Quick ZF5HP24 question..

[turquise1]

Here is something interesting I came across today as I was doing more reading. Someone with similar symptoms was told to check out a piece called 'pump volume control valve'. This part seems to be adjusting the pressure before the fluid gets to the valve body.



Is it worth looking at? Is is accessible without pulling the transmission (looks like it's kept in there with a bolt)?.


Thoughts?


Thanks,


Ozzie

[RRPhil]

The required pump displacement (in this case, 16cc/rev) is set by the flow requirement at tickover.



As the 5HP24 uses a positive displacement pump, when the engine revs rise there is an abundance of flow, much more than the transmission needs, and the flow regulating valve serves to cap this at 48 litres/min.



The clever bit is that, rather than simply bleed the excess flow off to the sump (as stated, incorrectly, in the ATSG document that you attached), the flow is actually diverted back to the suction side of the pump so that it is recirculated and therefore the power used to produce the excess flow is not wasted. This also reduces cavitation in the pump and therefore noise.



I personally have never come across a single instance of a problem with this valve, but I guess there would be no harm in removing it to check.



The uncompressed spring length should measure 82mm. You may struggle to get the actual piston out, because it’s a very close fit in its bore.

Phil

[turquise1]

Thank you Phil, I knew you were following.

I also know I will have to replace the darn transmission eventually but I would like to look at everything else before I will have to do that. (also waiting for Chicago weather to warm up)..


Cheers,


Ozzie

[turquise1]

Here is a quick photo of what I saw inside the bore. The spring looked ok but I had trouble taking the piston out. It felt stuck in there. I will try again soon.



Thanks,


Ozzie

[crystalworks]

How much total fluid have you put into the trans? My zf 6hp19z took a full (every drop) 7 liters to fill.

Fill procedure:

1. remove fill plug and fill trans while cold, engine off (took 3.25 liters), install fill plug
2. start engine and run it for 30 seconds, shut off, remove fill plug and fill more (took 2 liters), replace fill plug
3. start engine and monitor trans temps, at 30C start cycling through the gears while the trans warms up
4. at 40C, leave the engine running, remove fill plug and fill the trans again (took remaining 1.75 liters), when a stream is coming out replace fill plug and torque to spec (6hp19z is 24ft lbs)

If at any point the trans reaches 50c, insert the fill plug and wait for the trans to cool back down to 40c. The goal is a small stream coming out at 40c.

[upallnight]

Originally Posted by crystalworks

How much total fluid have you put into the trans? My zf 6hp19z took a full (every drop) 7 liters to fill.

Fill procedure:

1. fill trans while cold, engine off (took 3.25 liters)
2. start engine and run it for 30 seconds, shut off and fill more (took 2 liters)
3. start engine and monitor trans temps at 30C start cycling through the gears
4. at 40C fill the trans again (took remaining 1.75 liters)

If you are stopping the engine to fill it, you are doing it WRONG.

Filling a trans that has been drained, you fill the trans with th engine off until it starts to come out the fill hole. Place the plug back onto the pan and start the engine up, Go through all the gears with the engine running. With the engine still running (trans in PARK) remove the fill plug and pump ATF into the trans until it start to come out of the fill hole. The temp shouldn't exceed 35C. Once th temp is at 35C replace the fill plug back into the trans. At this point, the trans fluid should be at the correct level. The engine needs to be running so that the trans pump is turning. Shutting the engine off with the fill plug out will cause ATF to be dump out of the trans.

[crystalworks]

You can do it either way. I didn't want to have to pump ~4 liters into the car with it running. Adds more opportunity to overshoot the 40c-50c on the trans that ZF calls for. Starting the engine for 30 seconds gets the pump to circulate what you put into the pan through the trans so you don't have to do the whole fill with the car on.

As to the 35c number. As above, ZF disagrees with you. My trans is shifting better than before at 186000 miles. Soooooo... what can I tell you? The method I used works, and is used by others as seen below, again on the 6hp19z.

https://www.bmwrepairguide.com/bmw-e...es-all-models/

That said, ZF also wants 40c for final fill. I did not put in my instructions when to remove or install the fill plug as I thought it was obvious, I'll edit the post to add it in to avoid confusion.

[turquise1]

Originally Posted by crystalworks

You can do it either way. I didn't want to have to pump ~4 liters into the car with it running. Adds more opportunity to overshoot the 40c-50c on the trans that ZF calls for. Starting the trans for 30 seconds gets the pump to circulate what you put into the pan through the trans so you don't have to do the whole fill with the car on.

As to the 35c number. As above, ZF disagrees with you. My trans is shifting better than before at 186000 miles. Soooooo... what can I tell you? The method I used works, and is used by others as seen below, again on the 6hp19z.

https://www.bmwrepairguide.com/bmw-e...es-all-models/

That said, ZF also wants 40c for final fill. I did not put in my instructions when to remove or install the fill plug as I thought it was obvious, I'll edit the post to add it in to avoid confusion.

Thanks guys. In any case, I do not think my issues are related to fluid levels since my R now shifts without a delay but D from P or N still has a delay and I still have engagement problems.


What is interesting is when I start the car in the morning, I actually have no delay on engagement for 2-3 minutes. I can put the car on gear and go until the issues start once it slightly warms up. And once the transmission is at working temp, at one point it starts working nicely and no more issues.


Right now, I am looking around for a used ZF5HP24 to rebuild and replace it with the one on the car. I will keep posting with the updates..


Thanks again,


Ozzie

[turquise1]

Originally Posted by upallnight

If you are stopping the engine to fill it, you are doing it WRONG.

Filling a trans that has been drained, you fill the trans with th engine off until it starts to come out the fill hole. Place the plug back onto the pan and start the engine up, Go through all the gears with the engine running. With the engine still running (trans in PARK) remove the fill plug and pump ATF into the trans until it start to come out of the fill hole. The temp shouldn't exceed 35C. Once th temp is at 35C replace the fill plug back into the trans. At this point, the trans fluid should be at the correct level. The engine needs to be running so that the trans pump is turning. Shutting the engine off with the fill plug out will cause ATF to be dump out of the trans.

Is there a particular reason that the filling procedure should start after 30c other than the fluid expansion which may cause overfilling when the transmission is hot?



Just curious..


Thanks,


Ozzie

[RRPhil]

Originally Posted by turquise1

Right now, I am looking around for a used ZF5HP24 to rebuild and replace it with the one on the car.

I’m sure you already know, but just to emphasise that you need to make sure you get a 1058 000 029 model and not a 1058 000 034 (which is for the 4.6is).



Also, be sure not to get the 1058 000 032 model for the 4.4 V8 M62-engined L322 Range Rover, as it will not fit your E53.



Phil