Its funny, I have dealt with many lubricants over the years and what is good for one car many not be good for another. Believe it or not Mopar has done a fairly good job with its lubricants. Some race lubricants are good for racecars but not for streetcars. I have been a victim of "snake oils" and additives. Everyone wants to have some magic liquid that will make a car run better, most are just hype and a few are good.
With the Viper, I have learned what works and what does not by seeing what happens with these various lubricants under street and track use over the past 15 years. The biggest consideration is temperature on the Viper; lubricants must be able to take the heat. Here are some basic observations.
Engine oil- Too be honest, I am not the biggest fan of synthetics, but they are crucial for the Viper. Club racers often see oil temperatures over 260 degrees, petroleum based oils just cannot deal with that. The best synthetics are those approved for European standards, which are higher than our standards. The new 5-40 Pennzoil Ultra that is designed for the new Viper is one of the best. It can be used in all the earlier models as well. The wide viscosity range makes it good for cold starts and high load. For race use, race oils offer more load protection and they have additive packages that can protect bearings if they temporarily starve for oil. These oils are primarily used on cars without catalyst as they contain high amounts of phosphorus and zinc, which can harm catalyst. So for a road car these may not be so good. The best of both worlds is the Motul 20-50 race oil, its has all the benefits of a race oil but does not seem to harm catalyst. Its higher viscosity rating would not be best for short trips and stop and go driving though.
Transmission Oil- There are several options on the lubricant for the Viper depending on the year model. It shifts best with Dexron ATF or ATF plus 4 for street use. Castrol Syntorque was factory fill for the 1997-2002 models, 2008-2010 use ATF plus 4. Syntorque's increased viscosity reduced the “neutral gear rattle” an annoying noise caused by the rough idle of the 1996-1999 Gen 2 camshaft. This oil made shifting a bit harder until it is up to temperature, it lasts longer (does not break down with heat) and makes the 5[SUP]th[/SUP] and 6[SUP]th[/SUP] gears less likely to overheat and fail during continued high speed runs (this we learned at the Silver State 90 mile races). Tremec recommends using Valvoline ATF in all their street applications but each end use manufacturer has their own lubricant. Some aftermarket lubricants make the transmission shift better but do not have the additives for the Viper specific syncroblockers and cause premature wear, so the transmission shifts great until it fails. For high hp applications that are run hard, the factory lubricants do not have the shear strength to hold the gear load. That’s when you need to run an application specific transmission fluid. These lubricants are designed specifically for load and heat, drag racing and road racing lubricants differ. Transmissions rebuilt by for specific applications come with a fluid recommendation.
Differential Oil- The differential has changed through the generations from a Dana 44 to a Super 44 and three differing types of limited slip units. The fluid has always remained the same. Differential temps go sky high with no airflow over the rear end and synthetic oil is needed.
There are petroleum-based lubricants that have much high shear strength and reduce gear wear, but they get so hot they melt the rubber diffential seals and cause leaks. Whatever you use make sure it’s a synthetic and has a friction modifier for the LSD. In aftermarket rear ends such are a Quaife, OS Giken or Truc Trac you might want to use manufacturer specific fluid. OS Giken has its own lubricant that you must use. Factory fill or Synergen seem to be the best for street and racing applications. If you race and do not have a differential cooler you made need to change the fluid more often.
Brake Fluid- You should change the brake fluid every 2 years or whenever it appears discolored. Use DOT 4 brake fluid for the street or track. In regards to SRF brake fluid, I only use this in racecars that have a brake heat issue and have a history of boiling the fluid. SRF is highly hydroscopic and will absorb moisture quite easily; therefore it requires more frequent fluid changes. What makes this fluid so good is also what makes it not so good for a streetcar. Corrosion in the brake system can happen with SRF if you do not service it every year.
Coolant- Servicing the cooling system on the Viper is very important. 1992-2002 models should have the coolant changed every 2 years and 2003-2010 models should be changed every three years. These engines run hot and are very susceptible to corrosion and oxidation. Poor maintenance can lead to leaky radiators, head gaskets and sticky thermostats. When servicing the cooling system always remove the block plugs to get all the coolant out. Use a 50/50 mix. 1992-2002 use Green coolant and 2003-2010 use red coolant. I suggest adding an anti-corrosion additive with a service. On racecars most tracks mandate only water in the cooling system. Do not use straight water and water wetter; this combination will cause extreme oxidation. Dodge’s engine warranty center (Arrow) has seen many a block ruined by this. The only way to avoid this is to include an anti-corrosive additive like that sold by BG or Wynn’s. My experience with Evan’s cool and other waterless coolants has not been good either. It seems to react poorly with rubber parts making hoses swell.
Power Steering- The power steering fluid should be changed every 12,000 miles or when it appears discolored or burnt. It also needs to be synthetic as the fluid can easily boil when tracking the car. This will melt the seals in the pump and can spew fluid onto the exhaust manifold and cause a fire. Factory fill or Red line work well. I found Royal Purple easily boils and the seals go out. ATF 4 as used in the 2004-2010 models works really well and can be used in the earlier models as well.
Hope this helps, This has been my experience, your may differ.
