Thread: Penrite ATF-FS vs ATF-BMV

In all honesty these are not complex or' high torque ' transmissions when compared to more modern 5,6,7,8 speed offerings with secret recipe clutch materials and more reliance than ever before on Torque converter lock up for efficiency and performance, so a decent quality Dex3 4 5 or 6 will be excellent. We use the ATF FS in the GM5l40e boxes, the Toptec 1200 in the ZF 5HP24 in the L322, and LG6/8 in the 6HP and 8HP70 boxes. The reason i use LG oils in the late ZF stuff is they DO contain friction materials and bearings etc that have been co designed to use this exact oil. The earlier transmissions from the 80s 90s and 2000s (basically without a Mechatronics unit) are perfectly specced for aftermarket high quality oils such as TransmaxZ, ATFFS and Toptec versions .

Jc

disclaimer! I know zero about autos, and their inner workings and lube requirements. .. so I'm only pointing out the differences between these BMV and FS fluids.

BMV viscosity is lower .. I read it was marked as a LV(low viscosity fluid) .. but can't find the reference to it again now.
irrespective of that, it's data specs read:

Density at 15°C, kg/L	0.850
Viscosity, Kinematic, cSt at 40°C	34.0
Viscosity, Kinematic, cSt at 100°C	6.8
Viscosity Index	159
Viscosity, Brookfield, cSt @ -40°	19,839
Phosphorus, Mass %	0.017

The ATFFS data is:

Density at 15°C, kg/L	0.848
Viscosity, Kinematic, cSt at 40°C	36.0
Viscosity, Kinematic, cSt at 100°C	7.4
Viscosity Index	178
Viscosity, Brookfield, cSt @ -40°	13,000
Boron, Mass %	0.014
Phosphorus, Mass %	0.031

If I were in your shoes(which I will be very soon .. twice!) .. I'd go with the ATF-FS fluid if you want to stick with Penrite.

Note the differences in hot viscosity values(6.8 for the BMV and 7.4 for the FS).
If you look at the specs for their DexIII, the data specs are much closer in values to the FS than they are to the BMV .. especially the phosophorus mass 0.29% for DexIII.

Like I said tho, I know zero about what the internals of a auto trans need for longevity and operation, but based on the data specs of the fluids .. I'd say go with the FS(or TransmaxZ) rather than the BMV.

I get my stuff from my local R&E(walking distance) and they now know me fairly well .. and started giving me trade discount prices!
They have the Penrite stuff on the shelf, and can order Transmax Z for me(they deal with Castrol products, but don't stock a lot of their products).
So I've kind of decided that ATF-FS will do me when I do my fluid change one day soon, not so much due to it being Pentrite or the best product ...

... more so a balance of; 'this stuff is supposed to be good, AND I can get it from my local shop' at a moments notice. R&Es prices on Penrite have been good for me ... mainly because I hate stuffing around chasing the lowest possible price!