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The Gagsu LPD47391 40k Transmission Oil Cooler is a heavy-duty, aluminum cooler designed for vehicles up to 40,000 lbs GVW. Featuring advanced low-pressure drop technology, it maximizes cooling efficiency while minimizing energy loss. The kit includes all necessary mounting hardware for straightforward installation and is engineered to maintain optimal transmission temperatures, enhancing durability and fuel efficiency. Supported by a lifetime warranty and dedicated after-sales service, it’s the ultimate upgrade for professional-grade towing and heavy-duty applications.




| ASIN | B08WS5Y9Z8 |
| Assembly Required | Yes |
| Brand | Gagsu |
| Colour | Silver |
| Country of Origin | USA |
| Customer Reviews | 4.2 4.2 out of 5 stars (524) |
| Date First Available | 14 April 2021 |
| Exterior | Metal |
| Item Form | Oil |
| Item Weight | 2 kg 840 g |
| Item model number | LPD47391 |
| Manufacturer | Gagsu |
| Manufacturer Part Number | LPD47391 |
| Material | Aluminium |
| Model | LPD47391 |
| Net Quantity | 1.0 Count |
| Number of Items | 1 |
| Package Dimensions | 64.13 x 26.37 x 6.98 cm; 2.83 kg |
| Package Information | Tube |
| Recommended Uses For Product | Automotive |
| SAE J300 Viscosity Grade | 10W-30 |
| Specific Uses For Product | Heavy-duty applications, racing, towing |
| UPC | 726312342859 |
L**7
I replaced the small factory tow package cooler since my temps were near 200 degrees and would go over 200 degrees pulling my boat. I flipped the bottom bracket around and used a grinder to notch it so I could mount the trans cooler to it (had to slide the cooler to the passenger side a bit to clear the mount for the PS cooler). I used a brake line cutter to cut the factory lines off horizontal, and then used a brake flare tool to slightly flare them. I doubled up on the clamps where the hose connected to the factory lines. On the cooler, I used pipe thread tape around the fittings to ensure no leaks. Pros: seems to be working good. Put about 50 miles on the truck last night on the highway going 80 MPH with the AC running. Temps never got above the halfway mark from 100 to 200 (so I'm guessing that's 150 or 160 degrees). Install took me about 2 hours in my driveway. I used everything included in the kit (had to cut the hose to fit). Cons: fins are really easy to bend. I had to use a small flat blade screwdriver to straighten some of them out after I was done mounting the cooler. Also, the included clamps are cheap. I've got a tiny drip from the return hose where it clamps to the cooler fitting. I'm going to replace that clamp with a clamp from the auto parts store tonight. My advice would be just get 2 packs of small hose clamps from your local auto parts store and use those instead of the included ones. Also that included screws will strip easily at the phillips head. I used a 10mm socket to tighten them. I snapped one off but I guess I didn't drill a large enough pilot hole for it to mount to the bracket on my 2000 Chevy Silverado Z71. I also flushed the transmission while I had the stock cooler off. I used some clear 3/8" hose and ran it into a bucket. I started the truck and while the dark old fluid was coming out I was pouring in new fluid until it was coming out red. Then I installed the cooler, added more fluid, started the truck, and kept adding fluid until it was at the proper level. I think I flushed about 3 gallons (12 quarts) through it to get the dark fluid out. I ended up buying 5 gallons of fluid total (in gallon jugs from Walmart) and I have about a half jug left after the trans was full. If you don't need to flush yours out you won't need as much fluid.
B**R
Got this after seeing the test video on the Half Fixed Garage YouTube channel. The cooler was tested by itself with integrated radiator cooler bypassed. Temperature sensors before AND after the cooler. Fluid cooling of 30-40 degrees while driving and almost 50-60 degrees of cooling at stop lights. Tested in a duramax with Allison trans.
A**R
Bought a camper which we started towing with my 2004 Nissan Armada. However, when we started towing, we noticed the transmission getting hot. After researching, I realized that the factory transmission cooler is not big enough, especially for towing, so I looked into an exterior trans cooler. This one had excellent ratings, so I gave it a shot, and it has been amazing. I disconnected the stock transmission cooler, which is in the radiator and installed this external unit in its place. I am so happy I did. Our trans temp has not been elevated since we put this cooler in. It is well built and appears ready to last for the long haul. Could not be happier.
L**W
If I could rate this zero stars, I would, My shop recently rebuilt a transmission and installed this cooler onto the customers vehicle. Customer left with vehicle for one week and called to inform us that the vehicle stopped moving. Once the vehicle was delivered to our shop and we performed an inspection. We found that upon the inspection that this cooler had developed a pinhole, due to a failed casting, and the customer lost all of their fluid and burnt up the rebuilt unit. Upon teardown this unit will require $1700 in parts and $1500 in labor. I’ve reached out multiple times to this seller to see if they will help get this customer on the road by covering the parts and my shop covering the labor. They have declined. Why should the customer or the shop have to be stuck with this bill? You expect to have purchased a tested unit. But instead my shop will be paying to fix this hiccup. It’s not the customers fault. It’s my shops fault because we thought we had a good product by a good company and they have unfortunately disappointed us. We will not be doing business with this company again and to them that’s a relief because they get away with this and will continue to sell these poorly made coolers.
L**S
Works great, easy install. I ordered -6 a fittings and ptfe lines. I went from normal 175 cruising and 210/215 in stop and go traffic down to 170 in heavy stop and go traffic and drops immediately to 150s once you get moving again in about 80* Cali weather, car has a built LS engine with 4l80e. I did bypass the radiator completely.
Trustpilot
3 days ago
2 months ago