The dealer tells me that he does not recommend a fluid flush on my 40,000 mile XJ8. He actually believes th efluid is good forever..must be the party line but it is not true.He must be nuts to turn down an easy $700 which is what he wanted for it. I have been doing some research and the ZF website for their own remanufactured trannies says the fluid in the 6hp26is great andgood for 62,000 miles (100,000K). This would tell me that it is a very good fluid to go that long but it definitely needs to be flushedbefore then. The dealer wants $100/qt for the Shell M1375.4 which only they sell, Castrol claims their $4 all-vehicle fluid will work and $4 Motorcraft Mercon SP also claims it will work in the 6HP26. By the time my car is nearing 60K miles, I will flush it. Maybe by then, the fluid issue will be clearer. It's hard to find out much now when the dealers don't want to do it and tranny fluid change is not even on the Jag maintenance chart. Since normal 4 speed ZF trannies like fluid changes at 25-35K miles, going twice as long with the fancy synthetic fluid seems about right to me, but I'm just guessing.

 

stick with the proper jag fluid.. that trani is way to expensive to be installing incorrect fluid.. saving a couple bucks now can cost you thousands and i mean thousands..

 

This is the e-mail I from from ZF when I asked about the transmission fluid. Emphasis mine.

Best Regards / Mit freundlichen Grüßen

Dear sir, I have included a lubricant list to help you determin the correct fluid for your application. You did not indicate the vehicle make or model. As you review the list please notice audi does require the Lifgueard Fluid 6 plus. What ever type of vehicle you have the dealer also offers the equivelant fluid to our Lifeguard oils. Currentl there are no aftermarket oils that meet the ZF 6 speed fluid specification. Using the wrong fluid may result in slipping or firm shifts due to transmission controler attempting to over componsate for incorrect friction capabilities of the wrong fluid. As well as possible torque convrter chatter again from the friction modifiers being incorrect for the modulated lock up function of the torque converter.

Steve Jaffe
Regional Service Manager Passenger Car/ Light Truck
ZF Sales and Service North America, LLC
777 Hickory Hill Drive
Vernon Hills, IL 60061
Phone XXX-XXX-XXXX
xxxxxx.xxxx@ZF.com

PS: I could not submit the reference PDF that he sent.

 

i think everyone should read this.

 

So does Zed F list more than one ATF (Shell 1375.4)?

 

The fluid name ZF uses is LifeGuardFluid6, they don't mention Shell in the list for ZF 6 speed automatic. There are 3 different packages you can order, 1 liter, 20 liter and 209 liter.

There is also LifeGuard6FluidPlus, which is used in the similar transmission for the Audi A8 with W12 engine and Audi Q7. It was also mentioned in one of Jag TSBs as addon.

ZF part numbers for the fluid:
S671 090 252 Oil LifeGuardFluid6 (209 liter drum)
S671 090 253 Oil LifeGuardFluid6 (20 liter canister)
S671 090 255 Oil LifeGuardFluid6 (1liter bottle)

S671 090 280 Oil LifeGuardFluid6+ (209 liter drum)
S671 090 281 Oil LifeGuardFluid6+ (20 liter canister)

 

Another response from ZF about the maintenance schedule:

Dear Sir, The 6HP transmission is considered to have a lifetime fill and never require service. This is difficult for many maintenance minded owners who feel they must provide regular service. I have spoken too many concerning this issue and all have a limit as to how long they can tolerate the nagging need to service the transmission. Some insist on 60K other start to loose sleep at 100K. Once out of the vehicle manufactures warranty servicing the transmission is a personal decision, just be sure to put the correct ZF fluid and filter.


Best Regards / Mit freundlichen Grüßen Steve Jaffe
Regional Service Manager
Passenger Car/ Light Truck
ZF Sales and Service North America, LLC
777 Hickory Hill Drive
Vernon Hills, IL 60061
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