Thread: Transmission oils

Guess the experts aren't on at the moment. I will be picking up one of them tomorrow. so after that any advice is to late

Edd, I'd use this one

The oil for my gearbox is
SAE 0w-20
KV@40deg c (cSt) 36
KV@100deg c (cSt) 7.1
cP@-40deg C 8400
Density@15Deg C 0.836
Viscosity 170
Pour Point(Deg C) -60
Closed Flash point (Deg C) 226

which just happens to be Transmax Z.

The other two you list are semi-synthetic at best, and while they'd work fine, I'd rather a full synth off road or towing in summer in a heavy 130.
I haven't had an auto for years, but when I did, the C6 in the F100 ran cooler with Neo and Amsoil full synth ATF than with Castrol mineral Dex II. (Thermocouple on cooler lines)

The second of the two fluids you list has a higher VI which is handy when things get hot (doesn't thin as much, up to a point), and is thinner at -40 compared to the other fluid you list, so it either has a higher quality base fluids (good) or uses a higher dose of VII's (not so good)

What are they both ? Might be able to comment better.

Transmax Z is $72 /4litres, but I'm using it in an LT77S and it is excellent.

George
Sounds like the 2nd fluid you are quoting is one of Penrites' probably the ATF Synthetic. I've never used it but with Penrites reputation I expect that it will be OK.
Anybody out there used either the Penrite ATF synthetic or the Penrite ATF BMV?

Russell

comparing pour points, VI (viscosity index) and viscosity at -40 I'm pretty sure that the first fluid has better quality base fluids, and the second one uses a lighter (thinner) base fluid 'bumped up' with a dose of VII's (viscosity index improver's) to give a higher VI (183 vs 170).
The problem with VII's is that generally they aren't near as shear stable as a good quality base fluid, and so the viscosity may fall in service as they shear.

Transmax Z, Redline, Neo, etc. don't use any VII's (which is partly why they can be used successfully as MTF's)

Havn't got the oil yet but
No one is Transmax (Castrol)

The other two are Caltex fluids.
No 1 being their Synthetic Auto trans fluid
No 2 is Texamatic 1888

I have been told my box needs full Synthetic as it will just cook the standard oils. It needs to be able to handle high temps.

Plan is to go with Synthetic Auto trans fluid

I'd use this one then

Synthetic Automatic Transmission Fluid Heavy Duty

Description
Premium performance, multipurpose anti-wear automatic transmission fluid (ATF) formulated in
ultra high viscosity index base fluid, with Allison C-4 identification and approval. Specially designed for heavy duty automatic truck and bus transmissions operating
in severe service.

Originally Posted by rick130

I'd use this one then

Thanks that's the one I was planning to get. Just wanted to be safe. Box was fully rebuilt in 04 with heavy everything. They didn't do the torque converter back then so I have now done that. Didn't like the idea of cooking the oil and being caught out after spending the $$$