Preparing to do a PTU flush

[wlepse]

I have been reading through the threads and am planning to do my first flush just prior to vacation. Hoping the long trip from NJ to SC will mix things up in there and help clean it up so when I return I can flush it again and be pretty close to clean fluid. Anyway, I have see the posts about the zip tie level check and I think I am all set with one exception. I see the PTU uses 75W140, but many of the gear oils I have seen listed also mention a friction modifier. I am not positive but I didn't think Ford added that to the PTU, I seem to remember seeing it being added to the RDU but that uses a different oil I believe.

 

So to those that have done this; what oil did you use and did you add friction modifiers?

[carguy75]

I have been reading through the threads and am planning to do my first flush just prior to vacation. Hoping the long trip from NJ to SC will mix things up in there and help clean it up so when I return I can flush it again and be pretty close to clean fluid. Anyway, I have see the posts about the zip tie level check and I think I am all set with one exception. I see the PTU uses 75W140, but many of the gear oils I have seen listed also mention a friction modifier. I am not positive but I didn't think Ford added that to the PTU, I seem to remember seeing it being added to the RDU but that uses a different oil I believe.

 

So to those that have done this; what oil did you use and did you add friction modifiers?

From my understanding most aftermarket gear oil contain friction-modifiers now.

 

However, some locking-diffs are very specific about if or what type of friction modifiers are used or not depending if they have clutches(could cause the clutch to slip if the wrong type is used)..

 

For the clutch-less gear set-up in out PTU units the friction modifiers added to gear oils are not a problem, hell it may even help our PTU last longer due to reduced friction and heat in the gear mechanism.

 

I will be using Royal Purple full synthetic 75w-140 gear oil in my PTU.

 

I will do a suction-and-fill every 30K miles when I do my transmission fluid so that I will keep fresh oil in my PTU since I can not drain it completely.

 

I figure if I change the PTU fluid every 30k miles the fluid will never wear down enough to do any damage to the gears or turn to sludge,

 

It may be over-kill to some, but oil is cheap while PTU/transmissions are not.

Edited August 1, 2015 by carguy75

[wlepse]

Thanks for the feedback. I also found a few references to the PTU requiring GL-5, so make sure the gear oil you choose meets that. By the way what are you putting in the tranny? Doing anything for the RDU? The fluids are so cheap I think it is worth it to do fairly frequently. I am thinking about doing the PTU yearly which is basically 20k. Just thinking it is easier to put on my calendar for a yearly thing than rely on the wife reminding me when she has gone x miles.

[carguy75]

Thanks for the feedback. I also found a few references to the PTU requiring GL-5, so make sure the gear oil you choose meets that. By the way what are you putting in the tranny? Doing anything for the RDU? The fluids are so cheap I think it is worth it to do fairly frequently. I am thinking about doing the PTU yearly which is basically 20k. Just thinking it is easier to put on my calendar for a yearly thing than rely on the wife reminding me when she has gone x miles.

No problem.

 

I will use only the Ford LV transmission fluid.

 

I have always just use the OEM transmission fluids when i do changes since some cars transmissions are very sensitive to additive levels.

 

While some aftermarket transmission fluids may be better that OEM, they can be too slippery for a specific application and cause slippage.

 

However, in non-clutch applications I will always use the the most slippery spec oil that meets the qualification.

 

RP is a GL-5 spec oil.

 

http://www.royalpurpleconsumer.com/products/max-gear/

 

I changed out my OEM 80w- 90 RDU gear oil for 75w-90 RP gear oil, however the rear diff in our cars are rarely used by the PTU so I will change my gear oil every 60k miles in the RDU.

 

Which would be about 90k miles for my car since I just changed the gear recently at just over 25k miles.

Edited August 1, 2015 by carguy75