Which gear ratio?

[JoshT]

I found a 8.8" axle, with 3.73 gears in the salvage yard yesterday from a 94 2.3 Ranger. It is complete from brake drum to brake drum, with leaf springs, and swaybar for $250. I am looking to put this into the 84 ranger in my sig which is currently equipped with 3.45 gears in a 7.5" axle. I know that technically the 8.8 is the better axle but that 2.8 is hardly an axle destroyer so even the 7.5 would be fine in that respect. Since I'm building this in to more or less a "street truck" and am more interested in how fast it gets to speed than what the top speed is, which would be the better gear ratio for me?

IIRC the 3.45 gears will give the better gas mileage and top speed for normal driving. Where as the 3.73 gears will give me better acceleration, with a lower top speed (which I can't legally drive at on the street). My thinking is that since I push the acceleration that the 3.73 that is made for the better acceleration would be better and (from what I've read) possibly even give better gas mileage. Am I thinking correctly here?

Another thought is I might decide to put on wider and possibly slightly taller rear tires in the not to distant future, for which the 3.73 will also be better gearing that the 3.45. Please correct me if I'm wrong here.

 

[metalmacguyver]

Yes you want the 3.73s.

3.73 is the abbreviated version of the gear ratio, 3.73:1, which is just a measure of how much mechanical advantage or leverage the engine has over the tires. More leverage, faster acceleration.

 

[Beanmachine7000]

Are you sure it's an 8.8"? I thought they only put that behind the 4.0, and only the 28 spline version at that... You said it was from a 2.3 truck... I've got a 7.5" with a 3.73 Trac-Loc that works if ya want it... If I were you I'd find an Explorer to get it from... 3.73 is common in them and you know it's going to be the 31 spline 8.8"...

 

[JoshT]

Yes I'm sure it's an 8.8 I did read the axle tag. I also know that it's 28 spline, not every set up requires the added strength of the 31 spline. An explorer axle would be great but I don't have the need for the 31 spline. I also don't have time, space, or equiptment available to make the necessary mods to it. Half the reason for getting this was for the rear swaybar being fully intact, no issues there with being able to find proper bushings, and the spring packs are in much better shape. The final reason for the upgrade is cosmetic, I want to move the rear wheels out about an inch each side, and will not use spacers to do it.

 

[JoshT]

Couple more questions.

Would I need to do anything to the drive shaft to make this swap work? If I'm reading right I would have to change the flange where it bolts to the axle. Would I have to change the length?

Am I reading right that the 7.5 and 8.8 axle brake components can be swapped. So if my 7.5 had the bigger brakes, or if they were the same size but the ones on the 7.5 were newer I could just swap them over? I think my 7.5 has 10" brakes, I do know they are fairly new.


On other note

But at the moment I've been derailed by a set of 3" drop I-beams. I also found the correct size bushings for the sway bar components I have. I pulled a 1" rear bar from a BII to install on my truck, I was going to install new poly bushings. The set I ordered for the year model BII (can't remember year now) it came from the axle mount bushings were way to tall and narrow. I got on the Energy Suspension website and looked up the dimensions on the bushing I got from the BII, cross referenced it on summit and they had it listed as being for a full size truck or van. So I'll probably just order the $24 bushing set and hold off on the axle swap till I get the equipment to set up an explorer axle. The benefit of the explorer axle being that if I ever get a V8 it'll handle the power with a simple gear swap, which if I ever get a V8 it'll probably be from an Explorer so I'll have the axle as well.

Beanmachine7000, I might just take you up on that offer of the 7.5 with 3.73 and trac loc. If I do I'll either have to meet you in between or wait until the TRS 10-Year Anniversary, which would probably be better for both of us.

 

[Mac]

I'd sure go for the 3.73. I had a stock '98' with the 2.5 and 3.45 gears and it sucked at interstate speeds with any kind of load or head wind. Able to cruse at two grand but think the motor's only putting out about 70-90 hp at that rpm, that's about what it takes just to move the truck thru the air at that speed.
Even a 4.10 might give you better mileage and a whole lot of better acceleration.
Dave

 

[Beanmachine7000]

Couple more questions.

Would I need to do anything to the drive shaft to make this swap work? If I'm reading right I would have to change the flange where it bolts to the axle. Would I have to change the length?

Am I reading right that the 7.5 and 8.8 axle brake components can be swapped. So if my 7.5 had the bigger brakes, or if they were the same size but the ones on the 7.5 were newer I could just swap them over? I think my 7.5 has 10" brakes, I do know they are fairly new.


On other note

But at the moment I've been derailed by a set of 3" drop I-beams. I also found the correct size bushings for the sway bar components I have. I pulled a 1" rear bar from a BII to install on my truck, I was going to install new poly bushings. The set I ordered for the year model BII (can't remember year now) it came from the axle mount bushings were way to tall and narrow. I got on the Energy Suspension website and looked up the dimensions on the bushing I got from the BII, cross referenced it on summit and they had it listed as being for a full size truck or van. So I'll probably just order the $24 bushing set and hold off on the axle swap till I get the equipment to set up an explorer axle. The benefit of the explorer axle being that if I ever get a V8 it'll handle the power with a simple gear swap, which if I ever get a V8 it'll probably be from an Explorer so I'll have the axle as well.

Beanmachine7000, I might just take you up on that offer of the 7.5 with 3.73 and trac loc. If I do I'll either have to meet you in between or wait until the TRS 10-Year Anniversary, which would probably be better for both of us.

I will (hopefully) be at the 10 year, so if ya want it I'll take it out for ya and set it aside...

 

[JoshT]

Yeah if you don't need it and don't mind I would appreciate it. If I happen to be up in that area before then I'll let you know.

Thanks,
-Josh