Hyundai Genesis Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
787 Posts
Discussion Starter #1
So... has anyone attempted a ZF auto transmission drain/refill? I'm not talking about a complete flush or filter/drain pan replacement. Just a drain and fill.

Those of you who track the car for fun should be looking into this. Hyundai says the fluid is good for a lifetime but nobody knows what "lifetime" means. 100k miles under normal usage? How about 200k? What if you track the car? At higher rpms you're creating a lot of heat in the transmission. Heat that ultimately degrades the 'lifetime' synthetic fluid.

Here's a DIY from a BMW forum for the 6hp19z (bmw specific) version:
DIY ZF 6HP19Z Transmission Drain & Refill - 5 Series Forums

The hyundai service manual only mentions inspection of ATF level. This requires warming the transmission up to a certain temperature and then checking to see if fluid exits the filler hole. Fluid specified is Shell M-1375.4

There is no mention on draining the fluid. Torque specs on the drain bolt is unknown.

Any thoughts?
 

·
Registered
Joined
·
37 Posts
Vox,

I was thinking about doing this for my 30k service. The shop manual has the torque listed. Using a TORX wrench, install the filler plug. Tightening torque : 35 Nm(3.5 kgf.m, 25.3lb-ft)

I believe you simply have to pump in new fluid and wait until it stops running out, but I have no idea how much.

Jim
 

·
Registered
Joined
·
787 Posts
Discussion Starter #3 (Edited)
The listed torques are all for the filler plug. Not the drain plug. The manual makes no mention of flushing or draining the fluid.

On most transmissions you just fill until the fluid leaks out the filler hole and then you're done. ZF calls for a specific temp range when filling.

But how do we determine that temp? It's not like we can stick a thermometer up the exhaust of the car and call it a day...
 

·
Registered
Joined
·
100 Posts
i flushed every fluid in the car and replaced it with royal purple at 7000 miles. the auto tranny locks up in 3rd or 4th gear at high temps during track conditions even with upgraded fluids. we are installing an rx7 oil cooler for the tranny to fix the issue. as far as torque used for the bolts and the process ive no idea. we flushed the tranny and put new royal purple @ 22000 right before a two day NASA track event where the car was run over 3 hours on the track in 20 min intervals every thirty minutes for two days and still had the tranny issues. idk, i replace every fluid after every major event.
 

·
Registered
Joined
·
787 Posts
Discussion Starter #6 (Edited)
the car was run over 3 hours on the track in 20 min intervals every thirty minutes for two days and still had the tranny issues. idk, i replace every fluid after every major event.
By lock up you mean the car shifts early? That's going to be the fluid overheating. Only an upgraded tranmission oil cooler will alleviate that. Unless you mean something else.

...

Anyway. Found the torque spec for the drain bolt. 8Nm per ZF's 6hp19/21 parts catalog:


The fill process has a goddamn logic flowchart. :rofl:

Apparently transmission temperature is read via some sort of scanner you plug in. No mention of what that scanner is, where it's plugged into, or how much it costs (don't want to know.)

Per NCZ13's help it seems like there are OEM part #'s for both the drain and fill plugs in the case that they should be stripped/rounded out while working on them (they are allen/torx head not socket.)
 
1 - 6 of 6 Posts
Top