another interesting link for the 8 speed trans

http://courses.chrysleracademy.com/M.../Reference.pdf

 

Pedro,

Yes, I had already seen that document when I was doing research before buying my truck. It doesn't give any specifics on the fluid changing, though, merely stating:

"Speaking of fluid, the fluid check and fill
procedures were covered in depth in our
June 2011 release for the 8HP45. It is the
same procedure for the 845RE and 8HP70
with the exception of fluid volumes."

But what you are saying is that the fluid change has been moved completely out of the possibility of at-home maintenance, correct? I'm aware of "pumping machines" for changing transmission fluid, but this has usually been offered in the context of some fly-by-night Jiffy Lube or other business wanting to "back flush" the system without removing the pan or changing the filter. I've never had any fluid changes done by anyone other than myself, and the prospect of this makes me nervous.

Is there no way to get a complete, or nearly complete, draining of the fluid at home?

 

If you have never had a fluid change done and all you did was drop the pan then you have never actually done a fluid change, you have been mixing 1/3 clean fluid with 2/3 dirty old fluid.


There are a bunch of documented ways on the internet to make your own fluid replacement setup with some hose and a 5 gallon pail. This is one of those jobs that I just leave to either the dealer or local oil change place - not worth the hassle to me and doesn't save any money. Nobody "backflushes" transmissions any more, that was something that was done for a while and unless you find someone with an ancient backflush machine I wouldn't worry about it. Everyone uses fluid replacement machines now, which are basically just a pair of reservoirs that catch the old stuff and send back new stuff. Trans filter replacement specs are usually pretty long, because unless your trans is failing there is no reason that anything would be on the filter.

 

edited

 

So the filter in the 8-speed is not fine enough to capture any particulates caused by normal wear? Filters I've changed in the past (after 100K+ miles) usually had some type of sludge on them. The pan magnet would also have some (ferrous) sludge, but I'm assuming the stuff on the filter was probably fine stuff from the clutches.

I'll probably hit 100K in about 4 or 5 years, unless my driving patterns change. Hopefully I'll find a place I trust to do this right. JMO, but it seems like removing the dipstick and calling the transmission "filled for life" is like removing the water plugs from a battery and calling it "maintenance free" instead of "planned obsolescence".

 

It'll capture it if the clutch material actually gets to the filter. Most of the time it just sits in the bottom of the pan. I've rarely found much of anything in a trans filter, even those where the magnet is full of metal and the pan is full of clutch slurry. Pretty rare and unnecessary to worry about a trans filter before 100K, and in a lot of vehicles even after that.

 

Thanks everyone, for taking the time to enlighten me regarding the servicing of the HP70 transmission.

 

Actually, thanks for posting, some of us have been on here for sometime and served well by our early hemis (mine is an '09 and has been very reliable). Lots of folks have dropped off but I'm on so I like to hear from the new owners.