Archived 2004 2500 auto trans problems

[SSwords]

Ok I have buddy that was not very bright and went to a local trans rebuild place to get his trans rebuilt. He got it back after a $2500 bill and it is still messing up he took it back and now they say that the fan clutch is making it shift funny I have never herd of this before the truck is not overheating and it is doing this under normal driving he did not make it 20 miles from the shop before he took it back. He does not have any gages so I can not get the trans temp but the light is not on in the dash and the check engine light is not on but it is doing a horrible double shift until it gets to about 50+mph like 4 up down shifts before it locks in the converter . I hate to do the throw parts at to fix a problem and that is what it sounds like they want him to do. I just got a call from him and he said that the first time he went to pick it up it did not have reverse to tell you the quaitly of work.

 

[Missouri Mule]

Tell him to try and get codes(if he has any). Can't see where a fan clutch would mess up the trans but being a 3rd gen there is the possiblity that if the clutch is on the ECM and/or PCM would know it. If the fan clutch is on or off all the time it could be keeping the trans form shifting correctly the trans temp sensor sends data to the ECM or PCM.

 

[Yo Hoot]

I'm having a similar problem with my 04. We think it's related to the computer and the temp. I have a temp gage that I just have not had time to install but will do soon because I can't keep driving mine when it acts like this.

See if you can find out more about this fan thing.

 

[HBarlow]

The information and advice offered above sounds right to me. It COULD be related to temp sensor and fan clutch.

Recommend that your friend take his truck to an autoparts store that will hook up a scanner and read the codes for him. If there are codes set that might help him toward understanding the problem.

Next alternative would be a trip to a dealer.

When questionable repairs are made it is sometimes very difficult to identify problems because you can't eliminate the recent work as a possible cause.

 

[Yo Hoot]

What temp sensor are you talking about HBarlow?

 

[HBarlow]

I'm not a mechanic, only speaking in generalities. I'm assuming that the ECM/PCM monitors engine coolant temp and if the computer thinks the engine is over a set temp it engages the fan clutch and could possibly be setting a limp mode that effects the transmission.

 

[Yo Hoot]

There is also a temp sensor in the trans that's located on the valve body.

 

[SSwords]

I don't know for sure but I thought that the fan was a temp activated not electric but I have not looked at my truck close enough.

 

[Yo Hoot]

The fan is run by the computer as far as I know.

Mike

 

[Missouri Mule]

I was talking about the trans temp but the coolant temp could be sending wrong data to the ECM/PCM. I'm not sure if shifting or convertor lockup is tempature controlled, tempature is used for shifting into overdrive on the 47re.





More info on the Trans temp sensor. This is for the 47re which should be similar in electronics to the 48re. From the 96 service manual.



Trans tempature reading are supplied to the transmission control module.

" The tempature readings are used to control engagement of the fourth gear overdrive clutch,the convertor clutch, and governor pressure. Normal resistsance value for the thermistor (trans temp sensor) at room tempature is apoximatelay 1000 ohms.

The PCM prevents engagement of the convertor clutch annd overdrive clutch, when fluid tempatures is bleow aprox 50 degrees F. "