MDX Rear Diff - Leave FF in or Change To DPSH

[artbuc]

I've read many, many threads re Z-1vs DW-1 vs DPSH here and elsewhere. However, I have not seen the answer to my question. My MDX has 18 k miles. Would I be better off leaving in the FF Z-1 or should I change to the Acura DPSH all wheel drive fluid?

I question if the DPSH is as good as the Z-1. Seems like Acura had to abandon Z-1 for some manufacturing and/or environmental issues. They tried to make the best of things by inventing DW-1 ATF and claiming superior low temp performance in the tranny. However, DW-1 won't work in the rear diff so they had to invent DPSH. Is the DPSH replacement a hastily cobbled together stop-gap or is it an upgrade over Z-1? I have this bad feeling that Acura is going to tell us in a few years that we should dump DPSH and start using a new fluid which they are working on right now because they know DPSH ain't good enough. Thanks.

 

[chubbs1]

I would leave the FF in there for now and if you were going to change it in time I would use true syn gear fluid equivalent from Redline or Amsoil. You can't go wrong with their gear/tranny fluids.

 

[meep]

NO NO NO

The MDX rear diff requires honda's dual pump fluid. don't substitute anything else in there; it's a very finicky system.

also, check your manual, the service life for the fluid is longer in some honda's than others.... in the MDX it's either 15k or 30k... and I want to say it's 15k. So it may be overdue.

I would NOT run this fluid longer than mfr interval. it get's pretty beat up in their other mechanical (the mdx is electro-mechanical) AWD apps.

check your manual, and this is the one-and-only case you'll ever hear me vehemently (my opinion of course) say to stay oem.

 

[gogozy]

is yours a 2G MDX with SH-AWD (2007-2010 prior to 6AT)?
yes, the rear differential spec ATF-Z1 originally, and now Honda spec DFSP. this thread may answer your question
so my understanding is that DW1 is too thin.

 

[artbuc]

Originally Posted By: meep
NO NO NO

The MDX rear diff requires honda's dual pump fluid. don't substitute anything else in there; it's a very finicky system.

also, check your manual, the service life for the fluid is longer in some honda's than others.... in the MDX it's either 15k or 30k... and I want to say it's 15k. So it may be overdue.

I would NOT run this fluid longer than mfr interval. it get's pretty beat up in their other mechanical (the mdx is electro-mechanical) AWD apps.

check your manual, and this is the one-and-only case you'll ever hear me vehemently (my opinion of course) say to stay oem.


Not sure where you are getting the diff fluid change interval. My Owners Manual does not give intervals - it says to follow the MM. Are you referring to the factory Service Manual?

 

[gogozy]

owner's handbook of 2009 MDX, page 390. it is an indication that Honda want owner to flush out factory fluid early. I am currently using Amsoil ATF in the unit and will switch to Redline D4 when my Amsoil stash runs dry. I had did 2 drain and fill, the 1st differential drain of ATF-Z1 around ~12000-14000km (sorry cant remember..) has some paste on magnet plug, but no where near the amount the transmission plug has collected. the car is Z1 free for 20000km now and I only felt it drive better, however, i do not have measurable data available (such uoa or voa or dyno to back it up). I drain and fill both every year. as unDummy explain in the pasted link, the DW1 was likely too thin for differentials; too me about few month to realize/understand... If I got another SH-AWD equipped car, I would change out ATF and differentials fluid as soon as I can, and definitely earlier than 12,000km.

2009 MDX owner's handbook from Honda, page 390
"Replace rear differential fluid
Driving in mountainous areas at very low vehicle
speeds or trailer towing results in higher level of
mechanical (shear) stress to fluid. This requires
differential fluid changes more frequently than
recommended by the maintenance minder. If you
regularly drive your vehicle under these conditions,
have the differential fluid changed at 7,500 miles (12,000
km), then every 15,000 miles (24,000 km)."

 

[meep]

Originally Posted By: artbuc
Originally Posted By: meep
NO NO NO

The MDX rear diff requires honda's dual pump fluid. don't substitute anything else in there; it's a very finicky system.

also, check your manual, the service life for the fluid is longer in some honda's than others.... in the MDX it's either 15k or 30k... and I want to say it's 15k. So it may be overdue.

I would NOT run this fluid longer than mfr interval. it get's pretty beat up in their other mechanical (the mdx is electro-mechanical) AWD apps.

check your manual, and this is the one-and-only case you'll ever hear me vehemently (my opinion of course) say to stay oem.


Not sure where you are getting the diff fluid change interval. My Owners Manual does not give intervals - it says to follow the MM. Are you referring to the factory Service Manual?


yes, factory maintenance schedule... the smaller book that comes with the owners manual. ours is a gen 1 so if the newer system is different my statements might not apply, but I didn't see a year listed in the OP.

 

[artbuc]

Sorry, I have a 2010. I'll check the other book (I don't remember seeing it) and let you know what it says. Thanks.

 

[artbuc]

My maintenance supplement booklet does not say anything about diff change interval other than that noted earlier when driving in mountains and/or towing, neither of which applies to me. Don't know if it correlates, but booklet says change TB at 60k if driving in severe conditions (low/high temps or towing) and I think normal TB change would be 105k. So I don't know when the MM will tell me to change diff fluid but I ordered some DPSF and will change it now just because I am totally anal about my cars. I will also be changing brake fluid now (2 years) even though booklet says every 3 years. No way I am letting BF stay in my car for more than 2 years.

 

[meep]

i believe the 2010 still uses the same electro-mechanical dual-clutch system that the earlier MDXs, ridgelines, and pilots use. It's NOT a diff but simply a ring and pinion with individual L-R clutches that experience controlled slip all day long.

