3.31 Ratio ring gear and oil coolers

[Rutim]

I've been looking through Tasca Parts for a PTU Cooler setup. I did come across the PTU with cooler provision. Also, I found engine oil coolers in junkyard and the hoses at Tasca required for the swap. Now, when searching Tasca for some of these parts I ran across a 3.16 ring gear, but also a 3.31 ring gear for the 6F55. When I did a gear swap in my MTX75 Focus trans I replaced both the ring gear and the driving gear. I'm looking to see if a driving gear is required in the 6F55. Any help would be much appreciated. Yeah, 1st post!

 

[802SHO]

Yeah 3.16 is the performance package and PI cars. 3.31 would work you’d need the matching pinion gear set. You should try searching 3.31 ring and pinion gear sets and you might find a used set. Like this

 

[J persons]

Is there a 3.31 R&P for the rear diff?

 

[802SHO]

Don’t think it’s needed I believe the PTU and RDU equal each other out

 

[Texas Marauder]

Don’t think it’s needed I believe the PTU and RDU equal each other out

Correct

 

[Jordan_R]

Not correct. All the RDU gears are the same 2.93 ratio and the coupler system just slips and engages repetitively. Regardless of final drive in the transmission. There is no 3.31 for the 6F55

 

[Texas Marauder]

Not correct. All the RDU gears are the same 2.93 ratio and the coupler system just slips and engages repetitively. Regardless of final drive in the transmission. There is no 3.31 for the 6F55

I think what he is saying is that the PTU and RDU are the same ratio. Both are 2.93. Otherwise there would be binding in the rear driveline. Yes, I know it is a slipped clutch engagement with varying percentage of engagement. The final drive of the transmission is something completely different. IMO, it is not feasible, nor likely possible, to try to change any of the gear ratios.

 

[Jordan_R]

I think what he is saying is that the PTU and RDU are the same ratio. Both are 2.93. Otherwise there would be binding in the rear driveline. Yes, I know it is a slipped clutch engagement with varying percentage of engagement. The final drive of the transmission is something completely different. IMO, it is not feasible, nor likely possible, to try to change any of the gear ratios.

It doesn't bind because it doesn't engage. The coupler system just let's it give. As far as we know until someone counts the teeth in the PTU we believe it's 1:1 because out of all of the ratios in the 6f55 (2.77, 3.16, 3.39 and 3.69) they all use the same 2.93 final drive RDU. Swapping the final drive is possible and has been done, but is it worth it? Time will tell.

 

[802SHO]

Here’s the ptu gears

 

[Jordan_R]

Here’s the ptu gears View attachment 92329View attachment 92330

You're right on this it is 2.93

 

[Jordan_R]

I was wrong about this. Sounds like everything is final drive based regardless as they do properly cancel out.

 

[802SHO]

I was wrong about this. Sounds like everything is final drive based regardless as they do properly cancel out.

I took that pic like a couple years ago I think John wanted to know. Just remembered I had it.

 

[Jordan_R]

There is some more context here that I'd like to add that I think is beneficial to the community. The PTU and RDU effectively negate themselves into the assumed 1:1 ratio. Final drive doesn't matter because it's based off wheel rotations and not the transmission gearing itself. Front wheels rotate once and the wheels will effectively rotate once. That being said. You can swap the final drive in the transmission, albeit, not beneficial in a mild application. 2.77 or 3.16 the vehicle comes with is plenty enough gearing for anything the stock location turbos can put out, heck, even maybe the big boy stuff. Final drive is plug and play though for those that have thought it was impossible all these years.

 

[Highway Star]

For a 2015 Ford Taurus, the rear differential ratio is typically 3.39; however, this can vary slightly depending on the trim level, with the high-performance SHO model having a slightly

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Key points about the 2015 Taurus rear differential ratio:

• Standard ratio: Most 2015 Taurus models have a rear differential ratio of 3.39.
  
  
  
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• SHO model: The Taurus SHO typically has a rear differential ratio of 2.77, designed for better acceleration.
  
  

 

[Jordan_R]

For a 2015 Ford Taurus, the rear differential ratio is typically 3.39; however, this can vary slightly depending on the trim level, with the high-performance SHO model having a slightly

Key points about the 2015 Taurus rear differential ratio:

• Standard ratio: Most 2015 Taurus models have a rear differential ratio of 3.39.
  
  
  • 
    
    
    
    
    
  • 
    
    
    
    
    
  • 
    
    
    
• SHO model: The Taurus SHO typically has a rear differential ratio of 2.77, designed for better acceleration.
  

The final drive on NA Taurus is 3.39. RDU on all is 2.92

 

[Highway Star]

The final drive on NA Taurus is 3.39. RDU on all is 2.92

The point being 3:39 ring and pinions are available. 3.7 AWD had 3:39's Std.

 

[Jordan_R]

The point being 3:39 ring and pinions are available. 3.7 AWD had 3:39's Std.

Yes, for the front differential inside the transmission.

 

[Texas Marauder]

The point being 3:39 ring and pinions are available. 3.7 AWD had 3:39's Std.

More accurately named final drive ratio, which is internal to the transmission.

 

[Rutim]

Yes, for the front differential inside the transmission.

And once the power is put through the transaxle (front differential) the drive axles and RDU are driven at the same speed. "Sounds like everything is final drive based regardless as they do properly cancel out." per Jordan_R