I am completely confused about wheather to using od or not when I tow 7000lbs trailer.

I had one transmission shop guy tell me as long as i was in town tow it with the od off, under 55 he said, so it wouldn't try to change into od while I was just going from red light to red light. Ok fine by me. The other day I was dropping a buddies zf5 off at a shop to get it re built and the guy there said that he turned the od off and that it put it in haul mode and that it completely rerouted the way the transmission worked. He also said that with a 7000lb load like I had, he wouldn't let it shift into od until he was going 70-75. I thought it just disable the od. I don't even go that fast when towing much less with the od off.

There are tons of old threads on here and other sites with conflicting info supporting "never use od while towing" or "just let the transmission do its job cause if it was a manual 5 speed you wouldn't ride around it 4th all day."

Does any body have any data to support for or against?
Does pressing the od button change the way the transmission functions in the other gears also. Haul mode?

 

on flat ground at speed it is ok to use overdrive. in town or on hills turn it off.
if the trans starts "hunting" between od and direct while cruising, turn it off.

 

What he said, if you have a trans temp gauge, disable OD if it starts getting warmer than normal. Otherwise just to keep it from luggin or huntin for gears.

 

Stopping the trans from hunting is what I thought the od button was for and to just gear it down so it didn't switch from 3 to od as i went over the rolling hills.

But what about the the claims that it made the rest of the gears shift different. I think he was mixing it up with a different trans.

 

I don't have a temp gauge but am planning on putting one in before it gets hot. Where's the best place for that. I don't want to take the pan off cause it doesn't have a drain valve and I have synthetic in it. I thought about installing a water temp gauge in a brass T and just putting it inline coming from the trans. It would run a few degrees cooler but it would tell me when things started to heat up.

Is there a plug somewhere I could take out and put a gauge in?

 

if i did not let mine shift into O/D until 70-75mph the engine would be probly close to, if not over, 3500rpm. at 45mph, O/D off, my truck runs about 2500 rpm.

 

I'm not really comfortable running much over 60 without od. I do have 3.55 in my rear end though but a diesel engines were made to generate there power with low rpms. Its a shame that if the trans wasn't made for the same thing.

I read in another thread that when the tc locks up that there is less fluid going to the cooler so it could cause it to heat up too.

Starting to think I can't win.

 

finitetime,
your sadly very correct about such conflicting info posted on the forums.
here is the real deal;

1.towing in OD (4th/economy) is no harder on the transmission nor converter than towing in direct drive (3rd.)
2.the TPS (FIPL for our engines/ip's) when set correctly,handles this.
(look here for details: https://www.ford-trucks.com/forums/1...ions-only.html )
it tells the E40D's brain when it needs to up shift or downshift (along with the lock state of the converter.)
3.under no conditions whatsoever have i had my trans "hunt" between 3rd and 4th gear in Maine's rolling hills.it either downshifts into 3rd or it remains in 4th with the diesel engine.i have purposely tried to simulate this common fear factor with this engine,and i cannot make it happen up to max gross.
4.there is no harm to let the transmission downshift to 3rd (or second if needed) while going uphill,and letting it up shift back into OD when your up the hill/going back down the other side.
5.if you find the trans quickly (within 1-10 seconds) shifts between 3rd and OD,this will needlessly ware things out and likely generate extra heat.like stated however,with the grunt of the diesel engine (even when i was n/a) i couldn't make this happen on purpose.
6.the E40D has no tow/haul mode.the OD cancel button,is just that.it locks out OD and has no effect on the converters lockup or unlock state.this can be handy to help aid in slowing down while on decent of large hills when loaded/towing,or when you know another large hill is coming right up,you can hit it to get the rpms up.however most of the time,when im headed for a hill,im giving her plenty enough fuel that she kicks right down into 3rd anyway on her own.

in summary;
do not fear towing in OD.locking out OD when towing in general,is just a waste of fuel.
there is no tow/haul mode with this trans.

 

That's what I thought but after 2 guys who build transmission told me differently and told me 2 different stories, I had to wonder.

