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Any help with these problems?

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Well, I am at the point of pulling my hair out, and I need to keep all the hair I have. lol

I have a couple problems with the truck that I will be happy to listen to anyones input on.


First problem;

Is a loud noise I have that comes and goes on the drivers side?? I have tried a few fixes that I have listed below but none of them were it. It is a weird noise to descibe, I thought it was an ignition noise at first but I think I got that ruled out. I was talking with Butch (AWDGM) today (he took it for a run down the 1/4 mile last night to listen to the noise. Anyway talking with him on the phone today after we ruled out a bad coil he was thinking that it might be a lifter sticking at times causing a backfire through the exhaust. I am open to any ideas, so let them fly..

I can't bring it to a dealer to have it checked out with out getting my warrenty voided but Butch said I should try to get it Data-logged somewhere to see if we could find the problem. I am going to give that a shot.


Second problem;

Is my tranny is running way to hot for my taste, it use to run in the 170ish to 180ish area on the transmission temp gauge. It now run between 210 to 225.

What are my options on this and can I get it to run cool enough so I won't be killing it? I have a Sale pending on my Lightning truck and the new Aluminum trailer I just bought. With my 2 year old son I don't have the time to go to very many away races like I use to be able to do. It is a great and fast truck that I am going to miss but to have it just sit in my yard on the trailer and not have the time to use it is a waste of a fun truck. Anyway I was scheduled to deliver it today 400 miles away, a trip I could not make with the Denali having a 225 degree trany temp with out even pulling the 7000 lbs.

I have seen people talk about the B&M trany coolers with the sensor and fan, what kit are you guys using?? The BMM-70297 or the BMM-70298, and is there anything better than that? I need to drop this trany temp right away.

Thanks for any help and I added the next part form a different thread that is already open in case you haven't read it.


P0420--Catalyst Efficiency Below Threshold (Bank 1)


P0894--Transmission Comp. Slipping


And the new one I got today was;


P0741--Torque Converter CKT Performance or stuck off


I now have gutted converters, I did that thinking that the drivers side honeycomb might be loose making the noise I was hearing. I was wrong still have the noise.


Thought it might have been my Spark plugs, changed them three times. I was wrong still have the noise.


Thought it might have been my wires, made some custom wires, noise still there, bought a set of the Taylor wires and put them on. I was wrong still have the noise.


Last, thought it might have been a bad coil on the drivers side. Changed all the drivers side coils to the passenger side and the passenger side coils to the drivers side. I was wrong still have the noise.


Besides seeing that I am wrong a lot, I haven't figured anything else out. lol


That problem wasn't enough so I had a Yank TT2600 stall converter put in and did the shift kit. Now my transmission temp runs between 215 to 225 on the highway and that is not even towing anything.

And the worse part that bites me right in the ass is that my 60' times didn't get any better and I lost 1 tenth and 4mph in the 1/4 mile..

And now I have a truck that I am starting to dislike..



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did the trans run that hot before the shift kit with only the converter? any codes before the shift kit and did they only come on when you went to the track? does your truck have headers on it?

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On the trans temps, add some fluid. With the 2600, my trucks trans temps didn't change. BUT, at first, I had too little fluid and it ran hot, stalled too high, and really didn't pull like it should have. I was about 3 quarts low. It would have been slower had I run it.


Not sure about your noise. Describe the noise itself more.

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I don't know if I can offer you any advice but this was the same thing I saw when I did headers/Free flow cats/cam/Yank 3000/Tune......Trans temp came up and I lost performance, big time...


I put in a larger heat exchanger, High Capacity Intercooler Reservoir and some fine tuning, and my Trans and IAT temps did come down......


Just reticently I have noticed a grinding noise just under my feet, it happens after a few hard romps....The truck goes in to my buddy at the Chevy dealer Monday..


Let us know what you find out and I'll do the same.....


Good luck,


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It only heats up on the highway, driving around town it seems to run normal temps. I do have headers, here is my performance mod list to date that I can think of;


Westers 93 octane tune

Volant cold air intake, with ram air

Screen removed from mass air

Ported throttle body

Dynatech longtube headers (Supermaxx header, cats, and mid pipe package)

high flow cats--now gutted

Corsa cat back

Flex-lite 282 twin electric fans

180 degree thermostat

ASP underdrive crank pulley

Yank TT2600 stall converter

Superior shift kit

Billet servos

NX wet kit, with heater and purge- not yet tested in the 1/4 mile


I had the converter installed on Monday, never had it on the high way until after the shift kit and it was on the way to the track. The SES light came on and that is when I first saw the tranmission temp go over 180's.

