Help, Cold weather Overdrive Shift?

[Cyprs]

Got a 92 Dodge Cummins Diesel, love the truck except one thing, getting this auto tranny to shift into Overdrive on cold days, at -20C with engine at full operating temp and after 15 minutes highway driving this thing will not shift to OD. The shifter options are 1st, 2nd, Drive, no OD on shifter, I do have an O.D. off/on button. I have to increased speed, let off gas and re-accelerate to get O.D..

I changed dropped pan and replaced tranny fluid and filter recently, set bands etc.

I am considering a syn tranny fluid blended in, can one blend syn tranny fluid with regular, will that help?

Do I need a thermostat on my tranny?

Should I increase my speed in 3rd gear prior to trying to engage my O.D., I dont like reving escessive expecially when oil may still be cold but may have to. These 5.9 diesels have lots torque and run cool, I am fearfull of blowing out the tranny especially cold even after 15 minutes operating. It will shift into OD at 60 KPH or 40 MPH summer warm, I dont like to go over 80 KPH or 50 MPH in 3rd gear in real cold drive conditions until I know that tranny is fully warmed, I know constant attempts to engage this overdrive cold (even though engine is fully warmed) is not good either, I dont know what to do to avoid damage?

Any tricks or tips on this?

thanks,
Cyprs

 

[tmorris1]

A friend of mine had this happen on his Dodge 1/2 ton when it was about -15. We were coming home from a fishing trip and it finally shifted into OD after about 50 miles. I've heard of other Dodges doing this too. Not sure why it happens though.

 

[medic]

I'm going to take a shot in the dark here.

The tranny is programmed not to let the truck shift into OD or lock up the TC until the fluid hits a predetermined temp. This is the only thing I can think of other than potential tranny failure.

I would suggest finding a forum about dodge pick-ups or diesels pick-ups and do some searching there.

 

[1 FMF]

I think medic is correct. I have a '89 F250, 7.3L with an E40D auto. It does the same thing, and I have 4k into a complete tranny overhaul when I bought the truck. So I know its operating properly. I've also confirmed this operation as normal over at dieselstop.com
There is a temp sensor on the tranny, talking about mine here, which will prevent it from shifting into 4th until the fluid hits a predetermined temp. It helps the tranny warm up faster. What that temp is I don't remember. And I believe it also alters the shift firmness and TC lockup as well, and this for a 1989. I'm sure on yours, being a few years later and with the increase in computers and sensors controlling more of everything on the vehicle, is the same case for you.

 

[97tbird]

Medic is right..

This can be very clearly seen with my 97 T-bird. when it's very cold, the 3-4 shift doesn't take place the 1st time i drive (4th gear is O/D); the car remains in the 3rd. I can see this from the rpm's. after about 20 min. when the ATF has warmed up, the computer lets the 3-4 shift take place. This happens every time when it's cold. I think this protects the tranny/TC etc.

When it's cold, I sometimes have turned O/D off to MAKE this happen even: I really believe it protects the tranny.

 

[Gary Allan]

This is an event that should surely be covered in the owners manual. It is for my jeep. The lockup will not occur until the trans reaches xxx °F (180 I believe).

It would be a real oversight to not have this covered in the owners manual. Why would you want potentially thousands of units scheduling warranty checks for a normal condition. The service writer taking your call isn't likely to bother polling you on when it happens ..he's going to say "bring it in" ..you bring it in ..someone throws the scanner on it anyway, you hear 'it's normal" ..don't believe them..and on we go....

 

[Cyprs]

Thanks, no the manual doesn't mention anything about this, oversighted I guess. At say -5C days the tranny will kick into overdrive after few miles, colder it is the harder to get OD, must be a protective sensor on heat operation of tranny, make sense, guess I have to be patient and run in 3rd at moderate speed cold till tranny warms. I have heard other Dodge drivers have problems with this, even my neighbor with a 99 Dodge Cummins. Thanks all.

