Transmission problems... I think

[87Skier]

Originally Posted by pound41

Many years ago my I was driving my blazer and thought I had Tranny issues. I took it to my Dad who own a service station for 40 years. Even in the era of scan tools in the latter part of his life. He never used one. he drove it around and said Clutch fan. He was right. He told me most people have no idea how much the clutch fan effects transmission shifting etc. About a month a go I am driving my 2003 2500 HD with Allison 5sp auto. I start hearing a noise in the motor or so it seems. It is not running well. Then it goes to where the tranny is not shifting well, High rpms feels like it is slipping. I am praying I make it home and I am thinking what does it cost to rebuild the allison trans. About a mile from home it levels out and goes back to running well. I hear my Dad's voice in my head Its your clutch fan. I check it when I get home Fan is wobble. 50 bucks new clutch fan runs like a new truck. Fairly cheap as well. Just a thought
Good Luck

If that doesn't work out, I would be looking at the fuel system. There have been several posts on here about people with clogged fuel filters and kinked fuel lines that have literally driven years without their trucks going over 60 mph.

If you have an older quadrajet, check the filter in the carb. These seem to get overlooked.