Towing in 5th gear

[ped cairns]

Hi
i have a 2002 3l diesel rodeo. It is only rated to carry 1800kg but it tows 2ton easily around town and highway but has a real flat spot down low before turbo kicks in at ramp i slip into low range and dont even notice extra weight from boat up ramp. As for 5th gear i havnt noticed any problems with mine but i try not to load gearbox upand change down early.
A couple of boys at work have and had petrol rodeos and complain about fuel from just running around town let alone towing. they have used my car and cant get over difference in fuel use
but how far are you towing not a issue if its only for 30 minutes every weekend and if you have commodore i would guess it would be similar use i dont know though.
Ped

[murf]

I spat 5th gear out of a 2.8lt diesel D/C Hilux 97 mod 160,000km, $1600

was very careful not to load it up in 5th when towing but it still flexed it out of shape

now in the GQ Patrol I will cruise in 5th but prefer to go down to 4th (straight through shaft gear) for any up hill load

cheers Murf

[RJ5023]

G'day CK,

Reckon you might be better off with a dual fuel auto mid size 4wd - something like a Pajero or Prado.

Get the best of both worlds. No turbo lag, no spinning the wheels on the ramp, lot of room for kids and junk, more range for trips to Whyalla or wherever, and can get a subsidy to install LPG if it hasn't already got it.

One of those Mum's taxis from two-four years ago would seem to be a good pick. Doesn't matter if it's a top off roader or not - you only really need reliability and the tow capacity with a tough drivetrain.

For what it's worth, that's what I'll be doing - if I ever find my new boat!

I've used TD Patrol, Toyota Hilux diesel, 3 ltr Pajero, V8 Commodore, Nissan Skyline and even a Volvo as well as bunch of others as a tow car in the past - and now an Xtrail. For mine, auto petrol wins hands down and LPG makes it even better.

From my experience, diesel can't be beaten for really long trips, but it's a pain in the butt otherwise - expensive, noisy, service costs, turbo lag on manual boxes etc - but maybe I'm just out of touch with the latest gee wizz diesel versions. (although everything I've read about DPF and regeneration just gives me the willies!)

Cheers,
RJ

[thylacene]

The manufacturers recommend that you do not tow in overdrive for a number of reasons.

As described earlier, 5th gear in a manual is usually running on a layshaft, and does not have the same amount of bearing support. As 5th is usually an overdrive, its use when towing results in the transfer of torque from the differential to the gears in the box, this torque can cause the gearbox housing to "stretch" under load, causing premature wear on gear faces, bearings, and causing fatigue in the housing leading to eventual failure.

Automatics add another level of complexity. An automatic box uses the torque converter to pump transmission fluid at pressure at a designated rate to provide torque coupling, cooling and lubrication. Using overdrive transfers load onto "lighter"gears used for the overdrive, can load up the solenoids used to control electronic overdrive and torque converter lockup. The reduced rate of flow using overdrive (due to lower engine revs), and the increased load due to towing result in significant amounts of heat being generated inside the gearbox. This is evidenced by the fitment of transmission coolers as a part of the "tow pack".

All of the above can lead to premature mechanical failure, and in the interests of avoiding unwanted warranty claims and litigation, the manufacturers provide these warnings in good faith.

That said, the manner in which you use your gearbox, be it manual or automatic, can significantly alter your fuel consumption when towing. Consider that your fuel economy is always calculated as an average for the distance you travel, and that for every return trip, there is as many descents as there are ascents.

The use of 5th gear or auto overdrive should not result in mechanical damage if used sensibly. If the weight you are towing falls well within the maximum towing limit for the vehicle, and you are running on the level or a gentle descent, the use of the higher gear will improve fuel economy as compared to running in a lower gear, as long as the engine feels comfortable (not lugging or loaded up).

Being prepared to sacrifice 5-10 Kmh can also make a huge difference to fuel economy, 25% in my case, by travelling at 95 to 100, instead of trying to maintain 105 - 110. The wind drag is the big factor here. Our 540 Quintrex is 800mm higher and 650 mm wider than our Subaru Outback, this is a very large parachute to be dragging.

Driving around town we get 8-9L/100Km, towing from Canberra to Batemans Bay and back, we average around 16.5L/100Km. There is a relatively steep descent/ascent involved going down/up Clyde Mountain. The car is rated to tow up to 1500Kg braked, the boat on the trailer tips the scales around 1250Kg with fuel. Fuel consumption running level with no headwind at 110Kmh is around 21L/100Km and reduces to 15.5L/100Km at 95Kmh using 5th gear, these figues increase by 3-4L/100Km using 4th.

When I look to replace the Outback when the lease expires I will be looking at something just a little bit larger, but will still try and stick with a "domestic" rather than industrial (SUV/Truck) for the day to day fuel economy. The difference between the two types is primarily the final drive ratio, with industiral vehicles usually having a higher final drive ratio (which is acutally lower gearing) meaning the engine revs higher than a normal car at any speed. The converse of this is that the overall drivetrain in the 4WD/SUV/Truck is stronger and better able to cope with towing. If you get a chance, go look around the car wreckers and talk to the independant transmission service specialists. Most will be happy to tell you what to avoid and offer advice to minimise damage.

So to answer your question, using 5th gear in a manual is fine if used sensibly, using overdrive in an auto is a bit more risky, make sure that you have a good tranny cooler fitted, and that the box is serviced regularly (tranny fluid degrades under extreme heat/pressure), and used with appropriate commonsense you should get by.

