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Transmission Fluid - 173K..To change or not to change, that is the question

99XC600

99XC600

New member
Ok, I've owned my 2004 GT1 since it had 8k on the odometer. It currently has 173k miles on it. The transmission fluid has never been changed nor have I ever had to add anything to it. (Yes, I know please begin the verbal abuse). I have no signs of slipping or hesitating at all. However I've never beaten on the thing either. It's my DD which I put 80 miles on every day with it being 95% highway.

So as I was addressing the LIM gasket issue over the weekend, I started to ponder the changing of the tranny fluid. I don't know what I should do. Since it's not showing any signs of failure, should I just leave it be or go ahead and change it. I've heard story's of high mileage tranny's going south after recent fluid changes.
 


Mine's at 172k and I'm pretty sure it's never been serviced. I'm about to do a pan drop and filter change and fill with new fluid. I'm pretty sure it's the flushing you want to avoid. You should be fine changing the fluid.
 
Just do a pan drop and not a flush and you'll be fine. Check for metal shavings when you do the pan drop...if you have some..plan on getting a tranny down the road if it fails.
 
depending on how hot you get ur tranny. max at best conditions is every 100k.... so ur a little over that. it is a cheap simple thing to do. i would do it soon if ya care about the tranny lol
 
Wish I could tell you, but I have the worthless 3 button DIC in my car. So no real idea of the tranny or coolant temps.
 
I am paraniod I change mine once a year just do a pan drop, every other year I change the filter as well 301,000 miles on trans
 


As a practice over the years, when my tranny pan doesn't have it, I've been adding a drain plug. I got spoiled with the 4L80E's and some older truck trans that had them so I just bought them and put one in. Before I started adding the plugs, I normally changed the filter and fluids every 75k or so. Now I run the filter for 100k and make the fluid change around 50k........besides the plug makes draining a lot cleaner and easier.......wish they did them at the factory.
 
bloaty57 said:
As a practice over the years, when my tranny pan doesn't have it, I've been adding a drain plug. I got spoiled with the 4L80E's and some older truck trans that had them so I just bought them and put one in. Before I started adding the plugs, I normally changed the filter and fluids every 75k or so. Now I run the filter for 100k and make the fluid change around 50k........besides the plug makes draining a lot cleaner and easier.......wish they did them at the factory.
Click to expand...
how do you add that? welding? sounds nifty...
 
Sounds like I should be pretty safe.

I think a lot of the horror stories come from transmissions that are already displaying some type of a problem and the owner changes the fluid in an effort to correct the problem. The changing of the fluid just ends up compounding the original issue.
 
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99X is right.........sometimes the gritty nature of the old fluid is what's keeping the thing running. I've seen exactly what he said happen.......change the fluid and the thing starts screwing up big time. Also pressure flushing is a big no-no........

bmx.....yeah, it's fairly simple and straight forward. Buy a shallow bung kit and pick a spot in the pan that doesn't have anything above it, or in close proximity and either drill or punch a clean hole that "just allows" the bung to fit. I mig mine in, but they do make one that has an inside flange and outside threads with a thin thread on nut/collar. It comes with a thin brass O ring washer. Layer on some red locktite and snug it up....good to go. Never seen or heard of them leaking, but I prefer the weld in ones. Most guys don't bother and I can appreciate that, but knowing stock clutches like I do, I like to get some of the crap out in the interim. The quality filters are usually good for 100k or so, but having the ability to change the fluid in between stretches things a bit more.
 


my brother and i just did a pan drop, filter, and then a flush to his yukon a few weeks back. he's low miles, ( around 60,000) but still the magnet was caked with clutch material. like a mound of it.

his trans fluid was still very red, and had no burnt smell, so we did the flush and its running just fine.


so what im saying here is when you drop the pan, the magnet in the pan will be telling a big story. thats a lot of miles for a un serviced trans.

it may also be a good idea to to put a quart of lucas trans medic in the the trans as you re fill it. it tightens up old clutches. freshens up seals and such.
 
I have 149k miles on mine and added a screw in bung (from Checker) at about 25k miles. It's never leaked a drop and makes changing trans fluid a million times easier. Sure, you can tig a bung in, but the screw in one I have has 125k miles on it without a single issue. I highly recommend it....
 


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