Ford 4.11 37/9 Ring and Pinion and True Trac Question

[fordguy]

Always thought the ring and pinion would be 41 and 10, but this is an original ford (stamped ford on the ring gear) and it is 37 tooth ring and 9 tooth pinion. Assuming that is an open differential? Also what oil do i use in the true trac, need to put oil in the dana 44, it has a brand new true trac.

 

[bax]

Yes looks like an open carrier. the eaton tru track does not have clutch disks in it. It will use regular gear oil. No limited slip oil required.

 

[Broncobowsher]

37/9=4.11 Ford's idea of 4.10 gearing.
Just like the 4.88 gears are really 4.86 or 4.89
The front can be 4.10 or 4.09
The 3.50 gear option is really a mix of 3.50 and 3.54

4WD is part time and to be used on slippery surfaces. Tires have a good bit of give in them.

 

[hammer189]

I put Volvoline high performance 80W-90 gear oil in mine. It's one of the few gear oils without additives. Look at the Truetrac info/directions. They are pretty specific about which oil to use.
Bought it at autozone.

 

[Timmy390]

37/9=4.11 Ford's idea of 4.10 gearing.
Just like the 4.88 gears are really 4.86 or 4.89
The front can be 4.10 or 4.09
The 3.50 gear option is really a mix of 3.50 and 3.54

4WD is part time and to be used on slippery surfaces. Tires have a good bit of give in them.

Yup I have 4.11's in rear and 4.09's in front......

As to the oil for a TrueTrac I run standard 80-90 in mine. 2 plus years no issues.....

Tim

 

[sykanr0ng]

In recent years Eaton has relaxed about synthetic lubes, they realize the Truetrac is not the only component in the axle and the other manufacturers have requirements too.

The main thing is to avoid friction modifiers meant for clutch type limited slip.

 

[Nothing Special]

However the TrueTrac does rely on friction between the gears to work correctly, so anything that reduces the coefficient of friction (like synthetic lubes) will reduce the effectiveness of the TrueTrac. It won't damage it, but you won't get the full intended torque gain.

 

[fordguy]

thanks for the tips. i am running 4r70w and wanted to make sure the rear end was a 4.11. I bought it as a 4.11 from previous owner. I built the dana 44 with 4.11s before i decided to go overdrive. i am going to run what i have and see what happens as far as overdrive and rpms.

 

[Rustytruck]

Make sure you follow good break in procedures and change the oil again after breakin.