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Do you have to heat your Diff Oil in microwave before you can pour it into your diff casing?

  • Do you have to jack your truck up and run the diff on stands for 10 mins before each race?

  • Ever wondered why your TT or ULTRA 4 Diff blows up when running thinner oils?


How many Trophy Trucks and Ultra 4 Cars do you see with Oil Coolers Fitted to the Differentials? Not many? Why is that? The Imagineers at Proformance have often asked why race teams in the USA all seem to run an incredibly thick oil (we call it grease) that is so thick they need to heat it up before it can be poured into the diff housing

The oils used in off road motorsport are SO THICK that competitors are forced to heat the diff cases with a Gas Blow Torch whilst the trucks are elevated on jack stands, with the engine running so that when they start the race the "grease" in the diff will be hot enough that it will actually act like an oil instead of a thick paste.

If you are running a thick 250 Weight Oil ("Grease") in your diff, then perhaps you should investigate what temperatures your diff is running at. A diff running 75/90 oil and an oil cooler will result in the oil being "thicker" with a higher viscosity than a vehicle that is running 250 Weight "Grease" at higher temperatures.

It's simple maths. 250 Weight or Higher oils (Grease) are often being used as a bandaid by many off road competitors because the diffs are simply getting too hot and typical diff oils are becoming too thin to provide adequate lubrication and protection properties.


It is common industry knowledge that the super strong Ford 9 Inch and 10 Inch Diffs run MUCH MUCH hotter than the DANA Diffs bceause the 9 inch and 10 inch diffs have a MUCH lower Hypoid Offset, resulting in a much lower efficiency and robbing horsepower. Even if you are running a 10" Race Prepared Diff that generated lots of heat, the temperature can be effectively controlled with an oil pump and oil cooler to protect the oil and prevent the need to run silly, thick grease in your $30,000 Tube Works Diff.

Controlling the temperature of the oil in the Diff will allow the use of higher quality oils and prevent the need for heating the diff up before events.

If a competitor was to run a temperature sensor on his 10" Diff, and look up the viscosity of the 250 weight oil running without an oil cooler it would be obvious that the viscosity of the 250 Weight oil will be a lot thinner than a 75/90 Diff oil running at a cooler temperature.


Throwing 250 weight oils in your diff without a cooler and hoping it does not blow up is just bandaid a to the real problem.

Do yourself a favour, mesure and monitor the temperature of your diff at your next event then look up the viscosity (Centistokes) of your oil at the maximum operating temperature your diff experianced. You will be amazed how thin your oil will be getting at high temperatures. Thick oils, EVEN 250 weight grease,will become thinner than water at extremely high temperatures.

A better option is to use a tempearture controlled oil pump to send the oil up to an oil cooler (As above) and keep the oil nice and thick ALL THE TIME.

In summary, a vehicle running a Diff Cooler with 75/90 Diff oil will have THICKER oil viscosity and better diff gear lubrication and protection from failure than a truck running 250 weight oil at high temperatures - simple.

Again - Follow the Flock, or make an Informed Decision and fix the problem.

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