Evan had mentioned my e-fans and that that might be part of my cooling problem.

So I just got back from about a 60 mile highway test. I jumped my fans to stay on high, never went over 185* for about 30 miles, I pulled over and put the fans back to normal and with in 5 miles I was at 215* I pulled back over jumped the fans back to high then got off the highway to get the temp back down some. I got it back down to about 190* and jumped back on the highway for another 20 miles or so and it never went back up.

I guess it is time for the biggest and baddest Tranmission cooler and fan set up I can get that will fit in my lower grille opening. I want to move it lower and away from the radiator, that way the heat from the transmission cooler isn't getting sucked through my radiator and heating up my engine.

I erassed the codes I had this morning and on the 60 mile test run tonight no SES light came on.

One thing I do notice with the shift kit is after a highway run of some decent miles, when you jump into the city the trany shifts nice and hard. Quite a bit more than when you first leave the house..

Any ideas on any of it, best transmission cooler and fan set up with a temp sensor for me??




on the fluid, it was a little high, when I noticed the temps going up and the SES light came on on the way to the track I jumped off the turnpike and went to an AutoZone. They read the codes for me while I bought 4 feet of rubber fuel line and sucked out almost a quart of the Mobil 1. It is now right in the middle of the two marks on the stick. It was about 3/4" to 1" higher than the second dot before I sucked some out.

On the noise it is coming from the drivers side rear of the engine, you can feel it in the peddle when it does it. It is very loud, kind of like a poping, rattling, gurgeling noise. Sorry so vauge, but it is hard to put an exact sound on it.

The higher you are reving the quicker the noise is, after it does it it seems to do it on and off at all different rpms for a minute or so. It could be a backfire throught the drivers header I supose, not sure.



You might have the same noise as me, same place anyway. I hope we both can get this taking care of.



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Here's a guess on the noise:


Take a look at your header pipe hanger were the 2 header pipes route together towards a common hanger. Also look and see if your exhaust pipes (after cats) are touching one another. Another place to look is the heat shield on the drivers side headers, I had to have mine tack welded to the headers cuz it would rattle on the header tubes.


The noise sounds similar to what I had when I had the ASM headers installed. They were rubbing together when they heated up and grew…

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When i took Bill's truck down the track, the noise started around 4000 rpm in 2nd gear and stayed till I shut down. Pretty loud and can be felt under the feet on the floorboards. Another race, Bill was in his truck and I was in mine, he had me by 3/4 length when I head his noise from my truck, and I have loud exhaust! Definatly a popping/raspy noise out the exhaust, but LOUD. It's got to be either a bad missfire, which we've almost ruled out, or an exhaust valve not closing/sticking due to a bad lifter, broken spring or bent valve. I've heard stuck exhaust valves before, when the cylinder fires, the combustion takes place partially in the header tube. Good thing it's not an intake!


That's my best guess right now, though I want to see what a realtime data log will show, it still could be ignition related! We're at a loss!


Butch 02 Sierra Denali

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Unfortunatly the problem is intermittant, that's the wierdest thing. It runs with no noise 99% of the time. Still worth a look under the covers though. That'l be next, after the data loging to rule out ignition.


Butch 02 Sierra Denali

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You can feel it in your petal... Most often when I can hear and feel a sound like that in my truck, its the exhaust pipes coming in contact with something. Once I had this problem and checked everywhere and there was clearance. Turns out that there was a small bolt holding the heat shield that extended down and was touching the top of the cat. It appeared to have plenty of clearance though.


Also, check the trans coolant feed lines to see if they are laying up against your ASM headers. Mine were and needed to be bent some.


I ran a B&M trans cooler on my old truck. I'm just about to swap it in to my SS. I've noticed trans temps getting warmer now that I'm running the A/C most of the time. It came with all the hose and fittings to install. I think it was this one: http://store.summitracing.com/partdetail.a...BMM-70268&N=120

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