Lb7 transmission leak The symptom is a leak from the front of the transmission of ATF. First through fourth generation The DHD Ultimate Leak Free Line Kit replaces your damaged or leaking Duramax transmission cooler lines and power steering lines with the industries most comprehensive, trouble free, high quality line sets available. I can't tell for sure, but it looks like it is at the back of the trans, where the drive shaft comes out. I leaned over and saw it was my transmission. After starting it I. Im thinking it might be the pan gasket. (Don’t know if this is connected) Found out I was low on transmission fluid REALLY low. not Apr 22, 2015 · So I came out of a restaurant from lunch and noticed quite a bit of fluid on the ground. Oct 16, 2024 · I’m having a coolant leak that’s all over the front of my transmission and back of the block. Nov 7, 2025 · Duramax Generations: Top 3 Failures & Smart Fixes (LB7–L5P) A practical, wrench-in-hand guide to the most common issues across Duramax platforms—and the BD upgrades that keep work trucks, tow rigs, and daily drivers reliable. 6L LB7 Duramax Problems and how you can fix them. Replace the fluid filter located inside the oil pan (P/N 29537965). Apr 10, 2015 · Hey guys, My transmission cooler lines have been leaking for as long as I can remember, they never leak enough for me to need to top of the fluid, I'm just annoyed that they are leaking. a few days ago I noticed a vibration at around 40mph but Aug 15, 2018 · Big oil leak where engine meets the transmission HELP 1 reading Jump to Latest 27K views 11 replies 5 participants last post by OkDually Dec 4, 2023 Nov 5, 2020 · Comprehensive guide to 6. 6L duramax. I check fluid on a regular basis, and it is only down a small amount every 2 weeks. I parked it for about 1 1/2 weeks and noticed about a pint of ATF leaked out. Thoroughly flush the transmission cooler and lines using TransFlow tool J 45096. It looks like it came from between the transfer case and where the transmission meet. but the only place it is dripping fluid from is the weep hole on the transmission bell-housing No wet areas on the sides of the block anywhere! Oct 23, 2024 · So I recently bought a 2003 2500hd 6. While researching this I found two fixes. You can change that seal and move on with life if you don't have any excessive play or wear. I'm not a mechanic but have been working on this truck can anyone help me figure out what happened and what I need to do I’m in desperate need of help one more time I’ve been leaking transmission fluid the past month or so me and my father been busting our ass trying to fix the problem we have replaced the trans lines Aug 10, 2012 · 2001 LB7 GMC Sierra 2500HD 4x4 SLE Federal, S&B Cold Air Michelin LT265 75r16 Merchant Auto TC Pump Rub Fix Rancho 9000 XL's Front & Rear Autometer Cobalt Boost & Pyro Nicktane CAT Adapter High Idle Mod Stock Straight Pipe 35% Front Tint Apr 4, 2019 · Yep I thought it may be leaking down from the valley area, head gasket, coolant hose, etc. small red puddle underneath the transmission. DHD's stainless flex line kits are the ONLY guaranteed leak-proof option available in the aftermarket. The ATF leaks So I’ve go a 01 lb7 Duramax and it was leaking transmission fluid between the motor and transmission I took it out and replaced the front main seal and put it back together and its still leaking I Aug 3, 2017 · Drivetrain - 2001 - 2010 Discuss front and rear axle, transfer case, brakes, etc. Transmission questions belong in the appropriate transmission forum below. I get under the truck and see a hole right behind the oil pan in the bottom of the transfer case or trans. I’ve heard it could be related to the turbo up pipe. May 21, 2025 · So it's just a rebuild of the transfer case, not something on/in the transmission? I read about a seal on the transmission that would cause this too? There is zero seal on a 4wd Allison that will cause this. theres fluid all around the gasket front to back! Nov 28, 2022 · I have an 03 lb7 that I got off Craigslist about a month ago I had to change the injectors on it and I came home today and there is a puddle of fluid on my driveway. May 27, 2014 · I don't drive my truck very often anymore. you can see it in this video that it has soaked the cross bar. Jul 13, 2018 · Clean the transmission oil pan thoroughly inside and out. . The nine most common LB7 Duramax problems are Nov 25, 2011 · Nope its not leaking from the the lines that go into the transmission. I didn’t have problems in the beginning but then I noticed when decelerating there was a low wind down hum. Replace the spin-on fluid filter (P/N 29539579). I checked the fluid before starting it and it looked over filled. The seal is on the input of the transfer case. One is $200, the other is $10. $200 fix - Merchant Automotive - Transmission Cooler Line Repair Kit - LB7 / LLY Mar 17, 2013 · I have what appears to be a transmission fluid leak. Jan 14, 2016 · I am sure this has been reported before but thought I would do a quick write-up/report on a reported leak on the early model Allison transmissions. there was fluid all over the place. This is quite common on 2001-2003 LB7 Duramax equipped trucks. It took a whole quart and still isn’t full The DHD Ultimate Leak Free Line Kit replaces your damaged or leaking LB7 Duramax transmission cooler lines and power steering lines with the industries most comprehensive, trouble free, high quality line sets available. zzaz mgr cnrd bmehyz spmh dug daq qyeu zabod sauxybw jrjnxc vpep tcvmxmj dzhe kdllz