If looking to choose a vehicle, you need to consider all aspects. Work out what could fit the bill, then before you buy, talk to some people that own that make/model and get the lowdown before you make a decision to hand over the cash

Hope this helps

Cheers

Thy

[ozscott]

Re the above LPG - good idea but I have found that the LPG whilst providing extra tow torque at low revs is better for being used when not towing. I say this with a 1995 V8 LPG Auto and a 2002 Manual LPG - Discoveries. Towing heavy weights like 2 ton you find that up steep hills and accelerating from the stationary the venturi effect of LPG means that it tends to draw more than it actually needs...and becomes inefficient compared to petrol. Having said that I am hanging out for Liquid Propane Injection to become more mainstream (HSV are fitting it now to their vehicles) which provide amazing results and no converter to goo up with black crap. It also provides seemless shutdown of LPG over certain revs (4000 in HSVs) and full throttle where in both those conditions it runs petrol and then switches back to liquid propane injection (of course "propane" in Oz is still that unfortunate mixture of propane and butane).

Cheers

PS. I love LPG but I find now that petrol towing is probably the pick although if you have long straight flat sections then switching to LPG makes sense when towing heavy

[Coontakinta]

Some informative reading there guys. Thanks very much.

For me, at least at this time TD's are out. The associated costs with them when something goes wrong rules them out all together at this point and standard diesel. Well.....they are just too slow for me.

The rodeo in question is a TF in immaculate condition and with plenty of fruit. I know its history also hence my question being based on them. My intention would have been to fit gas to it to help lower travelling costs. A GQ is another option I'd consider if I could find one I was confident in at a reasonable cost. I dont neccessarily have to get a 4x4 as I dont use ramps that require it. Well not always huh RJ ??? But I like the security towing with the Rodeo or similar vehicle provides. That is, it feels better in the truck than it does in the commodore and is way better than when I was towing with VL.

Thanks again for all the advice. I think I have plenty to investigate before settling on a vehicle.

[ozscott]

Mate - I had a VH with a very hot blue motor 6 (yellow terra recast ported and polished head, 3/4 Sig Erson roller rockers, large valves, double valve springs, balanced, bored, billetted pro cam you name it) and it was fast...but not a tow car even when standard. I have been in VLs and turbo VLs (BTW my VH naturally aspirated left the turbo nissan 3.0 VL for dust...) and they are not tow cars...basically they were just too revy and too light. In reality they were not much heavier than a torana. But I liked those holdens before the VN blow out.

Cheers

[walruss]

Just to throw another one into the mix. I had for about 6 years a 100 series Landcruiser manual on LPG. Six cylinder not the eight. I towed with the boat - 2.5t Haines- in excess of 25000k, including one trip from Melb to Cairns return.

Never had a problem at all. used 5th gear consistently but as others have said, never whilst under a great load.

As for LPG we averaged approx 20l/100k on LPG, sitting on the 100+km/h. On the Cairns trip this worked out about $1000 cheaper using gas than petrol!

Normal driving with the gas was easy and economical.

Just some more food for thought.

[ozscott]

Fair enough Walrus...in my case the V8 rover 02 (fuel injection courtesy of BMW 7 series V8 on those) is very economical towing on petrol, so I just didnt get the big gains on LPG when towing.

Cheers

[RJ5023]

CK,

Pretty cool to watch the smoke from the wheelspin on the VL on the ramp.

Forgot to answer your original question. I always towed in 5th with the Patrol and the Hilux, but not with any of the other vehicles. Even used 4th in the TD Navara on anything other than dead flat roads.

Wouldn't tow anything in the Xtrail in 5th - ever. Patrol was useless for retreiving on a ramp (turbo lag) - used 4L just to get the thing moving without burning the clutch - and that's where you can't go past an auto transmission.

Huge difference in economy (as others have said) between 95km/h and 110km/h regardless of which gear you use. Boring as hell though!

I've read where users are reporting that the latest LPG systems (Liquid Injection?) are producing the same power/economy as petrol. (one bloke even said more power with the same economy)

Good luck with it.

Cheers,
RJ

[ozscott]

yes mate - its liquid injection...just coming to the next big thing in Oz...and its the tits

[White Pointer]

G'day again,

I (like others) assumed you were looking at a 4x4 Rodeo as your boat tractor. It would seem that it's a 4x2 and I urge caution. The LSD on Isuzu/Holden utes is very slow. Pulling a 5M plate boat up a wet ramp may not work. It will not work with my 6M plate boat on even fairly gentle, well made ramps, including Mooloolaba and Scarborough. There's just not enough weight on the back axle to get and hold traction.

Test before you buy.

Regards,

White Pointer

[Coontakinta]

Thanks WP. Yours and others assumptions are correct and a TFR9 Rodeo 4x4 was the basis for my question.

Couldnt agree with you more on the 4x2 advice and believe this to be the case with almost all utes. Wagans and sedans dont suffer to the same degree due to the location of the fuel tank putting weight on those back wheels.

Again, thanks to all. I have much to consider.

[BigE]

RJ OZscott is correct the new injected LPG kit are the "TITS" I have one on a 2.7 hilux same power as the petrol and the same KM/L as petrol ... 47c a litre for gas and $1.20 for petrol , I laugh every time i fill up and buy a coke for less than $30 have noticed the gas has more punch at 80-110kms in top gear but petrol has 10kms more top end (flat out ,,, only did that once) i think that was because of the LPG injector size. anyhow I'm happy .... similar results to walruss towing to and from bowen at easter saved heaps on the return trip using LPG only easily 1/2 the fuel bill.

Regards
BigE

[ozscott]

BigE - is yours vapour injection...I thought that the liquid injection was meant to use the vehicle's original petrol injectors...thus keeping those injectors cool and clean?

Cheers mate