Tip # 29 from da "Lone Ranger": Saving your Automatic Transmission

Submitted: Wednesday, Mar 30, 2005 at 23:03
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And comparison on performance of Manual vrs. Auto Trans in towing:
I have experimented over for fifteen years with Automatics in rough conditions towing big vans in the Outback. Now, my experience is limited to two Toyota Automatics, and a Ford F-350 4x4 E4OD Automatic in the Outback. So, just so you know that is my “frame of reference” in this research, you have to correlate my findings to suit your own tow vehicle if different… And check with your manufacturer on the application of the synthetics I am about to tell you about… But this is very good advice for the life of your Automatic Transmission in the deserts… Nevermind the experience with GMC and Dodge in snow country as this is only about the Deserts here in Oz...

First you need to understand the “why” in this research…. Towing with automatics as a liability in the Bush, is all about heat in the transmission fluid. That is why you see the recommendations of people adding on Transmission Oil Coolers since the 1980’s, and why most towing type vehicles have those on as standard equipment now… In the 60 Series Toyota for instance, in 1987 they had only a bottom radiator oil cooler, and 1988 they had one additional exterior oil cooler in front, and then 1989 on the Sahara they put two on… This was the trend of “discovery” by Toyota with the experience of automatics put into extreme service in the Outback…

As you are slogging along in thick mud or sand or just the added resistance of the corrugation and a headwind when towing, you build up a lot of excess heat. This heat leads to excessive wear. When the heat gets to an extreme, the oil actually foams, then BANG! And you are walking…. No, it is not funny.. People were routinely overworking the automatics doing things like towing a boat in soft sand on the beach. Not paying attention to an overheating light or not having it come on, and oops!!!

So why the synthetics? Well, quite simply put, they are superior as both a transmission fluid in fluid dynamics, and also they will operate at much higher temperatures without foaming. This can save your transmission… The drawback is cost. A 20 litre Drum of Dextron II like these vehicles of mine used is about $65…. A 20 litre drum of Castrol Transmax Z, the synthetic called for in these, is about $285…. Say what???? Yes, definitely not the go for mums automatic running around town… But…. For a Beast travelling the Outback, prone to have a go in the Bush and hard slogging in sand and mud and such, with a Bushtracker on the back…. And you have a different set of values at hand. The truth is that the downfall of an Automatic is that almost no one outside of the major cities can attempt a rebuild of it…. And if they could you might be looking at $4000 and up!! That is why most Bushies on Stations try and stay with the manual transmission. But in my case my wife could not run it. A Hospital Wing, yes, a manual transmission,…… No! Also, I must say that now I am spoiled having my last three personal 4x4’s all with automatics, it sure is nice to drive one handed with a cuppa or whatever cruising along without shifting… Especially in traffic.. And the cost of those synthetic fluids is off-set a little by longer maintenance periods recommended..

I am often asked what about the auto for off-road…. Well the short answer is that it wins the muddy or gravel, slippery hill climbs hands down. In low range, most automatics power shift without a pause. It is the pause that stops forward momentum in extreme mud track hill climbs in 4x4, and no one can shift like an auto. One “Blue” with a manual and miss a gear and you are in trouble, the auto does it all with power on…. And in Low Range it actually “Power Shifts” with power on it that is just the opposite effect of shifting the Manual transmission. The only disadvantages would be in the extreme test of downhill running at a crawl. The manual has a lower gear in low range to crawl down on engine decompression, while the auto has more reliance on brakes, but this is a real extreme you are unlikely to encounter… On highway hills with engine braking, you can downshift the auto the same way as the manual, and watching your RPM’s they are much the same using the engine to slow your downhill run. The manual is better, with more gears… But it can be done to some degree with the auto trans manually downshifting as well.
NOW FOR SOME REAL ENGINEERING GUFF IF YOU HAVE THE CHOICE IN PURCHASE..… The auto advantages overall at least meet or outweigh the disadvantages WITH RESPECT TO EASE OF USE… BUT, there is a “Caveat Emptor” (Latin for Buyer Beware.). Fancy Duh? And you didn’t think the “Last Ranger” could read or write- Ha!) And that Caveat is serious in two parts for the pocketbook…. Firstly, and it is almost true across the board, the Automatic has a big price tag in terms of fuel consumption, about 1-2 Mpg in the American trucks at a minimum, and up to 3-4 Mpg. In the face of higher fuel costs this is a consideration… And secondly if the Automatic ever packs it in to meet it’s Maker, it is about a $4000-$5000 Rebuild in one of the ten largest Cities. Where the Manual has it over: Is a new Clutch, Pressure Plate, and full gearbox rebuild by regular Mechanics for about half the cost and just about anywhere. Also, the Manual will usually growl and whine and Pop out of gear and grind on you, (just like my Missus) for 30,000kms before it packs it in… It gives plenty of notice of impending failure, where the Automatic can completely quit on you with little warning…. The manual Transmission is far better for severe downhill runs, on engine braking with more gears and running to your Tacho (Engine RPM)…. But if you don’t have the manual choice, do not despair. The automatics are nicer to drive, and will last and perform well, but overworked this Tip can save you…

Sooooo, getting back to the topic, take care of your auto trans, with superior performance fluid in the synthetics, with a much higher heat range and tolerances… Good solid advice from one who has pushed them to the limits and beyond. In my testing I have replaced one Toyota transmission with extreme abuse, and one Ford transmission doing the same extreme work… Although with the Ford it took a heavy 6 horse 29 foot Gooseneck off-road to do it… A wrong turn, a big canyon, and no where to turn around at the bottom, off exploring again… Reverse gear in an automatic, overloaded in low range… I managed to kill it testing the limits… Reverse gear plates disintegrating plugging up the radiator transmission cooler, until the unit smoked… But I did make it back limping home… And then custom built up another transmission with the heavy duty towing package upgrades that are available.

I have pushed the limits way out in our own Research and Development beyond what you would probably do, and you are the Beneficiary….. So if you are planning to push the limits, take heed to the advice on the Synthetic Transmission oil…

Lessons learned hard are long remembered… Smart People learn from other peoples mistakes…. Ha! Duh….

Cheers from the “Lone Ranger” at Bushtracker
"The Last Stand In Open Country"

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Reply By: MattandLana - Thursday, Mar 31, 2005 at 10:02

Thursday, Mar 31, 2005 at 10:02
Thanks Steve, good tip.

My personal experience was cooking the auto box in a near-new GQ petrol Patrol running around in the Centre one summer - no towing but lots of camping stuff on board plus lots and lots (ie. 100kg plus) of water plus 40kg of jerry cans.

So for all you (like me) who are driving auto trannies, here's a supplementary tip from hard experience: WHEN YOU START THE ENGINE - CHECK THAT THE BULB IS WORKING IN YOUR A/T OVERHEAT WARNING LIGHT!! (That's why they all come on - for us to check!) One 20c bulb versus one multi-thousand-dollar gearbox rebuild. It's our choice.

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Reply By: Motherhen & Rooster - Thursday, Mar 31, 2005 at 10:34

Thursday, Mar 31, 2005 at 10:34
We are having a transmission temp gauge fitted to the Patrol tomorrow, and they have also talked us into having an exhaust gas temp guage fitted as well.

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