towing with automatics

Submitted: Tuesday, Oct 19, 2004 at 02:41
ThreadID: 121521 Views:5229 Replies:5 FollowUps:2
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Hi We are about to purchase a BT and would welcome any advice about towing with automatics. Do any of you tow with an auto and if so, do you have any problems with it.
Thanks Gayle and Colin
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Reply By: Noosa Fox - Tuesday, Oct 19, 2004 at 03:27

Tuesday, Oct 19, 2004 at 03:27
We towed our 21ft BT with a Toyota T/D Auto and now we have an F250 Auto and have found them both very good tow vehicles. You won't have any problems towing with an automatic, in fact most experts say that autos are better for towing than manuals.
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Reply By: Motherhen & Rooster - Tuesday, Oct 19, 2004 at 10:00

Tuesday, Oct 19, 2004 at 10:00
We tow with a Nissan 3 litre TD auto - as do a number of other members who have listed their rigs on the member list. Our model has recommended maximium towing weight of 2.5 tonne, so if we had the $s we would get something bigger. Haven't been far with it, but it tows easily. The auto makes the driviers job so much easier. Chews through the diesel compared to not towing though. If you do a search, i have started threads and got some good answers on both topics of towing with the present vehicle, and on what fuel consumption others get.
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Reply By: Deleted User - Tuesday, Oct 19, 2004 at 19:18

Tuesday, Oct 19, 2004 at 19:18
G'day Gayle and Colin,

Towing at max GCM (Gross Combined Mass) as in a 3500kg Bushtracker behind the big 3 (Cruiser,Patrol,F250) places max load on the auto. The load is seen as heat which is the biggest killer of auto trans. Most manufacturers of vehicles (if not fitted already) have upgrades and/or fitment of larger coolers to deal with the extra heat. All autos can suffer at max GCM but I mention the 3 above only because they are the ones usually towing BTs.

Patrol.
The Patrol petrol with auto gets hot and needs some attention to the trans cooling at BT size weights. This is borne out by Ernie's Patrol (NomadUsR). He fitted a trans temp gauge and was shocked to say the least at the temps recorded. In the order of 120 deg C from memory. Ernie has since fitted a large trans cooler and a thermatic fan to it to keep cooling efficiently at low speeds. This solved the problem and the trans run much cooler under tow conditions ...around 80-90 deg C now from memory.

Cruiser.

The Cruiser is an unknown quantity to me as I have no real world temp data from the Cruiser trans. I believe it has a trans "overheat" light ...consult the owners manual for details. The same principle applies here ...if the trans is getting hot under max GCM conditions it needs to be cooled to keep a reasonable service life for the unit.

F250.

The F250 has a huge cooler for its trans fitted from new as the F250 models here are SuperDuty. I have temp gauges fitted with one being trans temp. Extensive testing by myself and now Graham (FTroopCafe) have showed the F250 trans cooler, in standard form, is more than adequate.

My second gear pull up Cunninghams Gap took the trans to around 105 deg C (25 above ideal) which is ok for short periods. Graham did the hardest test so far ... nearly 1/2 an hour in second pulling up a huge range. This took his trans temp to 120 deg C ..which is only 13 degrees short of the trans computer placing the trans in limp mode. The trans control indicator light will flash and warn you to pull over now or risk trans damage at 132 Deg C. Under no circumstances take a mineral trans fluid to this temp and leave it in ...a fluid change should be performed as soon as practical.

Once Graham saw 120 deg he pulled over and cooled the trans then proceeded. This is the beauty of a gauge you see the heat build but also you see it normal most of the time giving peace of mind. Cooling is acheived by placing the trans in Park and idling the motor around 1000- 1200 rpm for 5-10 mins til you see temp drop on gauge.

Transmission life is halved for every 10 deg C above 90 deg C that the trans runs at for its normal running temp. Also ...towing at max GCM is considered heavy duty use and the "heavy duty use schedule" in the servicing book should be followed. You will probably find shortened drain intervals for the auto trans under heavy duty use.

The ideal running temp is 80 deg C and anything above 90 deg C is cause to fit some form of extra cooling.

An auto trans is much better for towing because it is a variable torque multiplying device but more importantly places the engine revs in a fatter part of the torque band via the torque converter. This is especially important in a turbocharged engine because of turbo lag and comes to the fore when taking off from a standstill.

