i got a set of 77.5 f250 axles. i spun the tire and counted the pinion rotation on the back 60 and it was almost 2 times for one tire rotation. am i missing something or was there a gear ratio that was that high on those? the front was a hp 44. those brakes are seized up so i haven't spun the tires yet. any help with gearing options for these things?

i got a set of 77.5 f250 axles. i spun the tire and counted the pinion rotation on the back 60 and it was almost 2 times for one tire rotation. am i missing something or was there a gear ratio that was that high on those? the front was a hp 44. those brakes are seized up so i haven't spun the tires yet. any help with gearing options for these things?

Pinion will spin half the gear ratio per wheel revolution on an open dif, ie: 2.05 pinion turns = 4.10 gears.

Sounds like you have 3.73s.

thanks for the info. if i gear lower do i need a new carrier?

thanks for the info. if i gear lower do i need a new carrier?

D44 carrier break is at 3.73, so 3.73 and down for series 3 carrier, 4.09 and up for series 4 carrier.

You'll need to confirm exactly what gears you have, 3.73 would be very uncommon in that year 4X4, if it was even available then. I've seen tons of 2wds with 3.73s, it was probably the most common in that era.

The steel tags on the cover bolts will have the ratio on them, if they are missing pull a cover and count the teeth of the ring and pinion. Divide the number of ring gear teeth by the number of pinion teeth.

almost two turns would be 3.55s the ford 4x4 only came with 3.55 or 4.10 in those years

almost two turns would be 3.55s the ford 4x4 only came with 3.55 or 4.10 in those years

That sounds right.

3.54 in the Dana axles. 3.55 is 8.8 and Sterling. The only gear options on the F-250 that year were 4.10 and 3.54. The F-150 could have had 3.73 and also possibly a 3.00. I'll never understand why they never offered a 3.73 in 3/4 ton 4 x 4 in the 70's. It seems like the perfect ratio for a truck. I guess they needed the 4.10's for power, and needed the 3.54's to offset the fuel economy for the model to meet the EPA's regs?

incredible. were there any types of limited slips offered back then? and the front has flat tops on it. driver side has an arm attached to it. i read through mr n. but still get kinda confused. can i use these for high clearance? i looked at sky manufacturing (http://www.sky-manufacturing.com/new/)and they seem to have decent prices for milling and drilling. 8 lug

incredible. were there any types of limited slips offered back then? and the front has flat tops on it. driver side has an arm attached to it. i read through mr n. but still get kinda confused. can i use these for high clearance? i looked at sky manufacturing (http://www.sky-manufacturing.com/new/)and they seem to have decent prices for milling and drilling. 8 lug

TracLoc was available in the front, maybe PowerLoc too but I've never seen one that I thought was from the factory. For sure they were both available in a rear d60. Bookmark Mr.Ns site, you'll need to visit it more, it's pretty damn handy. (Happy Freakin Easter Mr. N!!).


Yeah, these are the good knuckles. The drivers side is already milled/drilled tapped but that is unecessary for crossover steering but it would be used for high steer cuz you'd have double arms. I like SKY, they d&t'd a knuckle for me, did a good job, fast.

that's good to know. i have 3 sets of those knuckles. might just bight the bullet and send all of them out. thanks for the info.