Honda VTM-4 (rear diff) fluid VOA

[bulwnkl]

I haven't seen a VOA of this fluid, which is specified by Honda for use in the rear differential on certain of their all-wheel-drive models. The Ridgeline pickup is one example of a vehicle which uses this rear end box. There is an explanation of this diff from the lead engineer on the Ridgeline platform, including some cutaway views, located HERE and HERE.
This is a very interesting fluid to see in a rear diff because it's the same viscosity as an LV ATF.

Fe: 0
Cr: 0
Pb: 2
Cu: 0
Sn: 0
Al: 0
Ni: 0
Ag: 0
Si: 4
K: 2
Na: 1
B: 262
Mg: 226
Ca: 377
Ba: 0
P: 272
Zn: 347
Mo: 0
Ti: 0
V: 0

Visc (100C): 7.2 cSt

I'd wanted a V40 as well. I'll try to get that and post it up here.

 

[HangFire]

Thank you for posting that!

I changed my Pilot's VTM-4 with genuine Honda fluid and never had a problem with it, finally sold the vehicle at 214K with the rear diff working just fine. It is one of the few fluids that everyone agrees, there is no substitute. (I have no clue if this is true, but at a small amount every 30K miles the genuine Honda fluid is affordable enough not to bother trying).

That vehicle's ability to climb a steep, wet, ice glaze covered driveway on all-seasons was amazing, zero drama. My 2005 did not have the "SH" (Super Handling) option.

 

[bulwnkl]

I'm glad to hear it was durable for you! Most of my use of my Ridgeline isn't hard on the rear end, but I do like to go to the mountains and onto ‘roads' that the pickup can only barely pass over, so occasionally the diff works hard.

Molakule or others, what are your thoughts on this diff fluid?

Here's an image for those who prefer that:

 

[MolaKule]

Originally Posted by bulwnkl

Molakule or others, what are your thoughts on this diff fluid?



It appears very similar to the Dexron (III-H)/Mercon fluids although it may have some unknown goodies we cannot see in this analysis.

I suspect it contains some Group IV and advanced Group V proprietary base oils now being used in advanced gear lubes.

In the cutaway view, I see two things:

1. The Bevel Driven gear and the Drive Pinion are at right angles and are not oriented in an off-set configuration as in many differentials. This means reduced tooth loads at the Bevel Driven gear/ Drive Pinion interface.

2. The magnetic clutch is attached to a Wet Clutch pack for differential torque application which appears to be wetted and floating in the 7.5 cSt fluid.

 

[bulwnkl]

Great input; thanks, Molakule!

The lab got me the KV40: 30.2
A simple online calculator puts VI at about 216

For any who care about such things, the 1-gallon jugs that this fluid comes in say that Idemitsu USA manufactures it for Honda.

 

[MolaKule]

It also contains to what appears an AW level of ZDDP. The EP appears to be a potassium borate additive.

The magnesium and calcium levels appear to be levels sufficient for friction modification in order to attain a a specific friction coefficient for the variable torque clutch.