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bill, chrysler master tech
Category: Chrysler
Satisfied Customers: 1632
Experience:  25 years with chrysler drivability and electrical expert
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I made the mistake of letting Mr.Lube change some fluids in

Customer Question

I made the mistake of letting Mr.Lube change some fluids in my 04 Pacifica. At the time they were having an argument about what fluid was used in the rear PTU. I didn't think much about it until this winter when I noticed the RWD was not working. On the hoist it appeared to be working and if one wheel was locked the Differential would spin the other. Under load however it would not transfer enough power to assist in movement. I remembered the day at Mr. Lube and their inability to determine if it was ATF or 80-90 fluid that it required so I thought I better Check the Fluid. Sure enough when I drained it it came out like jelly and was red mixed with the smell of 75-90. It was obvious they had put in ATF and not 75-90. I drained it twice now and replaced it with the proper 75-90 but it must be plugged up as it still has no power. I am not familiar with the inside of the unit but assume it has liquid clutches and they are likely plugged. Any suggestions as to how to clean it out or do you think the ATF they put in ruined the unit?
Submitted: 1 year ago.
Category: Chrysler
Expert:  bill replied 1 year ago.

the big problem with the rear PTU is it has NO service parts available and if it refuses to operate it must be replaced, you should have a claim against Mr. Lube as long as you still have the receipt with the type of fluid installed on it, and like our favorite in Connecticut "jiffy lube" the company should have a insurance company that deals with their screw ups

Customer: replied 1 year ago.
Thanks Bill, I kind of suspected that it would need replacement. Just thought maybe there was some way of cleaning it out before looking for a used one. As I said the combination of the two fluids resulted in a jelly like substance. Not many Pacifica's around here and all the ones that I found are only Front wheel drive. Might go back after Mr. Lube as I think on the receipt it says that they used ATF.
Expert:  bill replied 1 year ago.

go for them first I can provide the specs for the needed fluids for you if you want or they may be in the owners manual, the rear differential module has 2 fluid sumps and takes BOTH ATF+4 trans fluid in one sump and 75W90 in the other the 2 must never mix or damage will result here is a description of how the rear module works.

one would hope the lube tech noticed the difference between the 2 as they are definitely very different in color odor and viscosity, but that may be why they are still lube techs


The rear driveline module assembly (Driveline Module Section) consists of three main components:

  • Bi-Directional Overrunning Clutch (BOC)
  • Viscous Coupling
  • Differential Assembly

The viscous coupling and bi-directional overrunning clutch are contained within an overrunning clutch housing, which fastens to the differential assembly. The overrunning clutch housing and differential assembly have unique fluid sumps, each requiring their own type and capacity of fluid. The overrunning clutch housing requires Mopar® ATF+4. The differential assembly requires Mopar® 75W-90 Gear and Axle Lubricant.

Driveline module service is limited to the following components:

  • Differential Assembly (serviced only as assembly)
  • Viscous Coupling
  • Bi-Directional Overrunning Clutch (BOC)
  • Overrunning Clutch Housing
  • Seals (Input Shaft, Output Shaft, Overrunning Clutch Housing O-rings)
  • Input Flange/Shield
  • Vents
  • Fasteners