A reader asks: I’m doing the three main fluid changes in my 2005 Harley Fatboy. For the primary, I have used AMSOIL Synthetic ATF in the past. Is that a good choice?
Our answer: The use of automatic transmission fluid in Harley-Davidson primary chaincases has been a hotly debated issue for many years. Automotive ATF would not be our choice.
Why Do Some Use ATF In H-D Primary Chaincases?
This practice seems to have originated in the aftermarket clutch market and drag racing community. One of the main reasons is that the thinner ATF will allow the clutch to grab harder during aggressive riding.
Some aftermarket clutch-makers suggest ATF meeting the Dexron III spec, while others suggest Ford “Type F”.
We spoke to one aftermarket clutch-maker who suggested that Harley-Davidson Primary Fluid did not perform well with their Kevlar clutch plates. They claim that ATF is more compatible with their clutch plates (more on Kevlar clutch plates below).
We submit that ATF is too thin for Harley primary use. It’s true that many Harley riders have had years of problem-free performance with ATF. We contend that a thicker oil will provide superior metal-to-metal wear protection. Chains and sprockets will last longer using a fluid with an appropriate viscosity.
Below are the kinematic viscosity numbers for AMSOIL Signature Series Multi-Vehicle Synthetic ATF, AMSOIL V-Twin Synthetic 20W-50 and AMSOIL V-Twin Synthetic Primary Fluid. The viscosity is measured at 100°C.
ATF- 7.5 cST
20W-50- 18.5 cST
Primary Fluid- 18.7 cST
Compared to 20W-50 motorcycle oil and the dedicated primary fluid, ATF is very thin. For reference purposes, ATF has a similar viscosity to 5W-20 motor oil.
The AMSOIL V-Twin Primary Fluid is an SAE 90. Some may wonder how the 20W-50 and 90-weight primary fluid have a similar viscosity. The reason is that gear oils and motor oils are given different viscosity numbers on the label to prevent confusion. But in terms of the actual viscosity measured in the lab, they are very close.
In conclusion, if you have a stock clutch, use a dedicated primary fluid or a suitable 20W-50. If you have an aftermarket clutch, we would still submit that a good synthetic primary fluid is the better choice.
If you have a Ram 1500 pick-up with the ZF-8HP 8-speed transmission and are thinking of taking your truck into your Dodge dealer for a transmission oil flush, here is an analysis of the costs of this procedure. We hope you are sitting down.
Photo credit: Wikipedia
A few months ago, we ran an article about the outlandish cost of an EcoDiesel engine oil change at Dodge dealerships. But we recently started hearing rumblings about the cost of an ATF flush for Ram 1500 trucks with ZF 8-speed automatic transmissions. So we called a few Dodge dealerships in Canada and the United States to verify. As we learned more about the cost of the ATF change, the price of the motor oil change seemed like a wonderful value!
Ram EcoDiesel Transmission Oil Change Cost
We called a few random Dodge dealers and asked for quotes on a complete ATF oil change for a 2015 Dodge Ram 1500 with the 3.0L EcoDiesel engine. The prices below are for a complete ATF change, replacement oil pan and labor. As you can see, there is a fairly wide range in prices, so the parts and procedure costs may vary at your Dodge dealership.
USA $824.00 to $1105.00 (before taxes)
Canada $1135.00 to $1490.00 (before taxes)
The German-made ZF-8HP75 8-speed transmission is found in several Ram models as well as some Dodge Charger, Challenger, Durango and Jeep Grand Cherokee models. This versatile transmission is even found in some Roll-Royce, Aston Martin, Range Rover and Maserati models.
What Makes This ATF Oil Change So Costly?
The main items billed for this ATF service are 9 (or so) quarts of the Mopar ZF 8&9 Speed ATF, a replacement oil pan (which has an integrated oil filter) and one or two hours of labor. The ATF and transmission pan are priced to the moon, so this is where the bill really skyrockets. The replacement cost of a complete ZF 8-speed transmission is $4000 USD which is relatively modest when one considers to the absurdity of a $1000-plus fluid change.
