found a great purchase canidate. its a stock 89 4x4 single cab 5 spd but has the 4:10 gear ratio. has anyone calculated the actual mpg difference between the 2 ratios? maybe i should ask what the rpms are for 65 mph or 70? i think the truck has stock or close tires. maybe the 235/85r16's. thanks

 

I believe it is about the same as the guys are getting with the non od 727 and 3.07s... high teens.

 

I was told when I bought my 93 it has 3.73's. I figured the mpg to be about 17 on the highway over a 130 mile trip. But the truck is done at about 80 and its sounds like it is rapped up tight. I usually cruise it about 65 or 70. It is also running a little bigger tire to try to lower the rpm's.


And while we are talking about this why are the majority of you guys running such high gears. I see some people running 3.05's and such. Are most of you running 2wds or just going to the high gears for speed?

 

I have 4:10s for my w250/w200 crew but with triple OD it will be ok on the freeway empty.

 

I think timing, fuel system condition, and driving style will affect your MPGs more than gears, unless you HAVE to go 70+mph. I had a 2wd dually that got 21-23mpg with 4.10s IF I went 63-68; over 70, and it was more like 18-19. Current truck has gotten 20 a time or two, but it's nothing you can depend on.

 

it depends on how fast your driving, if you drive 55-60 mph it would be close to the same as 3:54s at 65-70

 

I actually did a 4:10 to 3:54 and noticed maybe a 1 to 2 mpg gain cruising at highway speed. During the summer i was able to get 22mpg a few times running 70 on the interstate. Its a lot better on the interstate cause it isnt turning near as hard. Turns about 2100 at 70. As far as towing it stills tows great. Occasionally you have to shift to 4th when you might not of had to before. I've been very happy with the swap.

 

someone must have put the 3.73's in if thats what they told you becuase they werent offered. 3.54 and 4.10 was it

3.07 gears were the only gear offered in 89-91 3 speed auto trucks because they didnt have overdrive. Some guys put 3.07's in there O/D auto or 5 speed trucks to simply get better highway mileage.

 

I got around 17-18 mixed with a 93 5spd 4.10...... But on a trip to MN I got 20-21 doing 70 on the highway. I actually saw the odometer turn over 525 miles on the tank when the low fuel light came on! My light turned on when there was about 3-4 gallons left in the tank.

 

I went from 4:10s to 3:54s I noticed around 2 mpg gain on city/highway driving. I average 19 now. Before on the interstate cruise was hold it to the floor.