lukemahonyfx4

Just picked up my rear axle (9.75) and front diff (8.8 IFS) from a local driveline shop. They are highly recommended and have been around for years, so I think I can trust them. It had 3.73 in them, moved up to 4.56 with my 35s. The driveline shop told me to use regular gear oil instead of synthetic oil for the break in period (first 500ish miles), then change the oil to synthetic. I have never heard of this, he said they break in much better with conventional oil. I will still use the 4oz of Ford Friction Modifier in the rear, as it is a limited slip. I also bought a new high capacity Mag-Hytech rear diff cover that says it will hold 5 quarts of oil (instead of the stock 2.5-3 qts).. How much oil does the front 8.8 IFS diff take, 2 quarts? And if I am correct Ford recommends 75W90 in the front, and 75W140 in the rear. They were both complete rebuilds, including new ring, pinion, pinion bearings, carrier bearings, outer axle bearings (in the rear), ring bolts, all new races, and seals. What are your guys' thoughts? By the way it cost me $1400 total ($620 for front, $780 for the rear).

gDMJoe

The front dif' lube capacity (and recommendation) will be specified in the owner's manual.

(owner's manual) Don't have one -OR- would like a digital, searchable desktop document?.

HINT/TIP: Put your vehicle information in your sig' -OR- provide it in your posting(s).

*Telepathic or Carnac we're not.
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