I installed a set of iss pro gauges about a year ago exhaust and tranny temp. the exhaust has worked flawlessly ,but the tranny was sporatic at first then it just quit after about a month I checked all connections and wires nothing fishy or strange I figured the sending unit crapped out. I was just about to contact iss and purchase another sending unit until this weekend it started working. I was going up a huge hill major grade and probably 2-3miles long towing my loaded up fifth wheel camper. I was creeping up the hill about 20 mph in low gear wondering if would ever end. Then BING the tranny gauge jumps from 100 to 210 it worked until the tranny cooled down to 190 then it went limp any ideas?

I also experienced a whistling noise when the truck was under load between 2800 and 3000 rpm any ideas? thanks

oh yeah just ordered my chip from total diesel performance economy/heavy tow and extreme! how extreme is extreme

thanks Tom

 

I dont know if your truck might have this but the whistling could be a crack in the exhaust manifold. how high were your EGT's? do you have a boost gauge? did you notice a reduction in power? I think thats normally a problem with the 6-leakers, but it could be an engine i would think.
I dont know about the gauge thing.
I think i remember that the most a tuner can squeeze out of stock sticks is something in the neighborhood of 80-90 hp, even though they'll advertize 140 .
Watch this video. it's a 6.0. Is that the sound?
http://community.webshots.com/album/559085586TRiWWp
That's what a cracked manifold/ uppipe would sound like.
Edit: It usually involves their EGR system. i suppose it could be a crack though.
Can you describe the sound better?

 

that is much worse sounding than my whistle. I am gonna check under the hood for any signs of leakage. my noise sounded more like a sucking than a pushing. I do have a tymar style intake and oversized downpipe and exhaust.
the noise did not affect power it was just something I had not heard before.
my egt's were 900-1100 i don't have a boost gauge

thanks