Waste of good ATF?? Doing

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Ramblin Fever

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10k mile drain/refills on my GM tranny; this truck currently has 191k miles original transmission with no hick-ups. Truck sees a mix of everything, including steep mountain passes, with living in Colorado.

The fluid that I'm currently draining right now, is still very very clear, red and smells perfectly normal. When I do a drain/refill, i'm only replenishing 3.5qts or so of the total 9.1qts the torque convertor holds...so I figure every 10-15k miles is good...but I'm not wasting fluid either am I?

Truck calls for Dex III, I've been using Castrol Import/Domestic ATF non-synthetic IIRC
 
It sounds like you're overdoing it. I have a GM (Buick) with 107K and I've changed the ATF twice. I dropped the pan and changed the OE fluid/filter with Mobil 1 at 36K. I changed the fluid/filter again at 96K using Mobil 1. The capacity is approx. 10 quarts and I am able to get nearly 8 of them out when I drop the pan. I'd use a good synthetic like M1, Amsoil, Redline etc... and go 60K minimum.

If I was only able to get 35 to 40% of the old fluid out like you I would d&r sooner but at 80% I think 60K (on synthetic) is a minimum.
 
If you have 191k miles, then no way is this a waste of fluid.

Stick with what you are doing and keep on driving.

Drain/refill frequency makes up for flushes.

Since DexronIII is nothing special, your intervals are perfect. If you stick with the Import(blend), or any full synthetic, you could extend your d&r intervals.

My ZF tranny, which has a viscious failure history with other owners, went over 250k miles on drain/refills at EVERY oil change using bulk ATF. My neighbor worked at the local dealer and swapped out over 100 of these units under warranty with
The problem with flushes is that wear is continual, fluid breakdown is continual, and most owners push the fluid to a point where it is useless. A simple d/r removes wear, refreshes the additive package, bumps the viscosity, and keeps you running for a long time.
 
Kind of what I thought....I figured at 191k miles and running strong, we must be doing something right. Whereas most owners barely make it to a little over 100k.

This truck is and can be used for towing at any time, it's not your typical Buick (sorry), but the truth of it is, it's a heavy truck with an under-rated tranny for the size of vehicle...so keeping the fluid fresh constantly is probably in the best interest...I'm guessing?
 
191k miles with OCI of 10k to 15k miles and u only change out roughly 1/3 of the ATF? Most definitely you are doing the correct schedule. You are not overdoing it. I would strongly recommend 10k OCI actually.
 
Today I did the second ATF/PSF extraction pump and refill with ST Dexron VI@$3.77 Qt. 2005 Corolla 57K miles. Next one in 10K sounds about right.
 
Truck is a '97 Rodeo with the GM 4L30-E transmission; running bigger tires, LSD and a locker. I don't go 4x4in too much in our mountains, but we do take good long joy rides down some pretty rough forest service roads in Colorado.

This truck does have a drain plug, what it doesn't have is a dipstick, so I have to refill it from underneith...which is a royal pain in the arse!

I've taken exceptional care of this rig, and drive it very cautiously as well...I think that's also helped.

This tranny is the 4L60-E's little brother; the 4L60 is WHAT Isuzu and GM should've put in these rigs; as the Rodeo/Troopers are heavier then the Trailblazer and some 1/2 full size trucks.

But I can't complain...haven't had any issues to date. Just very picky about how it's driven and maintenance involved.
 
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With unloaded driving you maybe over changing is a bit, but I would not change your OCI. 15k on the fluid in the pan is about right, and you are working that trans harder with the big tires.

With what you are doing there is always fresh makeup oil and that replaces the add-pac and ensures that the correct levels are always present. This is particularly important for the FM as that greatly affects clutch engagement and holding power.

The only way to tell for sure if you are REALLY way over changing the oil is a UOA. By the time you can SEE something in the ATF it's too late and it's a [censored] shoot if you can save it or not. I'd also stick to using a good quality ATF but no need to spend big money on Syn ATF in your case unless your trans runs really hot.
 
Originally Posted By: Ramblin Fever
Should mention that I've been using Castrol Import ATF...I'm guessing the quality's pretty decent??
Very good IMO!
thumbsup2.gif
 
It does say it's spec'd for all of GM Pre - 2005, believe me I made sure..I have a big thing for researching [censored] and making sure it's the right stuff even months before I actually need it.
 
AT work we had a 1997 Chevy full size van G3500, with the 4L80E and GM called for 5k mi OCI, so that is what I did. At every engine oil change I also drained out the tranny pan thru the drain plug and got 3.5l of fluid every time. I used whatever Dex III was available, Shell ATF most of the time.

I dropped the pan every 50k mi and replaced the filter. Dropping the pan only yielded an extra litre, for a total of 4.5l.

The tranny was worked pretty hard, the diesel engine being torquey and the truck being a work truck and ninety per cent of the driving being city driving.

The tranny was flawless for the life of the truck, 300k mi. It never needed any work. It did have a oil leak from the torque converter seal towards the end.

It made me a firm believer in frequent oil changes for the tranny.
 
How difficult is it? I have an 02 Isuzu Axiom, that has a THM sealed transmission, probably same as yours. I had dealer flush it at 32K, now it is at 54K miles, shifts smoothly still, but I am thinking about doing several drain/refills.
Does ATF have to be at certain temperature (I know Toyota's does), or you do you do it cold?

Thanks
 
Ramblin's truck with the GM Hydramatic transmission will do even better with Dexron-VI. It is a higher quality fluid. The other thing that would extend fluid life and maybe extend transmission life would be the installation of a larger capacity transmission cooler.

Dexron-VI is not the right fluid for a Toyota. (Did any of the Toyota/GM twins have a GM transmission, or did all have a Toyota transmission?...Aisin-Warner or other? If GM Hydramatic, then Dex-VI is OK.)
 
Originally Posted By: Ken2
Dexron-VI is not the right fluid for a Toyota. (Did any of the Toyota/GM twins have a GM transmission, or did all have a Toyota transmission?...Aisin-Warner or other? If GM Hydramatic, then Dex-VI is OK.)

I asked about Isuzu, not Toyota...
 
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