D6N transmission ?

I have a 2004 D6N and the excessive transmision temperature light comes on frequently and the machine shifts hard when going from forward to reverse or reverse to forward when the light is on. The trans temp gauge reads fine and I have even shot the trans with a temp gauge and it is only 140 degree f. when the light is on. It seems to come on usually when you are sitting there idling. Would it be a bad temp sensor? Also I am having an issue with my heater/air conditioning switch, the blower motors will quit working and the only way I can get them to start again is by using a wire and jump power from another source and they will start again and the switch works on any position for awhile. I have put a new switch in and no luck. Thanks for any help.

Did you check the transmission screens and filters?

Also, check for seepage from the breather which would be an indication of torque converter flooding.

You really need to check out your transmission and see if something is coming apart. With a Cat power shift the difference between a $8,000 repair and a $20,000 repair can be running it just a few more hours.

On a related note I talked to a good friend of mine who is in the wholesale parts business. I trust him and have known him for years. He always shots it straight and he said that American Independent does some of the best quality reman Cat power train work in the country. He was at there shop awhile back and he told me he was very impressed. He has traveled the world dealing with heavy equipment parts so his is a very valuable opinion.
I have never done any business with them or spoken to them I only mentioned them to him after seeing the posts on here and he commented this to me.
I will try them in the future .

Thanks for your kind words Cat Wrench! We will do our best to live up to the compliment! I'd be interested to know which friend of yours told you that- I think we owe him a thank you as well. Maybe you could PM me?

The only thing I would say about the prices you mentioned is that you're overpaying if you've ever paid $20,000 for just a dozer transmission rebuild. In all our years we've never charged a customer that. The most expensive D6 trans we've ever done was under $15,000 and our average rebuild cost is closer to $11,000. It's only when the contamination from the transmission spreads into the pump, torque, and diff-steers that it will run into the $20's and beyond.

What you said about a few hours is very true. Once something goes, it doesn't take long for it to take everything else out with it. If you haven't already, you might enjoy some examples of this in our Wall of Shame thread: https://www.heavyequipmentforums.com/...ad.php?t=17710

Keep us posted gravelpete!

:usa

You need to check fault codes before running the machine anymore. The N series pretty much fixed all the electronic gremlins but there are things that can cause what you are describing that are totally electronic in nature.

On your monitor somewhere you will see a rocker switch or button that has a check mark. Push and hold that switch for a few seconds and let go. The monitor display should shift to another mode. As I recall it goes from hours to mileage or RPM, to the next and then to fault codes. An active fault will have ServCode somewhere in the display. All the others are logged codes.

Post your codes and someone here should be able tell you what you have.

Good Luck!

I'm with John C. on this one. If the warning light is on and the gauge is reading normal, it sounds electronic to me. The hard shifting is probably the computer trying to protect the transmission clutches from slip damage. Your a/c problem sounds like an open power supply to the switch, maybe the fuse holder?

The only thing I could get from the dispaly after the hours and milage was 113, 623.02, 113, 668.12 End. In that sequence, does this make any sense? Thanks again for the info.

Those are transmission codes and I'll ask one of my sources tomorrow and try to post an answer tomorrow evening.

The 113 part of the code shows that the codes have something to do with the electronic control system for the transmission. The 623 code indicates the direction switch and 02 means the switch is erratic. The second code 668 is for the transmission shift lever and my contact says the 12 code shows the component, probably another switch, is bad. You didn't mention whether or not these were active. A lot of times these are just transient, or only happen once and then just long enough to log the code. It does kind of sound like this could be your hard shifting problem.

What I usually suggest is that a call to the dealer is in order in that it sounds like electrical components might be bughouse. You let them know the code numbers and tell them they should bring the parts with them when they come out. Don't allow them to make more than one service call by coming out, plugging in and then having to go back to get the parts they should have brought with them.

You might try replacing the components yourself but without hooking up the computer to the system you won't know if it is actually the component or just a bad wire which usually seems to be the case. A lot of times there also might need to be some reprogramming involved with new components.

After reading the last few posts, I have a question. Are you sure the light coming on is the transmission temperature light, or is it the transmission electronic malfunction light? Both code descriptions John posted were switch related, and could cause the symptoms of hard shifts, but not high temperature.

Maybe it is not the trans temp light? I will have to double check tommorow, I really appreciate the help.

I have a D6N 2003 which jumps out of reverse,forward gears are fine, would appreciate any advice??

Please elaborate. Does the transmission control lever move back to the neutral position when it jumps out of gear or does the transmission simply go to neutral and the lever stays where it is - I assume 1st speed reverse position..?

Have you tried it in all 3 reverse gears and does it do the same in all of them..?

If it only has the problem in reverse it can only be a failed clutch or reverse solenoid problem.

I would suggest checking screens for evidence of clutch material and if so, you may as well just pull it.

If you post a picture of the screens on here we can probably help analyze it.

Sorry, I was thinking of a manual control tractor not electronic. A good start here would be a Serial Number ......