Towing and R380 gearbox??

[noogie]

HI all

I just bought a Kanga Camper trailer and tare weight is 700kgs with ATM 1400.

I'm always weary when towing in the TD5 not to overload that 5th gear going up hills. The truck tows the camper no problems, but I'm just wondering when most people back off into 4th when towing?

I tend to do it on steep hills and hills that are long climbs but not really steep. Am I just being too cautious?

I intend installing a gearbox oil cooler one day soon.
Any advice on which coolers are better than others?

Cheers
Mick

[Homestar]

My old Classic spent 18 years towing either a 2.25 tonne boat or a 1.8 tonne caravan - it almost never did any work without a load behind it - and that was with the LT77 which isn't as strong as the R380.

It was never thrashed, and the Father in Law - that did all this towing - was always smooth with the throttle and clutch and 5th was used all the time, and the box never had an issue.

I wouldn't think you would have any dramas.

[Blknight.aus]

just dont bury the boot in the lowe end of the rev range in 5th, if its starting to struggle and you're below 2500rpm change down.

[flagg]

I have a turbo Isuzu 4bd1 and an r380. The general rule that it use is that I don't accelerate in 5th, towing or not. If I find myself wanting too I just change down. So far so good!

[laney]

Anything under 80kmph I drop back to 4th gear as I have killed one r380 box that really hurt the back pocket.

[Barra1]

just dont bury the boot in the lowe end of the rev range in 5th, if its starting to struggle and you're below 2500rpm change down.

That's interesting Dave

I've always figured it best to simply avoid using 5th gear when towing my boat. Mate, I'd like to hear your opinion regarding this, am I being too careful?

Even on my trips to the NT I stay in 4th at around 100kph - sounds like I should be shifting up into 5th. Keep in mind though, the Defender is well loaded as is the boat. (Yep, I know - one shouldn't load the boat but the gear has to go somewhere).

Thanks in advance Dave.

(OP - I don't mean to hijack your thread but I reckon it is relevant)

[dromader driver]

mandatory good oil cooler for an R380 anywhere north of the brisbane line. Mine gets very hot with a load on the highway.

[Blknight.aus]

That's interesting Dave

I've always figured it best to simply avoid using 5th gear when towing my boat. Mate, I'd like to hear your opinion regarding this, am I being too careful?

Even on my trips to the NT I stay in 4th at around 100kph - sounds like I should be shifting up into 5th. Keep in mind though, the Defender is well loaded as is the boat. (Yep, I know - one shouldn't load the boat but the gear has to go somewhere).

Thanks in advance Dave.

(OP - I don't mean to hijack your thread but I reckon it is relevant)

the box is rated for 380nm of torque if you dont have that in theory you cant hurt it. BUT.

5th gear is overdriven, a small gear driven by a large gear is going to get hot and its going to wear out faster...

The main reason I advocate changing down if its starting to struggle at about 2500rpm is simply the amount of time it takes to change gears, and get the power back on youll be pulling the gear at about peak torque RPM by the time you get it in.

IF you REALLY wanted to haul it up the hill you would change down even higher up the rev range so that you had peak power RPMS wound on by the time you hit the hill and then you would shift down as you hit and fell through the peak Torque RPMs however the rev range and gearing of our engines and gearboxs isnt entirely suited to this. but i digress

Torque is what gets you up hills, running in an overdrive gets you more speed but lower torque on the output shaft compared to what the engine is putting in if its direct (4th) or a reduction drive (1-3).

A boost gauge and EGT would help demonstrate it but basically

Hauling the wifes disco up the towoomba range I get about 17psi on and sit the EGT at about 625-640 with about 1.5T extra weight on the vehicle and trailer (lets call it 4.1t~ish) if I try to work it up in 5th. generally it'll sit down and hold 2100PRM~ish. If i snick it down a gear the engine comes up around 2700~ish but the boost is up to about 22-24psi and the EGT is down to 550.

very very roughly, boost indicates how much power you're trying to make and EGT indicates how much torque you're asking for.

[goingbush]

Good advice Dave, especially since Noogies Defender is chipped and has a bigger exhaust and Intercooler so the car will happily motor along all day in 5th, seemingly without any stress.

I always only changed gear according to rpm and load and never raced thru the gears , always used Syntrans and generally looked after the car but still my R380 5th gear went from quiet to very noisy in a matter of a few hundred km and complete box was cactus a few thousand km later because I made the decision to keep driving , (even after dumping the caravan) knowing that a new Ashcroft box was in the mail.

[Marty110]

Isn't the problem that the 5th gear is on a seperate layshaft which is smaller and had smaller bearings than the main? I reckon it is a good excuse to get a GKN overdrive so you can tow in 4th OD which maintains direct drive through the mainshaft and only slightly lower geared than 5th. Had this setup on my Defender and it was the ducks guts - especially that little switch on the gear knob - no clutch so you could just be under full load up a hill or overtaking and either switch up or down depending on circumstances with no loss of momentum as you would have if you had to use the clutch. The downside is you have to have your gearbox and trans well shimmed and 'tight' or you can get some serious 'clunking' at coast or over-run.