Note that as these ZF 8-speed transmissions are relatively new in Dodge applications, very few Dodge dealers have actually performed an oil change on them. More often than not, service advisors will offer their “$159.00 ATF Flush Special” when you request an ATF change for these trucks. Once you ask them to check on the cost of the ZF 8&9 Speed oil and the pan/filter, they quickly learn that this is no ordinary ATF flush.
Price of Mopar ZF 8&9 Speed ATF
USA- $43.25 to $48.87 per quart (946ml)
Canada- $58.40 to $70.00 per quart (946ml)
Your eyes aren’t deceiving you; Mopar ZF 8&9 Speed ATF costs almost $50 per quart in the US and upwards of $70 per quart in Canada. For a complete fluid change, 9 quarts will be required and possibly one or two extra for the flushing proposes. Why is this ATF so expensive? Who knows? There are top-flight full synthetic substitutes (we offer a suggestion below) that meet the ZF 8&9-Speed spec and are available for a fraction of what Dodge dealers charge for this oil.
Mopar ZF 8&9 Speed ATF is a full synthetic oil made by Shell and is also marketed as ZF Lifeguard 8. The industry spec for this oil is Shell “M-L12108”. Shell designed and manufactures this ATF for the OEM’s but does not market an M-L12108 compatible fluid under the Shell brand. This fluid has a low viscosity to minimize friction for maximum fuel economy. The factory-fill ZF fluid has a translucent, slightly green appearance with an additive that helps technicians detect leaks under UV light.
Price Of Mopar ZF Oil Pan (Part # 68225344AA)
USA- $335.00 To $378.55
Canada- $453.00 to $522.00
The Mopar 68225344AA oil pan for ZF transmissions is a plastic unit with a non-removable, non-serviceable oil filter molded into it. Therefore, the pan has to be replaced when a complete oil change service is performed. The filter itself has a synthetic media, while the pan also has strategically placed magnets to gather metal filings. Also included with this kit is a gasket, replacement pan bolts and a replacement oil fill plug. While this plastic oil pan is reasonably well-designed, its finest attribute is its ability to completely empty your wallet.
About The ZF-8HP75 8-Speed Transmission
The ZF 8HP transmission series was introduced in 2008 to great fanfare and has proven to be durable, efficient and a great performer in a very wide variety of applications. The reason that the industry is moving toward 8-speed transmissions (and more gears in some cases) is to improve fuel efficiency. With 8-speeds, the engine can always be in an optimum RPM range. ZF 8HP transmission gear shifts take place in milliseconds and can shift from 8th gear directly to 2nd when the situation warrants.
These transmissions do not have a dipstick or top fill port of any sort. Oil is added through a plug on the lower side of the transmission housing. There is much confusion at Dodge dealerships about the proper ATF change interval for these ZF transmissions. On one hand, they are actually marketed as “fill for life” implying that the oil never needs to be changed or checked unless there is a problem. On the other hand, there is a severe service fluid change interval set at 60,000 miles (100,000 kilometres).
Elite ZF 8&9 Speed ATF Replacements
We offer two synthetic automatic transmission fluids which cover the Shell M-L12108 specification for ZF 8&9 speed transmissions. The premium option is the AMSOIL Signature Series Fuel-Efficient Synthetic ATF. This elite ATF is designed for long drain intervals and protects during temperature extremes. We often refer to a tortuous field test AMSOIL conducted using AMSOIL Signature Series Multi-Vehicle Synthetic ATF (the sister product of Signature Series Fuel-Efficient Synthetic ATF) in Las Vegas taxi cabs over 100,000 miles. Signature Series Synthetic ATF is as tough as they make them.
The other AMSOIL product that covers the Shell M-L12108 spec is AMSOIL Signature Series OE Synthetic ATF. This is AMSOIL’s budget-priced synthetic ATF and is designed for OEM drain intervals. As transmission fluid changes are a relatively rare procedure, we would spring the few extra bucks for the ultra-premium Signature Series Fuel-Efficient Synthetic ATF.
