Transmission cooler and thermostat (OEM and Aftermarket)

[RaleighDiesel]

Hi all!



Joined xoutpost after being in the BMW Diesel group on FB.

I drive a deleted and tuned and lowered and well-maintained 2012 X5d, but I've just recently started regularly monitoring data via BimmerLink despite having the vehicle since June 2019.

I'm seeing trans temperatures creep up to 93 degrees C and I plan to service the transmission (last service was at 95k, currently at 130k) with the ZF FCP kit, but I also want to add an additional transmission cooler. I know there is a factory unit controlled by a thermostat used to bring the transmission up to temp quicker, but is that really necessary when in a warmer climate? Car has a cold weather package (heated seats F/R and steering wheel) and when we lived in Milwaukee, WI, it was great. In Raleigh, NC, i feel like its not as necessary

My question is:
Should I plumb the cooler before the oem trans cooler thermostat or after? Is that thermostat necessary in a warmer climate?

Ideally would like to bring the operating temperature down to 75-80degC range for sanity and longevity's sake. Would like this vehicle to last me until 250k miles (hence the 35k mile trans service interval)

[RaleighDiesel]

Well, no responses but it's only been a day.

Plans include: Hadyen 679 transmission cooler plumbed into the return line to the transmission, replacing the trans cooler thermostat, and performing that transmission service. replacing the engine thermostat and a coolant flush (despite losing everything when i did the dpf delete)

and an oil change.

will update with results

[Zulu95]

From another board:
Read this thread for temperature details quoted from Ashcrofts (probably considered the leader in the ZF transmissions in Land Rovers) - Settings for the MadMan EMS alarms

Automatic transmission oil temperature:
According to Ashcrofts Transmissions, a well recognised expert in the ZF automatic transmission fitted in the Land Rovers - Transmission Oil
Absolute maximum temperature (can result in damage) - 149*C (300*F).
Maximum allowable temperature for short durations such as a hill climb - 135*C (275*F).
Normal operating temperature range - 80*C (175*F) - 94*C (200*F).
Minimum operating temperature - 66*C (once the vehicle has warmed up from a cold start).

[RaleighDiesel]

Thanks Zulu. Somebody in the facebook group mentioned that same operating range.

I was concerned because I was unable to find any concrete information about operating range/max operating temperature and seeing 93 had me worrying.

Didnt get around to all the service last weekend, but this weekend should see the trans fluid and filter changeover, cooling system service, and ATM intercooler install.

Need to start piecing together a brake system since my brembo pads and rotors have bitten dust after 18 months

[deepblonde]

Originally Posted by RaleighDiesel

Hi all!



Joined xoutpost after being in the BMW Diesel group on FB.

I drive a deleted and tuned and lowered and well-maintained 2012 X5d, but I've just recently started regularly monitoring data via BimmerLink despite having the vehicle since June 2019.

I'm seeing trans temperatures creep up to 93 degrees C and I plan to service the transmission (last service was at 95k, currently at 130k) with the ZF FCP kit, but I also want to add an additional transmission cooler. I know there is a factory unit controlled by a thermostat used to bring the transmission up to temp quicker, but is that really necessary when in a warmer climate? Car has a cold weather package (heated seats F/R and steering wheel) and when we lived in Milwaukee, WI, it was great. In Raleigh, NC, i feel like its not as necessary

My question is:
Should I plumb the cooler before the oem trans cooler thermostat or after? Is that thermostat necessary in a warmer climate?

Ideally would like to bring the operating temperature down to 75-80degC range for sanity and longevity's sake. Would like this vehicle to last me until 250k miles (hence the 35k mile trans service interval)

The E70 X5M & X6M which use the same ZF6HP28 transmission;

come standard from the factory with an additional transmission cooler as well as the standard heat exchanger used in the other e70’s including the diesels;
as well as a finned aluminum transmission sump;
Which can be fitted to replace the plastic sump used on lesser e70s,
as I’ve fitted the aluminum pan to my e70 diesel…

[RaleighDiesel]

deepblonde:

thanks for the information. I'm gonna have to find a realoem part number for that additional cooler. I returned the hayden unit since it didnt quite fit between the power steering cooler and the rad support.

[deepblonde]

Originally Posted by RaleighDiesel

deepblonde:

thanks for the information. I'm gonna have to find a realoem part number for that additional cooler. I returned the hayden unit since it didnt quite fit between the power steering cooler and the rad support.

I think I was wrong about the e70 having the additional cooler , as I looked on realoem and it showed from 2015 X5M with the additional cooler 17217849684 but that would be the 8-speed;
the E70 X5M just has the finned aluminum pan; which I fitted to mine .