different gear ratios front and rear

[ididieseler]

just bought a 1978 f150 i'm planning on putting a 7.3 in it. the rear is a ford nine inch with a 4.11 detroit locker .....not ideal for a dd. i want to put 3.50 gears in the back and 3.54's in the dana 44 up front. as long as i dont drive in 4wd on pavement i should be fine right?

 

[jasonhughes]

should be fine. ive seen many a vehicle (mostly chrysler products and the last year or two of diamler/chrysler, but im sure they've all done it) come from factory with 4.10 in the rear and 4.11 in the front. you just want to make sure the front has the slightly higher numerical ratio
by no means is it an ideal setup, but itll work

 

[turbo elk]

As long as you don't engage 4 wheel drive.... or are driving in sand or maybe mud...I've driven in sand with 33" tires front and 35" in back no problem, just listen for bad sounds and don't go far.

 

[PwrSmoke]

The difference between 3.54 snf 3.40 is tiny and as pointed out, many companies did that exact mismatch. Ford included. You'll be fine! Ford always had a problem matching the 9-inch ratios to Dana Ratios. The design of the 9-inch required different gear cutting machines and in the day, they couldn't exactly match the ratios (anyone remember hunting and non-hunting 9-inch gearsets)

 

[riotwarrior]

Wont be a problem what so ever, so long as in snow/mud/sand/off road NON pavement environment

Why the gear swap? 4:10 is a great gear for 33-35" tyres and IT keeps your costs down too!

Nothing wrong with a Detroit locker for daily driver either....especially a LB PU wheel base is good for that setup!

JM2CW

Al

 

[chris142]

The early bronco's came with that same gear difference. 9 inch in the back and a d30 in the front. Close enough just don't try 3.73 and 3.07 or something else weird.

 

[GOOSE]

Factory gearing was 4:09 front and 4:11 in the 9"

 

[ididieseler]

going for gas mileage with the 7.3 so i'm gearing it up

 

[PackRat239]

Thats the way every 4 wheel drive ever built was equipped, ratio wise, so dont worry about it.