Q: Slow transmission fluid leak which the mechanic I went to says was caused by a faulty seal even though it was replaced last week.

asked by on

Last week I had a major transmission leak. Found out the bracket holding the dipstick tube in place broke and the seal which held it in was not functional. I replaced it. I found out 4 days later that another tube from the transmission pan was bent and I brought it to the shop and had it replaced by a mechanic. After sitting in my garage for 6 hours, I noticed transmission fluid on the floor under my vehicle. It started fine and showed enough fluid when I checked. The fluid was very small but prevalent. I took it back to the same mechanic who told me it the seal was bad and that was where the leak was from. My question is - why did it take 5 days for this particular leak to emerge? Does it really take 5 days of driving to build up that much pressure for a leak to emerge?

My car has 120000 miles.
My car has an automatic transmission.

Hi there. The problem with trying to diagnose this transmission fluid leak issue you have with the Hummer is that it’s quite possible that the leak could be caused by multiple issues. Certainly a loose transmission fluid tube or damaged o-ring can cause a significant leak. However, an external or internal seal leak can take time to build up pressure to leak as well. It’s also possible that the leak of fluid from the tube reduced the pressure inside the case. When that leak was fixed, it most likely increased the pressure inside the hydraulic lines which exposed existing issues with the seals. These are all SPECULATIONS - and POSSIBLE reasons, but it would require a detailed inspection to determine exactly why this has occurred.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Slow transmission fluid leak which the mechanic I went to says was caused by a faulty seal even though it was replaced last week.

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Intermittent issue where after a stop car is stuck in first, speedometer at zero. Had output speed sensor changed, no change.

Hello there, a few possible faults could cause the vehicle to become stuck in first. The most common would be low fluid level, shift solenoid, transmission range sensor, or a transmission mechanical fault. I'd suggest getting this looked at by...

Q: If the temp gauge don't go beyond the halfway point do I have a bad radiator? No coolant on grounds noted.

Hey there, thanks for writing in about your Toyota Sienna. You could have a leaking radiator without knowing it. I was taught that there are classes of leaks; class 1 is a leak that just leaves a wet spot on...

Q: Q: Engine sludge?

If you have excessive sludge in the engine, then the oil that you pour into the engine may not be able to drain down into the oil pan. You should change the oil and filter using 6 quarts of 0w30...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.