auto gu patrol

Submitted: Sunday, May 18, 2008 at 20:23
ThreadID: 57740 Views:2459 Replies:3 FollowUps:4
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i have recently bought a 06 gu 3l auto diesel patrol . my last 4wd was a 80 series lc diesel. i tow a boat which weighs about 1500 kg. can someone please tell me how i should be driving ? should i have it in overdrive with power button on or should i have overdrive off power off ? the auto bit it is new to me cos the lc was a manual . it feels like it is struggling compared to the lc. most of the towing is done on flat roads between adelaide and port victoria. also on a recent trip back from the peninsula with cruise set on about 85-90 i was getting 15l per 100 kms towing is that good i was expecting a bit better thanks for all your help
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Reply By: stevie1947 - Sunday, May 18, 2008 at 22:16

Sunday, May 18, 2008 at 22:16
Rule number 1. Never tow a substantial weighted trailer, van, etc in overdrive, especially up hills. The overdrive bearings are only small and will "chew" out, causing a very costly repair job.
I would only tow in overdrive if I was going down hill with a tail wind.
AnswerID: 304599

Follow Up By: chippy4 - Sunday, May 18, 2008 at 22:24

Sunday, May 18, 2008 at 22:24
thanks for your help
FollowupID: 570668

Reply By: Member - Brett C (WA) - Sunday, May 18, 2008 at 23:05

Sunday, May 18, 2008 at 23:05
G'day Chippy 4,

We travel regularly for horse events in WA with two horse. Total weight behind our GU III (which has a 3inch lift, plus 33's), is sitting at just over 2.5 tonne.

We cruise comfortably at 100kph, but when going up hill, we always drop back to 4 (5 speed manual). Otherwise it stays in 5th.

Economy best was 14.6 l/100, with the normal being just under 16l/100.

Would not have thought much different between auto and manual for cruising, as the 5th gear sits on 2500rpm at 100....maybe auto is slightly higher, but would have thought less.

I have found though with our Jayco Eagle Outback at 1.4 tonne loaded, it sits just shy of 16l/100...maybe due to it being slightly wider creating more drag. The horse float is higher but maybe the draft goes over the top more freely then when the trailer is wider??


AnswerID: 304608

Follow Up By: Chaz - Monday, May 19, 2008 at 00:44

Monday, May 19, 2008 at 00:44
The Nissan Auto sits around 2000rpm at 100km/h, maybe slightly higher rpm with standard rubber, but torque multiplication is all but gone at that speed, so unless the converter is locked it becomes a bit of a slug, and needs to be shifted back if the load is too great.
FollowupID: 570683

Follow Up By: chippy4 - Monday, May 19, 2008 at 19:25

Monday, May 19, 2008 at 19:25
thanks for your help chaz , you mention the torque converter being locked can you do this manually or is it all automatic?
FollowupID: 570797

Follow Up By: Chaz - Monday, May 19, 2008 at 22:59

Monday, May 19, 2008 at 22:59

Your torque converter will lock automatically in 3rd and 4th gear above 80km/h and in 1st gear low range with your foot off the throttle for down hill decent engine braking. I have fitted a Manual Converter Locking System that allows me to lock mine in any gear and at any time. There are manual converter locking kits available, but this one is reasonably simple to do and very cheap, only a few relays and switches. It’s really only a matter of knowing where to connect it into. A few people have copied my circuit and had them fitted by auto sparkies, and once familiar with the feature, it can be a useful improvement for towing and pulling up long hills. I wouldn’t be without it.
FollowupID: 570833

Reply By: Chaz - Monday, May 19, 2008 at 00:38

Monday, May 19, 2008 at 00:38
Hi Chippy,

The problems associated with towing in a manual are totally different to those in an auto, but some rules should still apply. An auto doesn’t have gear or bearing issues like a manual, but when towing in O/D, you’ll need to lock the torque converter as soon as possible and try to keep it locked. This is to reduce the heat build up in the converter that’s caused by excessive flairing and slippage when under heavier load, such as being in O/D. The converter lockup eliminates the slippage and dramatically reduces the heat build up.
Your car is fitted with a good transmission cooler, but it’s not enough under heavy loads, so if the converter unlocks in O/D, then you should go back to third gear and try to keep the car above 80km/h, which should allow the converter to lock again in third. If you find that the converter can’t stay locked, then you should shift down because heat is the biggest killer of auto transmissions.

I always tow in O/D if speed is high enough and I keep the converter locked manually. It makes a huge improvement to the vehicles towing ability.
AnswerID: 304622

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