Regards
Anthony


AnswerID: 565145

Reply By: TroopyTracker - Saturday, Oct 23, 2004 at 05:17

Saturday, Oct 23, 2004 at 05:17
G’day,
Had an interesting discussion with Lindsay from Linquip whilst test driving 6.5chev diesel converted 100series-(any hill in any gear hardly dented revs, need to do tow test then I’ll be totally convinced). When I asked about going with an auto when converting he suggested that because I intended towing heavy loads that it would be safer, less worries to stick with manual. He went on to tell me of a F250 auto owner who had his gearbox replaced under warranty after towing heavy loads. That’s probably no big deal but the story continued and the same vehicle ended up back at Ford for another gearbox. This time Ford told him no more warranty claims! He apparently sold vehicle (probably to buy manual). He didn’t have exact details of the load this bloke was towing but I got the impression he was within specs. Having said that, obviously some Boggers have no worries with auto but I felt it worth mentioning as the topic came up and I have no reason to believe Lindsay would make this story up.
Regards
Matt
AnswerID: 565146

Follow Up By:- Saturday, Oct 23, 2004 at 19:39

Saturday, Oct 23, 2004 at 19:39
G'day Matt,

If the owner was staying within the towing limits of the vehicle the transmission must have been faulty in the first place to have failed so early. Either that or the owner is fibbing about towing loads .... or thrashes the vehicle or both.

The F250 in the USA is rated to tow 5.5 tonnes conventional trailer and a massive 7 tonnes in 5th wheeler form. A lousy 3.5 tonnes max allowed here (til recently) will not harm the transmission beyond the slightly shortened service life because of towing ... verses not towing. Compared to the US tow specs my BT "at 3000kg" is a box trailer to an F250.

The biggest killer is heat as I said before and to highlight that here is an excerpt from a leading torque converter/trans builder ...

After 2 years of trial and error we have finally managed to find a way to lower the convertor stall speed of the A440F, A442F, A353F and A750 Toyota Landcruiser and RE4RO3A Nissan Patrol. We have found that this is a must before any V8 conversion is considered as using the standard convertor behind any V8 engine turns the convertor into an instant high stall. This will generate so much heat when the lock up is not engaged that the life expectancy of the transmission in many cases have been recorded on a regular basis to be as low as 100km with most transmissions lost at 5000km. You simply CAN NOT do a V8 conversion without altering the convertor.

The above paragraph is why most V8 conversion places recommend a manual transmission .... doing an auto is beyond their scope of engineering and is in the "too hard" basket. This leads to the fallacy that towing heavy loads is best by a manual trans ...but is more real to say the cruiser auto is not up to the job ...which it isnt unless modified. He's (Lindsay at Linquip) even tried to back up his "manual claim" by stating ...."Even the F250 auto is not up to the job "

Who knows the actual circumstances why the trans failed .... from one owners fight with Ford ... to Lindsay at Linquip (unable to engineer an auto for the conversion by the sounds of it) .... and to the BOG with scant details of the failure.

Regards
Anthony


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FollowupID: 843977

Follow Up By:- Saturday, Oct 23, 2004 at 19:42

Saturday, Oct 23, 2004 at 19:42
Woops ! forgot to highlight paragraph from trans builder .....this is his ..rest is mine ....

Start ..
After 2 years of trial and error we have finally managed to find a way to lower the convertor stall speed of the A440F, A442F, A353F and A750 Toyota Landcruiser and RE4RO3A Nissan Patrol. We have found that this is a must before any V8 conversion is considered as using the standard convertor behind any V8 engine turns the convertor into an instant high stall. This will generate so much heat when the lock up is not engaged that the life expectancy of the transmission in many cases have been recorded on a regular basis to be as low as 100km with most transmissions lost at 5000km. You simply CAN NOT do a V8 conversion without altering the convertor.
End ...

Anthony

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FollowupID: 843978

Reply By: TroopyTracker - Sunday, Oct 24, 2004 at 01:53

Sunday, Oct 24, 2004 at 01:53
Anthony,
If a vehicle can safely tow up to 7 tonne it would be fair to conclude that anyone who stuffed it's transmission towing less than 3.5 tonne would have to be doing something pretty wrong, or the story is BS. Maybe alittle of both. I hope I didn't seem to be knocking the F250 as I'm quite sure they are the best tow vehicle available in Australia while still being small enough for most to comfortably use as run around whilst not towing. Unfortunately my off road habits don't allow a vehicle of the F250's dimensions, which is why a V8 diesel cruiser would make a great compromise vehicle for the purpose of tow/offroad vehicle. Interesting quote form transmission bloke, was this from Linquip empoyee or another conversion specialist? I was actually discussing GM auto with Linsday when he said the idea wouldn't be good for towing. Hadn't considered using factory auto as it's not even an option in 7# series Toyota's.
Thanks
Matt
AnswerID: 565147

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