**Although the Royal Purple gear oil contains friction modifier, we highly recommend including the Ford Racing friction modifier along with the gear oil when refilling your rear end.**
Due to Hazmat regulations, lubricants/fluids cannot be shipped to APO/FPO addresses.
Check out our YouTube channel for even more tech tips, installation videos, how-tos, and more. The best place to go for anything Mustang related!
you can use these gears in the IRS and should not affect wheel hop. The soft IRS bushings is the reason for the wheel hop. Check out our site for IRS bushings.
Answered by BRYAN M. from TROY | Comment 2 0
The bearings are different. here ya go.
Answered by BRYAN M. from TROY | Comment 0 0
We would need to know what rear tire size you have to more accurately choose what gear you would need. For your 91 with an auto transmission it would have come from the factory with a 8 tooth drive gear. You can enter your information here http://www.latemodelrestoration.com/products/Mustang-Speedometer-Gear-Calculator and it will tell you what gear you will need.
Answered by Nathan A. from Waco | Comment 0 0
I installed 3.73's in my 1992 5.0 with minor bolt ons and an automatic and was very happy, but I wish I would have went with 4.10s instead. If you plan on keeping the car mostly stock w/the automatic, I'd say 4.10s.
Answered by Mathew H. from Troy | Comment 0 0
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