When my engine is at full operating temp, and I cant get into OD, what is safe speed in 3rd gear I can travel with 273 rear end gearing to avoid engine or tranny damage, please specify KmsperHour or Mph? I dont have a tach.

Thanks,
Cyprs

 

[Greaser]

I'm using Mobil 1 ATF in my 99 XJ's AW-4 tranny and never had any shifting ,or any other problems for that matter,in almost 160,000 km.My 01 TJ on the other hand which is the 5 speed standard ,using the OEM fluid, is sticky when cold and on one occasion where it was sitting in -5 degree weather all day would not shift into overdrive untill it was warmed up for almost 10 minutes at highway speeds.Shifts great once it's warmed up though...thats why I like warming up my vehicles a bit before I take off on cold days.

 

[medic]

quote:

---

Originally posted by Cyprs:
When my engine is at full operating temp, and I cant get into OD, what is safe speed in 3rd gear I can travel with 273 rear end gearing to avoid engine or tranny damage, please specify KmsperHour or Mph? I dont have a tach.

Thanks,
Cyprs

---

I would say as long as your engine is warm, the speed shouldn't matter. Your engine has a governed maximum rpm to keep it from over-reving and twisting the crank.

My only concern would be the higher rpm's of the engine before it has had a chance to warm up.

[ January 03, 2005, 02:36 PM: Message edited by: medic ]

 

[Cyprs]

Greaser, I take it the Mobil ATF is synthetic? does the syn ATF help cold flow for shifting cold?

Medic, I ensure the engine is fully warm before putting any load on it , my main concern is putting too much torque on a cold tranny with excessive speed in 3rd gear with this diesel. I am told these diesels can blow a tranny if one is not careful. I am going to keep speed at 40-50 mph after engine warms completely with OD button off till tranny warms enough. Guess I dont have much choice if tranny wont shift to OD until warm. I do idle the diesel in neutral to try warming tranny too. I cant imagine continuous unsuccessful attempts to engage OD on a cold tranny being good for drive train.

I just learned my uncle had a problem with cold overdrive shifting with an early 2000 model gas Dodge truck . Apparently Dodge put in a different heat sensor on tranny and the tranny shifts into OD cold great now, I will call Dodge one day and see if they have a solution. If so I will post it.


thanks guys,
Cyprs

 

[Cyprs]

Hey guys,

I am considering a hot patch for my oil pan, if Dodge does not have a sensor solution then what about a hot patch for tranny fluid pan too, what would be a suitable wattage of patch, there is 11 quarts ATF, I dont know the pan capacity?

thanks again,
Cyprs

 

[andyd]

absolutely no experience with this problem. But a thought came to me whilst reading this thread. For an experiment, cover the radiator to block the airflow. This should warm the engine and trans more rapidly. Just keep an eye on the temp gauge.

 

[02supercrew]

Hate to break the news here, but it will not matter what super duper ATF you put in, the tranny will still not shift into OD any sooner, untill the ATF fluid reaches a certain temp.

This "effect" is also magnified by the use of an external tranny cooler, as it causes the ATF to take even longer to get up to temp.

This is also the same reason that ATF lines are often routed through the Radiator as the radiator often warms up much faster.

Just because the motor may be warmed up, doesn't mean the radiator has warm fluid in it, and is transfering heat to the tranny fluid.

I wouldn't lose any sleep over it as your tranny is doing what it is designed to do, but if you really want to help your motor and tranny warm up faster, install a cold front ( a piece of cardboard would work just as good). IMO this is a must on all diesel rigs.

[ January 07, 2005, 01:47 PM: Message edited by: 02supercrew ]

 

[Cyprs]

Thanks guys, got a good heavy duty thick winter front, I keep the flaps (air vents) closed solid when cold. I will have to be more patient and hit the OD button to off till tranny warms up. thanks

Cyprs

 

[02supercrew]

If you have a HD auxillary tranny cooler, you could cover that up when you are not towing if the cold front doesn't do the trick (but it should work).

Not to mention it will be a lot warmer in the cab!