My trans really doesn't hunt in that sense. I was refering to when you are on hills and trying to maintain a certain speed that is low enough to make it want to down shift when climbing hills but shift up going down them. We have a lot of back roads around here with 45mph limits that all up hill and down hill with a few 90 degree turns in them. I prefer to lock the od out so it doesn't shift twice every 8th mile.

I actually used that thread when I set the fipl after changing my injector pump. Thanks

I do have one question about the fipl settings I have seen the ranges suggested from 1.2- 1.5 to 4-4.5 Yours 1.2 to 4.5

When I set mine I took the middle road and went with 1.35. That only let me get to 3.8 @ full throttle. I wasn't sure what to do about it or if I needed to do anything. It hits a screw on the injection pump that looks like a rev limiter so I just left it. Do I need to adjust it?

 

I knew the one about changing line pressure and shift times was wrong, thats tech way later than the IDI's. Most modern tow/haul are just OD lock outs and dont do anything special. Ideally you do want to tow in direct, but it doesnt matter much if its adjusted right as it will downshift when it needs to anyway.

If you really want piece of mind, pick up an aftermarket transmission module. For example, Banks Trans. Command. Dont forget a nice tranny cooler, i would suggest one of those even if you dont tow.

 

your describing the roads i drive on,and with today's fuel prices,i have no complaints about letting her go back into OD asap down the other side of them hills.you have nothing to fear about letting it shift back and forth like that.that does not fall under the "gear hunt" description and will harm nothing at all.that's how she's supposed to work.
you've let people posting incorrect info on the boards instil fear about letting your auto be an auto.

i would try and get to the closest revised bulletin 186A as you can.paying 0% attention to other suggested TPS settings.
note this line: "Remove original # 186 from your files and replace it with this revised bulletin. # 186A."

they are actually very special.the one in my old mans '08 6.4l SD is incredible!!! auto OD trans have come a long way since the E40D.
far more than a basic od lock out.the computer monitoring and how it works is just amazing really, for extra grunt and braking.you would all love that tow/haul mode on the new trucks.even die hard manual fans would like that stuff.it's impressive.

 

I have no files just book marks for threads with good info. I have a ford folder with a e4od folder in it, a fipl folder, etc

The screw on the injector pump came set by the seller so I assume it is set correctly so I guess i will hunt for a wiring problem.

Until i find it though if you had to chose between having it at 1.2 on the low end and low voltage on the high end or 4.5 on the high end and leave the voltage high at idle which would be better.

 

it takes some time.but you should be able to get 1.2V idle -that one is a must.
while at the same time,getting over 4.0V WOT.
it's a bit tricky,but loosen both larger bolts and spin them each up/down.you'll see while the rear is downward,you can hit 1.2V idle,and while it's upward more you can do the same while spinning the front/each-you know what i mean,you've done it lol.however only one of these sweet spots will yield 1.2/4.0+ i think the best i could grab was 1.2/4.2? 4.3? iirc.
take your time.it is very much worth the effort. your trans will be much happier,and you'll enjoy it much more too because it'll shift and downshift like a dream.

 

Actually as HDXLT mentioned, they work pretty good. Changes shift points and characteristics. With tow/haul on my truck, if you're going down a grade and it senses overspeed, it will actually start dropping gears to slow you down.
I don't use it because it is really harsh sometimes. The tap shifter works better, IMO.

If I break over the top of a 6% grade at 60 mph with my 5th wheel, I will drop to 5th (auto, an .82 OD) with the exhaust brake on and touch the brakes one time to hold my speed. Really nice for towing. Plus with a 5" straight pipe, it sounds really mean on the exhaust brake with a good load behind it

When I had an E4OD behind a PS, I always towed in OD as long as it didn't lug and would hold that gear without hunting.

Jason

 

It's true it doesn't bother the tranny to tow in OD, but your engine might not be happy.... when you tow, you need to keep RPM's up to keep EGT's down. If you tow heavy lugging around 1500* you'll heat things up to much.