jlrosine
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Re: Bypass radiator/tranny cooler combo?
It has electric fans so it's definitely not fan noise. This does sound like a bearing in the drivetrain to me. When I apply the brakes harder going down hill it gets louder/more whining/higher pitched. When I throw it in neutral it goes away.784Views0likes0CommentsRe: Bypass radiator/tranny cooler combo?
hey guys, I can tell there are quite a few tranny/gear heads in this thread so I'm going to post this here. I have another towing update and figured I'd get your thoughts on the results. I towed my camper again over the weekend but this time I went up highway 285 in Colorado. It's still steep but not nearly as long and drawn out as i-70 here. It was a bout a 2hr drive and ended up stopping around 10,000ft. Result: I experienced the front end whine again but it was quieter this time, and didn't last as long. After I got to less grade/more flats with hills, it generally goes away slowly. On the way home last night, I was heading from 10,000ft elevation down to about 5,000ft. I payed close attention to the temp gauge for the tranny and it never got above 180-190. The outside temp ranged from 45 degrees to a max of about 65 as I got down in elevation, however I did start to hear the same "whine" sound coming alive after I was using the gears to hold down a 5-7% grade (usually 2nd gear with minimal braking) Given that the transmission wasn't hot, or wasn't nearly as hot as previous runs, I'm now wondering if it's my transfer case/front diff making the noise and not necessarily the transmission? I generally start to notice the whining noise when I touch the brakes even lightly, the noise only comes from the front and it seems that it's due to the braking stopping the wheels....which are connected in the AWD to the diff/case...then the tranny. Temp wise it doesn't seem like it was nearly as hard on the transmission to use it to brake down the pass, but I'm sure it was equally as hard on the transfer case/diff as going up hill. Any thoughts or speculation?784Views0likes0CommentsRe: 2005 Yukon XL Denali tranny whine while towing/braking?
Hi guys, I have another towing update and figured I'd get your thoughts on the results. I towed the camper again but this time I went up highway 285 in Colorado. It's still steep but not nearly as long and drawn out as i-70 here. It was a bout a 2hr drive and ended up stopping around 10,000ft. Result: I experienced the whine again but it was quieter this time, and didn't last as long. After I got to less grade/more flats with hills, it generally goes away slowly. On the way home last night, I was heading from 10,000ft elevation down to about 5,000ft. I payed close attention to the temp gauge for the tranny and it never got above 180-190. The outside temp ranged from 45 degress to a max of about 65 as I got down in elevation, however I did start to hear the same "whine" sound coming alive after I was using the gears to hold down a 5-7% grade. Given that the transmission wasn't hot, or wasn't nearly as hot as previous runs, I'm now wondering if it's my transfer case making the noise and not necessarily the transmission? I generally start to notice the whining noise when I touch the brakes, the noise only comes from the front and it seems that it's due to the braking stopping the wheels....which are connected in the AWD to the case...then the tranny. Temp wise it doesn't seem like it was nearly as hard on the transmission to use it to brake down the pass, but I'm sure it was equally as hard on the transfer case/diff as going up hill. Any thoughts or speculation/recommendations?578Views0likes0CommentsRe: Bypass radiator/tranny cooler combo?
Interesting Larry. So what I assumed and what others assumed here was wrong, that it would heat the fluid up considerably. It's good to know that it isn't going to affect my cold weather driving much if at all. FWIW I towed my trailer again this weekend up to about 10,000 ft. , the Yukon did great but about an hour in I got more transmission whining again. My temps maxed at about 230-235 I think....or close to that, most of the time they were in the 200-225 range.359Views0likes0CommentsRe: Bypass radiator/tranny cooler combo?
I think you are assuming too much. http://www.topix.com/forum/autos/gmc/T7G5S6Q7Q5B2BSC0D/denali-transmission-cooler-failure-ruins-transmiss Examples of a car with 74k miles having the issue. Nissan did this on the Xterras for a few years too, then they fixed the problem by not routing it through the radiator. Nissans was a much wider spread issue, but it was a lot easier to bypass too with flex lines instead of stainless.144Views0likes0CommentsRe: Bypass radiator/tranny cooler combo?
I don't think it's more than I've thought about. if I did the bypass I'd probably hook it back up if I ever sold it to someone else. For my situation...I only use the Yukon for trips/towing, the rest of the time I drive a car or my van, so my purpose is very specific. I also have it garaged with insulation, always 45 degrees + here. My biggest beef with running the tranny fluid through the radiator is the damage it can cause if it cracks internally. Do a little googlin' and you'll find countless threads with this. It's like built in obsolescence IMO.119Views0likes0CommentsBypass radiator/tranny cooler combo?
Hi all. I have a 2005 Yukon XL Denali and wondered if anyone else has had success doing a radiator bypass for the tranny lines, and just using an Aux cooler on the front? Issue 1: From the factory, GM and other manufacturers run the transmission lines through the main radiator and it shares space with the antifreeze (separated internally). If anything internal cracks inside the radiator...bye bye transmission. This has happened to quite a few people and seems absurd to design it this way. Issue 2: The radiator/thermostat want to operate at 180 degrees. Why in the hell would we want to heat the tranny fluid to 180 then try to cool it again in a tiny little cooler on the way back to the tranny? It seems to me that the best solution would be to just bypass the big radiator, thus reducing the risk of blowing my transmission if the radiator leaks/cracks/mixes antifreeze in my tranny fluid. Then I would need to install a larger aux cooler on the front to make sure temps stay low. Is there a downside I'm missing to this? I know that some people think the reason it's designed this way is to actually heat the tranny fluid up on cold days, but given that it wrecks my towing and temps in the mountains, I think I'd rather just disconnect.9.7KViews0likes33CommentsRe: 2005 Yukon XL Denali tranny whine while towing/braking?
I should have noted this: The Yukon has been very well maintained at a local GMC Dealership. Every 30k miles up until about 120k the transmission fluid/transfer case/diffs were flushed, so it's definitely not a situation where it was neglected. The tranny fluid is bright red, looks brand new, and there's not even a hint of brown really. The stock transmission cooler is fairly large, not much smaller than the one sent in the link above however I'm sure the tru cool does a better job, it looks a little thicker anyway, I'd be surprised if a new slightly larger cooler makes a 30 degree swing on temps, but I could be wrong. There's only so much fluid running through the cooler at any given time and it takes a while to cycle it through. I know I said that the whine gets louder with temp, however it doesn't really go away when the temps are in completely normal operating range. 180 - 200 degrees for a transmission isn't crazy hot IMO, and especially not when towing. @APT - Yeah the main reason I was looking at the ecoboost, or an old Excursion was because of the turbos and the elevation I tow at. We plan to do a lot of Colorado camping because we live here and it's "easy"...easy until we have to go up passes and back down them with a trailer. For resale and longevity I'm not sure how the Ecoboost will hold up, I haven't seen a long enough track record to tell how durable they will be. I think the next best towing SUV would probably be the Toyota with the 5.7, I've owned a Tundra previously and I know that engine/transmission are up to the task, I just need to also haul 4 kids and a wife :).578Views0likes0Comments
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