Canadian Hummer Club Forums

What do you guys recommend. To simply change the fluid or do a transmission flush? I want to change to Amsoil Torque Drive and was thinking to get a transmission flush ?


Let me know

Do a transmission flush! You need to get the old oil out of the cooler and torque converter otherwise you are only changing less than half your transmission oil!

Thanks for the reply . I've had several people to tell me not to flush as it will ruin the transmission. My mechanic said they use a a machine that uses the transmissions own pump to flush out the tranny so no extreme force is used. However people are telling me that if the sediment is cleaned out the gears will clash and not shift .. Anyways I am still going to get it done.

Sorry forgot to ask .. When flushing the transmission how much transmission fluid will need to complete the flush and fill it back up.

Ok normally if your transmission oil is burnt, I would actually tell you to leave it alone. Putting new transmission oil into a transmission that has burnt oil will normally finish it off very quickly!

However IF you transmission has never ever ever had a service done in over 160000km then again I would suggest that you just leave it. Most of the seals are hardened and you might cause an internal leak even if the oil is still reddish and cleanish.

If your current oil is still reddish and you have records of previous transmission oil changes then you should be good.



Now question for you, Is your oil Black or Burnt? Does your transmission have more than 160000kms without having had a transmission service?

I checked the fluid and it's clear pink with a tinged of brown in it. It currently has 220km highway mileage with 2100 hours on the original engine. I don't have previous records but appears the hummer has been a street queen. The transmission currently shifts smoothly. Not knowing previous records is why I am getting everything changed. My mechanic said he could also just do a tranny fluid change and not do a flush if I prefer and he will change filter and gasket as well.

Don't put the Amsoil Torque Drive just use standard ATF. Do not do a flush only change the oil and filter. And you should add a seal conditioner.


My apologies I should have asked all of the important questions at the beginning!

Thanks for the info. I have already ordered the Amsoil for tranny and transfer case. Now in standard ATF do you mean the dextron vi or the transfer case fluid which is dextron iii. How much tranny fluid is needed if you just change it by draining it. Can I still use torque drive since I have it?

Standard ATF = Dexron III only


You would need about 4 liters


If you decide to use the torque drive use a transmission oil conditioner to help rejuvenate the seals so your transmission will continue to bs happy!

Heard bad things about machine flushing and crap getting in.
I do a DIY gravity flush every 60 k miles.
In addition i do standard filter/fluid every 20k miles on trans and t case based on extreme duty servicing protocols.
For the flush, basicly 12 quarts in 12 quarts out. I feed fluid into the dipstick hole and drain from the oil cooler return line. 
With E brake on wheel chocks the engine running and moving through the gear positions a few times you will get most of the old stuff out of the torque converter,valve body and the cooler.
I hang my fluid from the roof with a clear tube down to the trans filler tube. As soon as i see the tube run clear down blow the dipstick hole i shut off the engine, get under the truck and close up the cooler return line once the level is good.
For seal leaks running a bottle of Lucas Trans Fix for a few hundred miles prior to changing out your filter and fluid will help swell up and soften the seal rings.
There is always a risk that when changing to new fluid that the detergents and scrubbers in new fluid can disintegrate seals, clutches and even bearings if they are in old questionable shape to begin with.
My biggest worry with the 4L is water getting in via the dipstick seal on the upper edge of the trans body. Instant kill evidenced by peanut butter fluid.