In the CRVs the fluid was good for 60k, but it was a true diff with a single hydraulic limited slip clutch on the input shaft and wasn't exercised unless there was enough variance between F/R wheel speeds.

However the 'X's have a more aggressive system, and I'm almost certain our gen 1 calls for a 15K interval. I think you are doing right by getting the "dual pump fluid" (the original AWD in the CRVs used dual pumps to create pressure differential --> clutch actuation) and changing it. It has to lube gears, bearings, keep the clutches cool and carry clutch debris.

and I would agree to NOT run something else in there, unless the design has changed and calls for a different fluid.

It's not a hard job. drop the spare for better access, and you may need a 1/2 extension and decently long bar to break the plugs loose.

M

 

[gogozy]

from 2005 RL to 2009 MDX, RDX, ZDX and certain month of 2010 model til Honda switch to ATF-DW1, all these rear differential were filled and spec for ATF-Z1. the dual pump fluid is on HONDA RT-AWD such as Ridgeline, Pilot, CRV, Crosstour. I don't have experiences with fluid use on Honda VTM, all SH-AWD differentials were calling for transmission fluid ATF-Z1 since beginning til Honda switch to ATF-DW1. after ATF-Z1 supersede by ATF-DW1, Acura back-spec "Acura DPSF" as the fluid for new and old SH-AWD differentials. There has been some debate on weather Acura DPSF is the repackaged Honda DP2 (DPII) fluid. I believe the desire of viscous fluid is the reason ATF-DW1 not being spec for differentials. I am continue using transmission fluid as it's was originally calling for. I also do not recall change to the differential unit from 2007 to 2011 according to the parts diagram.

as for interval, it's not something new for manufacturer to reduce the intervals. owner handbook of 2004 TSX says it does not need to change transmission fluid til 160,000km. but Honda change it on 2005 or 2006 model and shorten it. i guess it all depend if you like to keep the car long or not.

 

[artbuc]

Originally Posted By: gogozy
from 2005 RL to 2009 MDX, RDX, ZDX and certain month of 2010 model til Honda switch to ATF-DW1, all these rear differential were filled and spec for ATF-Z1. the dual pump fluid is on HONDA RT-AWD such as Ridgeline, Pilot, CRV, Crosstour. I don't have experiences with fluid use on Honda VTM, all SH-AWD differentials were calling for transmission fluid ATF-Z1 since beginning til Honda switch to ATF-DW1. after ATF-Z1 supersede by ATF-DW1, Acura back-spec "Acura DPSF" as the fluid for new and old SH-AWD differentials. There has been some debate on weather Acura DPSF is the repackaged Honda DP2 (DPII) fluid. I believe the desire of viscous fluid is the reason ATF-DW1 not being spec for differentials. I am continue using transmission fluid as it's was originally calling for. I also do not recall change to the differential unit from 2007 to 2011 according to the parts diagram.

as for interval, it's not something new for manufacturer to reduce the intervals. owner handbook of 2004 TSX says it does not need to change transmission fluid til 160,000km. but Honda change it on 2005 or 2006 model and shorten it. i guess it all depend if you like to keep the car long or not.


Are you concerned that DPSH will lead to premature failure? How did you select Amsoil ATF for your differential? I am concerned about using DPSH but must while I am under warranty. Thanks.

 

[gogozy]

I am not concern about DPSF cause failure. just want to point out Acura DPSF probably is not the Honda DP2 fluid, even their part # are very close, SH-AWD differentials also does not take VTM nor DP1 fluid.

back in early 2010, there was only the weak ATF-Z1; no DPSF nor ATF-DW1. I had use Amsoil ATF since it list as equivalent to the ATF-Z1.

 

[meep]

Originally Posted By: gogozy
from 2005 RL to 2009 MDX, RDX, ZDX and certain month of 2010 model til Honda switch to ATF-DW1, all these rear differential were filled and spec for ATF-Z1. the dual pump fluid is on HONDA RT-AWD such as Ridgeline, Pilot, CRV, Crosstour. I don't have experiences with fluid use on Honda VTM, all SH-AWD differentials were calling for transmission fluid ATF-Z1 since beginning til Honda switch to ATF-DW1. after ATF-Z1 supersede by ATF-DW1, Acura back-spec "Acura DPSF" as the fluid for new and old SH-AWD differentials. There has been some debate on weather Acura DPSF is the repackaged Honda DP2 (DPII) fluid. I believe the desire of viscous fluid is the reason ATF-DW1 not being spec for differentials. I am continue using transmission fluid as it's was originally calling for. I also do not recall change to the differential unit from 2007 to 2011 according to the parts diagram.

as for interval, it's not something new for manufacturer to reduce the intervals. owner handbook of 2004 TSX says it does not need to change transmission fluid til 160,000km. but Honda change it on 2005 or 2006 model and shorten it. i guess it all depend if you like to keep the car long or not.


Interesting. I wonder what changed. the dual pump fluid isn't cheap but seems to hold up well. The manual for our 01 mdx calls out the DPF for the rear so that's what I'll roll, but it's good to hear they went to DW1 in the later years. Never been impressed with Z1 and almost always put amsoil in a honda if it happens to have its hood up in front of my house.

Mike

 

[artificialist]

I would change it at 15,000 miles simply because that is when the majority of the wear metals is created.

 

[artbuc]

Originally Posted By: artificialist
I would change it at 15,000 miles simply because that is when the majority of the wear metals is created.


Agree. My DPSF is on the UPS truck right now and I should have it by 5pm.

 

[artbuc]

2010 MDX

Replaced factory Z-1 with DPSF today at 18.8k miles. There was enough debris on the drain plug to leave a black smudge on a white cloth but no discrete particles big enough to see. Factory fill looked fresh and pink. There was definitely NO need to change this fluid so early. Oh well, at least my curiosity has been satisfied.