Need Advice: Which Gears for an 8.8 Rear End?

[Aoresteen]

I need some advice here. I just bought a 1991 8.8" open rear end with 3.08 gears & 10" brakes to swap into my 1990 Super Cab 2WD 2.9L Ranger with auto transmission (A4LD). My Ranger came with 3.45 gears in the 7.5" rear end with 9" brakes.

The 8.8" rear end came out of a 1991 2WD Super Cab with the 4.0L V6.

Next week the rear end will be sandblasted & painted then it's off to the differential shop for a full rebuild.

Originally I was thinking that I would use 3.55 gears as it is close to the original 3.45 gears. 3.45 gears don't seem to be available in 8.8" size.

I will be driving 95% on streets & highways, 5% off-road on gravel/dirt/cow pastures to set up ham radio antennas. On occasion I will also be towing a light flatbed trailer with antennas.

I will also be upgrading to 15" rims and 235/75R15 tires (Goodyear Wranglers Silent Armor are the ones I'm looking at).

The 3.08 gears that I have should give me better gas mileage. I will also get less torque.

No matter what I do I will have to have the speedo re-calibrated.

Given what I plan to do, should I keep the 3.08 gears or swap in 3.55 gears?
The cost of the 3.55 gears (about $135) is irrelevant as the shop will install them during the rebuild at no extra cost.

Thanks!

 

[Angie]

hi, read through this and see if this can shed more light on your questions.

http://www.hotrod.com/how-to/transmission-drivetrain/how-gear-works/

cheers

ps, i would keep the 3:08, all my trucks have been 4.oL 3:08 and i never had any probs. the truck i am building with 302, i built with 91 rear end and new 3:08 gears. hope this helps some how.

 

[gw33gp]

I wouldn't run 3.08 gears with a 2.9L engine unless I was running some short tires. I had an 89 STX Ranger with the 2.9L engine and it came with 3.73 differentials. The tires were about the same size (~29" tall) as what you are considering. I upgraded to 31" tires and they were too tall for the 3.73 gears. I eventually switched to 4.10 gears and it worked much better.

I had a manual transmission and the clutch suffered a lot with too tall gears but the engine also struggled with hills and head winds. With an automatic trans you don't have to worry about the clutch but hills and head winds are going to still be a problem with too tall gears.

The 3.55 gear should work OK with those tires if you are looking to keep the rpm down, especially with 2WD . I ,personally, would go for the 3.73 gears, if they are available in a 8.8, because I like to have more pulling power due to towing and going off-road a lot. It doesn't sound like that is important to you.

 

[scotts90ranger]

I would choose 3.73, it's what most of the RBV's that came with 235's came with from the factory

 

[Aoresteen]

I would choose 3.73, it's what most of the RBV's that came with 235's came with from the factory

Thanks! That's a bit of info that I wasn't aware of. 3.73 are on the list.

 

[Aoresteen]

Thanks for all the feedback. After considering all the info I got, I purchased a set of 3.73 gears today for my 8.8" rear end. Anyone need a 3.08 set cheap ?

 

[Dprocks100]

+1 on the 3.73 gears. My brother had 3.45 in his 91 3.0 2wd with 235/75r15. It was a dog to drive and couldn't get out of its own way. Killed a clutch in 5,000 miles that could have worked for another 15-20,000 miles on his old 205/70r14 tires. Swapped in an axle with 3.73 gears and its night and day difference. Much better to drive up hills and to tow with. You will be a lot happier with them!

 

[adsm08]

I agree on the 3.73s. I popped a 3.73 axle into my truck that came with 3.45s, and it is a big difference for such a small change.

 

[SenorNoob]

3.73s FTW! Although I'm wanting 4.10s now cause I wanna run bigger tires. Too bad a D35 TTB pumpkin is so hard to find with that ratio..