Hayden 679 Universal 11” Rapid-Cool Add-On Transmission Cooler to Enhance Cooling (not for direct replacement of the factory unit)

2000 chevy silverado btr red hot cam 3000 stall 4l60e trans temp was 210..now down to 185 cruising 194 beating it..also have a 7in fan and bypass the radiator as the cooler in the radiator can burst and destroy your trans instantly...plus the radiator cooler raise temps..in the winter just wait till trans temp comes up before beating on it also use vovaline maxlife trans fluid thiner and better then dex..

Works good. Haven't hooked up a computer to see what my temps average yet but I'm sure it's better than factory trailblazer coolers.I used mine to bypass the OEM since it broke. I mounted mine with some copper straps and self tappers from home depot. Don't bother with the wierd zip tie things. Hardest part was flaring the OEM hard lines and wrangling the cooler itself into place.

Installation was a breeze. I just used some aluminum bar stock I had laying around along with some various nuts and bolts. I did NOT cut the factory lines like others did on their GM trucks. I saw no need to use multiple compression fittings that would create more potential leak points. The ends of the factory steel lines already had nice barb for the hose to fit over. Just loop them around like a pretzel and call it good. This is not a high pressure system so it will be fine. It doesn’t need to look nice, it just needs to be functional.I am seeing temp drops of 25-30°. On a 90° day, the transmission will not see over 160°, which it would normally be 200°.

If you're looking at this cooler you are probably concerned that your transmission is getting too hot. This cooler will cool it down significantly. Here's my details.I have a 2003 Chevy Suburban 2500 with just over 100,000 miles that I recently purchased. I use it around town and tow a 4500# trailer. Recently I was towing in the Northwest hills of Connecticut and the truck's OEM transmission temp gauge showed 200 degrees, which is the highest I had seen. It usually runs around 140 when the temps are below 70 and progressively higher when the outside temperature is greater. The weather has been around 90 for a few week and I see temps of 180 or 185 without a trailer. I decide to add a cooler and seeing reviews it looked like the quality of Hayden was really good. I even called them and they were very helpful suggesting the 678. I opted of the 679 to get even more cooling.Installing posed some options. My truck came with a factory cooler about 1/3 the size or the 679 and mounted on a plastic brace that was then mounted on an aluminum cross member just behind the grille. In order to efficiently use the OEM cooler I needed a fit kit, which my local Pep Boys carries, so I went there rather than waiting for delivery and got a Hayden kit 390 as the instructions indicated. Good thing I didn't order it, because it turns out I needed a kit 393. When I went back to Pep Boy I decided the scrap the OEM cooler and buy another Hayden 679, which wouldn't need the fit kit, and mount them next to each other. The cooler I bought at Pep Boys was made in Australia and the cooler that came from Amazon was made in Korea, but the quality appeared similar to me. Fully installed, my coolant flows from the transmission to the radiator, then to a Hayden 769 and then another Hayden 679 and back to the Transmission.Yesterday it was 100 degrees and I took a long drive with no towing load but 6 passengers. Prior to the cooler I would expect to see 185 and the warmest the gauge showed was 150, but was running at 135 most of the time. I would say the two coolers reduced the temps by 40 degrees. Excellent results for an easy job.

Appears light weight but it does the job well. On my Chevy Avalanche 2500 with an 8.1L Vortex V8, during 35+ mph my trans temp reads 150 degrees. Below 35 when the temp reaches 160 degrees the 10" fan I put in front of it kicks on and drops the temp back to 150. The proof will be when pulling my 32' 6000lbs travel trailer later in the year. The old trans cooler is less than half the size and on hard hill pulls I would see up to 215 degrees. Ouch!The Hayden 679 "just" fits. I had to create my own brackets for mounting. The trans oil lines on the 2500 with an 8.1L engine come up through just left and right of center under the radiator. The Hayden connectors are almost perfectly in line with the trans lines. Simply cut the lines, remove the old trans cooler, flair the tubes, and use 3 to 4 inches of included hose to connect the lines. The nice part about this is it is impossible for the hose to come off. The hoses can't go down. There's a bend in both trans lines that won't allow this. The hoses can't go up, the cooler is in the way. If the cooler performs well pulling my travel trailer then I'll be really pleased.Adding some praise to this transmission oil cooler. I was looking forward to towing my travel trailer into Colorado this year. Unfortunately because of not just one but two idiots, my Avalanche was taken out of commission. What's this got to do with this cooler? The second accident was a front end collision where a driver tried to make an off ramp, hit the guard rail and bounced his car at a dead stop in front of my 8,000 Lbs Avalanche doing 45 on the off ramp. Bam! Major front end damage, and yet this oil cooler is still in one piece, bent, but no leaks at all. I'd almost use it again, but instead I just ordered a new one to replace this bent but still functional one. Tough little sucker.