I just crawled under my new truck today since it actually wasnt raining... I read something I thought I would never see on a pickup... 273 88 yada yada. Luckily I own an 89 with an engine problem that has a 355 gearset. Am I going to be able to bolt this axle in? I know the 93 has 4wabs and the 89 has just ABS. They are both straight 6's with 5 speeds. thanks for the help!

 

The 3.55 rearend will bolt right up.

 

i dont think that 93 has 4WABS... pretty sure ford didnt do that till the 97's and up

 

Ahh ok, Thats good news. Thanks guys. Seams to tow a couple thousand pounds around pretty well, tried it today.

 

If the truck is 4wd you will need to swap the front gears as well.

 

I am not going to argue, but if you are just using the truck for a DD, why change the gear. That's some good gas mileage.

 

On the highway, yes. In town, no.

 

Does it take that much to get them going?

 

The numerically lower gears will get worse gas mileage around town than the numerically higher gears. It is usually opposite on the highway.

 

Kind of depends on how fast your town is...around leadfoot, flatland Detroit, I can get my M5OD/2.73 '91 into fifth a lot without getting anywhere near a highway (a sustained 50 mph keeps the I6 happy), but generally speaking, you're right, you'd get into OD more around town with a slightly shorter axle ratio, I'd think.

 

The point is that a numerically lower gearing puts more load on the engine when trying to get the truck moving from a stop, because moving the vehicle from the stop requires a lot more force than keeping it moving at higher speed. Around town there are a lot of instances where you need to accelerate from a stop while on the highway there is not.

 

My '89 gets near identical city/highway mileage, due to the 4:10 gears and the overdrive.

I'm consistently using OD when I'm cruising around at 35mph or higher, since at 35 in 4th, my engine is running close to 2k RPM's, and my average city mileage is 8-11 miles per gallon (depending on road conditions, how heavy my foot is, etc...) Winter mileage is 7-8 average due to using the 4x4 a lot, and slightly longer than normal startup times.

At 65mph, in OD, I'm running right around 2500 RPM's, and get around 8-10 miles per gallon, but it drops *significantly* if I go faster than that. At 70mph, I see mileage in the 5-6 range. Needless to say, I don't drive too terribly fast on the highway in this rig.

If I were running the same 3:55 gears my '85 has, I'd see better highway mileage, but probably worse in-town mileage running the big 460 engine. The '85 doesn't have the overdrive, and is a carbureted 351W, but gets around 10-13 city, and 12-14 highway depending on conditions. Were it to have an overdrive transmission, I could probably expect around 15-17 mpg highway.

Gearing *does* make a large difference in mileage, but also in towing/hauling capacity as well. If you only drive highway on the rare occasion, and mostly use it for in-town driving, I see no harm in getting a different gear ratio. I personally like the 3:55's, as I see it as a good balance in low-end power and high-end mileage.

Hope my long-winded post here didn't bore you too much, and was at least marginally helpful.

 

Oh; okay. My bad. Makes sense. I can still do more than 20 miles at a steady 50 to 60 without getting on a highway OR stopping for a light (they're timed) as long as the traffic's not too thick, but I get the more general point. Thanks.

 

Just to clarify, what Skandocious says is right. However, when most guys refer to "lower gearing" in a rig, they are talking numerically LARGER. Lower numbers = higher gear ratio and vice versa.

 

Correct. But for anyone who doesn't know that rule of thumb, specifying that you're speaking of NUMERICALLY higher or lower gears is the fail safe