Author Topic: Should I replace transmission drain pan & gasket myself?  (Read 596 times)

Fru-Gal

  • Handlebar Stache
  • *****
  • Posts: 1338
Should I replace transmission drain pan & gasket myself?
« on: June 08, 2024, 03:52:00 PM »
Joys of car ownership: I noticed oil spots on the driveway and found that a leak has sprung from the automatic transmission drain pan. It appears to be coming out of a weld that was poorly done by the dealer who sold me the car and put in a new (old) transmission, drilled it to drain it, then welded that hole shut.

My mechanic would either improve that weld (he says he does that all the time) and replace the gasket, but I question why not simply buy a new pan. He said because they’re rare, but I found many of them for cheap.

I used to do my own car repair, decades ago. Rebuilt engines, etc. Only blew up one. Replaced the oil pan on one car with an oil pan from the junkyard when the oil changers guys stripped the drain plug. Even changed my oil a few times (and properly recycled it).

Most recent successful repair was replacing plugs and wires on my old car after getting a misfire code. That went well and lasted till we got rid of car. This is the new car, a 2003 RAV4 with 95k miles. Dealer did not disclose this was a replacement transmission, my mechanic pointed it out.

Mechanic will do it for about $200.

I might also need a water pump, he’d do that for $300.

Should I do this transmission drain pan replacement or not get my hands dirty and let him do it along with the water pump? Seems like it will be messy, I may have to buy some new tools, and putting the gasket on correctly (getting it to stick) can be tricky. Plus my biggest concern is messing it up and then having to tow my car to the mechanic.

This is my new mechanic and a month ago he did a great job with a suspension repair that also was technically in the DIY realm.
« Last Edit: June 08, 2024, 03:58:20 PM by Fru-Gal »

Brystheguy

  • 5 O'Clock Shadow
  • *
  • Posts: 33
Re: Should I replace transmission drain pan & gasket myself?
« Reply #1 on: June 08, 2024, 10:26:47 PM »
I would have someone change the pan and you can do the water pump yourself. Dropping those pans is usually messy sine there's no convenient drain plug. It's difficult because you have to loosen all the bolts holding up the pan, the pan starts to drop and fluid starts coming over the edges all over the place, you need a huge container to catch it, etc. It sucks. I just replaced a water pump in under thirty minutes so that's probably a DIY job. However, if the $300 quote for that includes the pump, I'd have him do that too.

Fru-Gal

  • Handlebar Stache
  • *****
  • Posts: 1338
Re: Should I replace transmission drain pan & gasket myself?
« Reply #2 on: June 09, 2024, 10:00:49 AM »
Ooh sounds yucky! Thanks for your advice.

GilesMM

  • Handlebar Stache
  • *****
  • Posts: 1731
  • Location: PNW
Re: Should I replace transmission drain pan & gasket myself?
« Reply #3 on: June 09, 2024, 11:26:02 AM »
Looks fairly easy.  Not messy. 

https://www.youtube.com/watch?v=nqxc_-NjMt0

Fru-Gal

  • Handlebar Stache
  • *****
  • Posts: 1338
Re: Should I replace transmission drain pan & gasket myself?
« Reply #4 on: June 10, 2024, 04:10:46 PM »
Thanks for posting that video. My transmission pan is not that kind with the lovely, conveniently-located drain plug. It’s much flatter and the “drain plug” is a hole that was drilled then welded shut.

However I did see some videos after watching the one you posted that gave more insight (none specifically for my model, but there’s one for a 2005 Corolla that looks like my drain pan).

Turns out there is also some controversy over whether to replace the filter, whether to fully replace the fluid, whether to flush the system… I believe my mechanic said he’d flush it. Anyway more details to consider.

Paper Chaser

  • Handlebar Stache
  • *****
  • Posts: 1923
Re: Should I replace transmission drain pan & gasket myself?
« Reply #5 on: June 11, 2024, 03:23:34 AM »
If the plan is to replace the pan with a new one, then you can drill a hole to drain the fluid just as somebody did in the past. That lets you control more of the process and limit mess.

Cozzmo

  • 5 O'Clock Shadow
  • *
  • Posts: 42
Re: Should I replace transmission drain pan & gasket myself?
« Reply #6 on: June 11, 2024, 07:00:50 AM »
I would have someone change the pan and you can do the water pump yourself. Dropping those pans is usually messy sine there's no convenient drain plug. It's difficult because you have to loosen all the bolts holding up the pan, the pan starts to drop and fluid starts coming over the edges all over the place, you need a huge container to catch it, etc. It sucks. I just replaced a water pump in under thirty minutes so that's probably a DIY job. However, if the $300 quote for that includes the pump, I'd have him do that too.

A water pump in 30 mins?
Wow.. That's fast! You quite often have to remove timing belts for that. Although, I once did it on an old jeep inline 6 that was pretty easy.

I've done a lot of drain pans, they are often fairly uncomplicated.
Some cars have an easy method for re-filling, however Now, some have a complicated process.
To me, properly getting the level correct is (sometimes) the most difficult and error prone part of the job.
On some VW's, you would use the computer to measure the temperature and then top off.
Also, in my experience, it is usually NOT the pan that is leaking, but one of the input or output shaft seals.
Back when they used rubber, everything would leak and the timing belts would break, Now with Silicone, it is very rare...



Dancin'Dog

  • Handlebar Stache
  • *****
  • Posts: 1779
  • Location: Here & There
Re: Should I replace transmission drain pan & gasket myself?
« Reply #7 on: June 11, 2024, 07:19:39 AM »
I'd let the mechanic do the work since their rates are so reasonable. 

ChickenStash

  • Pencil Stache
  • ****
  • Posts: 598
  • Location: Midwest US
Re: Should I replace transmission drain pan & gasket myself?
« Reply #8 on: June 11, 2024, 08:42:53 AM »
I'm obnoxiously pro-DIY but if that $200 includes parts and labor then having the mechanic do it is probably the best bet. Replacing a pan, especially without a drain, is an annoying, messy job.

Flushing or just a refill is fine but if the filter is accessible with the pan off then it would make sense to change it then.

Cozzmo

  • 5 O'Clock Shadow
  • *
  • Posts: 42
Re: Should I replace transmission drain pan & gasket myself?
« Reply #9 on: June 15, 2024, 10:51:02 AM »
Looks fairly easy.  Not messy. 

https://www.youtube.com/watch?v=nqxc_-NjMt0

That's an engine oil pan, the transmission pan is a different thing altogether.

johnnyqnola

  • 5 O'Clock Shadow
  • *
  • Posts: 7
Re: Should I replace transmission drain pan & gasket myself?
« Reply #10 on: June 16, 2024, 09:39:23 AM »
Does the job seem easy or difficult for your car compared to other cars? I had to replace the trans solenoids on my '06 Volvo, which required dropping the subframe to which the engine is mounted and myriad other steps, just to get to the aux pan. It was 2 days of work for me, taking my time. Prob half a day for a shop. On a Civic it's a 10m job!

The nerve-wracking part was making my own silicone gasket upon putting it back together, bc an OEM gasket was $45 and would take 2 weeks to ship. I had to squeeze the RTV on and blindly maneuver the pan back into place, which was a tight fit around other components, without smearing the silicone. And I had to drop it "perfectly" into place, no wiggling it around until the bolts lined up. But I got it on the first attempt, and it hasn't leaked a drop since (of ATF anyway...it leaks everything else haha).