle, I wouldn't tow in 5th gear.

Shane.

[edz]

I would temper the tow / not towing discussion  in fifth gear with needing to know the all up  trailer weight you would be towing .

[brickiematt]

FWIW, I always tow in 4th with the Paj. As rotare said, in 5th the torque converter is constantly locking and unlocking, driving the transmission temps way up.
4th is constantly locked, and it's quite amazing the difference in temps this makes.
Running a few hundred RPM higher doesn't bother the engine or me,  but i will knock it up to 5th occasionally on long flat stretches or gentle declines.
Works for the Paj, may not work for others.
 

[Bird]

If that was my vehicle, I wouldn't tow in 5th gear.

Shane.

I'd sell it.

[GeoffA]

...
So what do you think is better...
...

Use 5th...

[GeoffA]

I'd sell it.

 

[tk421]

If you've got a manual with fifth gear overdrive arrangement, don't tow in 5th...

https://www.youtube.com/watch?v=M4Vpr7JMf_w
https://www.youtube.com/watch?v=1BLkLpICIOs

For an auto - do what your manual says.  Mine says, "Don't tow in 4th'
Heat kills autos. For most auto's, If you're driving up hill its going or into a head wind the tranny is going to be constantly jumping between torque converter lockup and unlock because the ECU doesn't understand you are towing - this locking/unlocking process generates heat.

I run an Ultraguage, and have tried towing in D vs 4th. In D the temps can rise rapidly as you climb a hill (even on the flat), drop it into 4th and down it goes. 

[KeithB]

I put a Richards Transmission Lockup Kit on and it immediately reduced transmission temps by 20-30 degrees.
Keith

[listo]

I use fifth with my 5 speed manual every time. Maybe I'll learn my lesson the hard way one day but I haven't done a gear box since I was a young feller driving like a knob.
My figuring is if it can't tow a 4.2m boat or a camper trailer it's not worth having. In saying that, I have the mechanical knowledge of a cardboard box, so maybe my advice should be taken with a grain of salt 

[Bullant4x4]

I tow in 5th all the time but I know that some boxes don't like it. I can't see why 3k should be an issue and frankly I'd rather be stiring the box to keep my speed up than sitting on 95 everywhere. That'd do my head in.

Indecently, if I recall correctly, the 5th gear in that box lets go at the spline, not the gear, so it is conceivable that you can could just drive it in the most relaxed way and if the thing does go bang you can still get home. Just have a spare box ready 

Thanks for the info!

Update :-

The 2013 Patrol 3.0 Diesel Manual, GU9 has an updated gearbox and has a strengthen gearbox spline. This means that it can handle the abuse and if it does fail the spline on 5th gear will go, leaving you able to use all other gears.

There is a drive-in, drive-out extra plate that can be added to stop 'IF' it twisting but has all other upgrade done to it.

Been told they can handle a "sh*t load" but always a ? No gearbox rebuild person will tell you it is OK but many do it without problems?

Still interested in others option.

[tryagain]

I don't know much about patrols other than the 3.0L doesn't have the best reputation so chances are the engine will go before the box, other than that go with what the manual says.

[Bullant4x4]

I don't know much about patrols other than the 3.0L doesn't have the best reputation so chances are the engine will go before the box, other than that go with what the manual says.

Manual does not  mention anything about gearing while towing.

[Coiled]

I tow more than 2T, have done since it was new behind my CRD Patrol manual and it lives in 5th. So far no issues after 65k with probably 70% of that hitched. Motor still going strong too

[TYMEUP]

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[slydar]

  Towing in 5th with the Pajero under load (ie, into a head wind, up hills etc) it's impossible to keep the temps below 100C because of the convertor slip.  In these circumstance I drop it back to fourth, then back into fifth / drive on the flats and just keep an eye on the temps.

have you considered getting a manual torque converter lock? there are plenty of home-made designs on forums like this one, and a place in Melbourne sells one you can install yourself - and before anyone runs out and buys a switch there's more to the technology just tapping into the wiring and connecting the switch to the torque converter lead - it will burn out the locking solenoid in no time

[rotare]

have you considered getting a manual torque converter lock? there are plenty of home-made designs on forums like this one, and a place in Melbourne sells one you can install yourself - and before anyone runs out and buys a switch there's more to the technology just tapping into the wiring and connecting the switch to the torque converter lead - it will burn out the locking solenoid in no time

Yep, made my own lock up kit on my previous Pajero with $10 of resistors and relays.  The new Paj has a totally different gearbox though (more electronic trickery) and from what I've read from those that have tried a lock up kit from Wholesale transmissions on these Pajeros it has been hit and miss.  At this stage I'll wait until they get it sorted before I make / buy a kit for this Paj.

[Jason B]

Same story I have herd with my vehicle, I tow in 4th if climbing or on flat ground into a head wind. If the going is relatively easy or down hill I always grab 5th. Long periods under full load I try to avoid in 5th, but I do use it a fair bit otherwise. So far so good.

[GeoffA]

That's fixed it.....

[TYMEUP]

Sure did.  Has been over 12 months since we did the job.  Stronger than its ever been.  Wasnt towing at the time either, dont know history of vehicle though.  Could come at 5k to rebuild.

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[GeoffA]

Sure did.  Has been over 12 months since we did the job.  Stronger than its ever been.  Wasnt towing at the time either, dont know history of vehicle though.  Could come at 5k to rebuild.

 

A brand new upgraded shaft and gear will cost around $350 from Nissan. Add bearings, synchro's etc.
A complete late model used box is around $500-$1500, depending where you buy.
A reco box will set you back $2000.
A brand new complete box can be had for around $2600.

It's not an issue that's worth worrying about really.....