any answers????????

[F-350MAN]

Hey everybody,

I have another question. Is it better to take the tranny out of overdrive when pulling or o.k to leave it on. I had an F-150, and also had a 2500 GMC with a 454 and they both said to pull with overdrive off I was just wondering if a diesel having more torque would eliminate this. I don't have an owners manual for this type of info so any advise would be helpful. I pulled all the time with the gmc and went through 2 tranny's and started on the 3rd thats why I bought a FORD. so far so good

[overl0rd]

Towing in hills where the tranny keeps downshifting it's advisable to run it with O/D off. Otherwise on flat land I reckon you'd be fine leaving it in O/D.

[wesjones]

if it's something light like a jet ski, you're p[orbably fine to leave it on, but if its heavy like a bobcat you should have OD off

[Mike OB]

Hi Randy: Over drive or not, if you stop the cause of what kills the tranny you can do as you like. What kills all transmissions is heat! That heat is built up because the tranny slips when under load. To stop it from overheating there are a couple of things that will help. One - is to install an aluminum fin deep oil pan, second - you can add an extra oil cooler in front (the bigger the better). third there are a lot of after market outlets that make heavy duty torque converters and control units that will raise the line pressure to make the clutches hold better. or four - You can go crazy and replace the trans with a Suncoast trans. Your best bet is to keep an eye on it and smell the oil on a regular time frame, if it starts to smell burnt? your over working it and need to take some action to solve the problem. Happy trucking Mike OB

[wiwaniuk]

I'm glad you came to your senses and replaced your GMC with a good truck. In my humble opinion, GM has never had a good high-torque, low-rpm truck engine. Ford has had a long-stroke truck engine for I do not know how many years. When you tow, the low-end torque is what you are after. For me, I tow 4 tons of travel trailer. If I am flat, I will use OD all that I can. If I see that the transmission is shifting in and out a lot, I will disable OD. I have a 7.3 diesel with 4R100 tranny (is that right?) and 3.73 gear package.

[Ramsmoker]

Mike hit the nail on the head. If you have the ECM turned up you will drive thru the trans. You may or may not know when its happening but believe me, it's happening. If you notice the trans "hunting" meaning going in and out o/d you should shut it off. The other thing that happens when they shift back to 3rd gear is the T/C unlocks and locks. This is a wasted move you can only correct with a T/C lock overide switch. For years it has been said that overdrive is not as strong as direct. I just built my first 4R100 and I can tell you the planetary in overdrive is the same size as 1st.

[Mike OB]

First it is a 4R100 trans and the engeneer at Banks told me it was every bit as good as a Alison! They informed me that it shifted better and if one replaced the torque converter and put on the trans comand on it, that it would last the life of the truck. I did both and I added a temp gague. Under load in overdrive it just reaches 200 degrees. I live in California and will pull the hills going up to Mt. Shasta in overdrive, no problem, I must say that I have put a B&M fined pan on the tranny - and that did drop the temp. The last GM truck I owned was about 1960, and it was a 1947 chevy. I still own a 1970 Toyota Hilux, which is almost totaly restored. It is a one ton truck and the last of the eyebrow turnlights pickup. I am going to put it up for sale real soon. By the way - my truck is a 4x4 daully.

[jwiger]

Originally Posted by Randy Navarro

Is it better to take the tranny out of overdrive when pulling or o.k to leave it on.

Randy if your engine is loaded to the point that you can't accelerate with out more the 80% throttle then you need to kick it out of over drive. You really just need to have a feel for it. if you are in overdrive and have trottle left with out the truck down shifting then OD is fine for that situation.

[JayCarotenuti]

What the man said about the heat is most important. I move trailers for a living. I was backing a trailer uphill into a guys driveway. The trans overheated and started pouring out tranny fluid like water from a spiggot. It hit the exhaust and started a fire! Lucky I had a fire extinguisher!
I recommend a gauge to give you some idea of the temperature. Overdrive works automatic most of the time. But like the man said if it hunts, turn it off, if you want some resistance downhill turn it off. Otherwise I leave it alone and let the computer deal with it. I have had my share of tranny problems. Ford rebuilt the tranny and replaced the torque converter (twice) and it still dosen't lock and unlock correctly I would like to know about how that works, any suggestions would be nice, thanks

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Last edited by JayCarotenuti : 11-14-2005 at 11:38 AM.

[Mike OB]

Hi Jay: I was told that the Ford transmission is as good as the Allison if you upgrade the torque converter and add the trans command to raise the oil pressure to stop it from slipping. The trans is computer controled if you truck is late enough? you didn't say what year it was. The converter locks up to improve you fuel mileage, the overdrive is shifted into when the throttle valve pressure drops below governor pressure, the tps needs to show that your not trying to gain speed and the map sensor needs to show a low amount of load. If you can find someone with a scanner that will read your pcm you can watch all the readings to see what is missing. If your truck is late enough it will set a pending code and tell you what is out of range. (OK) - tps = throttle posision sensor - map = manifold absolute pressure (LOAD). It sounds like you have a problem that no one is chatching, let me know what city your in and I will try to find someone with the tranning to find your problem. You are going through too many torque converters. I just reread what I wrote and need to tell you that if the stop light switch is going bad and makes contact it will unlock the converter. Everything I have told you can be seen on a scanner, even the stop light switch. Good luck Mike