towing with the OD on.

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I have read what seems many posts on other vehicles that towing in OD is bad. I have been towing my trailer that weights approx 4800 with the OD on and have had no adverse a or e ffects, am I on the short road to trans death or not?????
 

Brentbba

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I leave mine on and have for four years of towing a 3500lb trailer. Why would it adversely affect anything?
 

e9999

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maybe a reference to the engine bogging down if it does not shift down?
or less cooling of the ATF at lower rpms?

I would not worry too much over that one
 
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I would think you would be alright leaving the OD on as long as you aren't having constant hunting between 3rd and 4th gears.
 
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firetruck41 said:
I would think you would be alright leaving the OD on as long as you aren't having constant hunting between 3rd and 4th gears.

This would be my only concern, but if you are rolling at it isn't shifting constantly, I'd think you are fine.
 
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trojan_knight said:
i keep the o/d on. i have found that the tranny can over heat if you turn on the ECT becouse the torque converter clutch wont lock up.

I may be wrong on this, but I thought the ECT button and the O/D buttons were pretty much unrelated. The ECT just changes the shift points, while the O/D disables the overdrive.

That being said, I have always thought that it would be a good idea to disable the O/D while towing-- under the theory that the O/D is the weak link in the tranny. But I don't think I considered the fact that without the O/D enabled the torque converter would not lock up.

So now I am not sure what I would do.

When I asked this same question, it seemed like most people said you would be better off turning off the O/D while towing.

Jared

PS--Here is my thread on the subject

https://forum.ih8mud.com/showthread.php?t=48787

CruiserDan tows a boat all over with his 80, and he turns it off-- so I say do what he says

Actually, now that I reread that thread, maybe I was misquoting him. I am going to start towing a larger boat next summer, so I would like to know the definitive answer on when to use, and when not to use the O/D when towing.
 
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Always run with o/d off when towing in my 80.

The torque converter remains locked at lower rpm/speed when the OD switch is off which results in cooler tranny temps and therefore better for towing. I've tested this going up hills in 3rd with OD on when pulling about 3200 rpm and turn off the OD the torque converter locks and RPM drops 3-400.
 
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I say leave it off except on long straight downhills or when you have a tailwind.........







A tranny can only shift so many times before it breaks........




sooner or later, but later is better.

Dan
 
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I also tow with the OD on, but before putting the S/C on, it would do a lot of hunting on hills. I found if I manually shifted the OD on and off in anticipation of hills, I could reduce the hunting and hopefully spare my tranny from excessive shifting.

I think with a stock engine, if your tranny is not hunting for gears, then you're okay with OD on, but if it starts shifting a lot, you may want to turn off the OD.

With a S/C'ed engine and the OD on, I can't recall it ever hunting even on hills. That's why I leave it on all the time now. The engine does run cooler with the OD on vs off when towing (as judged by EGT's); don't know about the tranny.
 
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cruiser ken said:
Always run with o/d off when towing in my 80.

The torque converter remains locked at lower rpm/speed when the OD switch is off which results in cooler tranny temps and therefore better for towing. I've tested this going up hills in 3rd with OD on when pulling about 3200 rpm and turn off the OD the torque converter locks and RPM drops 3-400.
Just to clarify-- you are saying that the torque converter will lock in third gear with the OD off? Do you know what RPM's this will occur at? Does it matter if the ECT switch is turned on or off?

Someone should write a book about this.

Jared
 

woody

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by the end of 2005, I'll have over 9000 miles of towing with my 80...all hauling my 3800ish# FJ40 around on a 1500ish# trailer.

I hit the ECT switch to change the shift points, and generally pick either OD or 3rd with the selector switch...as soon as the tranny begins to "hunt", it gets manually put in 3rd. The RPM's drop by 2-300 and it goes into lockup mode. Once I crest the hill and my speeds have resumed, I manually push the button to put it back into OD.

If you watch your tach while in OD, you'll occasionally see your RPM's increase by 2-300, meaning it's kicked out of lockup....when I catch those, I immediately shift into 3rd.

I tend to avoid cruise control if the terrain is at all hilly....while I lose speed on the hills, it's less likely to drop hard into 3rd...

my "last" towing trip for 2005 is this coming weekend, 300 miles each way to Attica. The prior trip was 1000 each way to Oklahoma, and the 80 performed excellent as a tow vehicle. It's NOT a hill climber, but get a decent draft and it will hold it's own.
 

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