Re-Gearing

Robert_1967 · Nov 26, 2010

I have a 89 BII, I haven't checked what gears are in it, but it has the Auto Trans from a 94 Explorer in it, What would be a better gear for Highway use??

My little BII calls for 205/75/15's and that is what it has, but on the interstate at 75, I'm turning a little around 3k RPM's, and I want to lower that, I know I can get 235/75/15's on the BII, and that is what the Explorer that I got the trans out of called for, but if I have to change gears, what would be a nice highway gear ???

also my speedo is only about 3 miles to fast, I had it checked by one of Tennessee finest with his radar, and then his speedo

Thanks

Robert

BRUTUS_T_HOG · Nov 26, 2010

3.45 is good for me. not great for towing, but not BAD either. i'd say its the perfect mix of highway manners and power.

i have 195/70/14's

adsm08 · Nov 26, 2010

I'm running 215/75R15s with 3.45 gears and a 4.0 manual trans. I'm pulling about 3K at 75MPH too. That is pretty good if you ask me.

3.45 gears were common in the early trucks, but yours being an 89 it is about just as likely to have 3.73s. Honestly, with my 3.45s and my higher 4.0 gears I'm still pretty happy with how the truck drives on the highway and how it tows. Especially for having a used and abused 200K mile 2.9 in it.

Robert_1967 · Nov 26, 2010

My wife's car has a 3.1 v6 and at 75, it is only turning 2300, and get's 30mpg on the interstate, I would like to drop my RPM's down about that far when it hits OD, I was looking for a divorce OD like I had in my Kenworth, but I can't find anyone who makes them for small trucks/BII's

To me it just sounds like that little 2.9 is turning too hard at 3k.

adsm08, it sounds like we both have the same set up, 2.9 with a 4.0 auto tranny.

Robert

adsm08 · Nov 26, 2010

Robert_1967 said:
adsm08, it sounds like we both have the same set up, 2.9 with a 4.0 auto tranny.

Robert

Difference being that the M5OD has different gears for the 2.9 and 4.0 versions. The A4LD didn't.

Also, you wife's 3.1L (presumed V6). That makes that a Chevy, probably a Malibu or Impala, thinking at leas 09+, more likely 05+, correct?

Those are FAR more aerodynamic and much lighter than you 89 B2. To get your 75MPH RPM down to 2300 you will need something in the neighborhood of 3.27 gears backed with 31 or 33 inch tires. You won't like that too far below 75.

EDIT: Ran some numbers through a calculator. 3.45s and 27" tires should net you about 2300 RPM and 71.4 MPH.

So my tires and rear end plus your OD gear should get you 2300 at 71.

Robert_1967 · Nov 26, 2010

The wife's car is a 96 Chevy Lunamia (<-spelled wrong).

she use to be a Ford fan till she bought this car, now she is a Chevy fan, that is till she can get a New VW Beetle.

3.27 would be doable when I can trade for another Explorer, I just took the engine and trans out of a 92 Explorer to put in My 88 Ranger, and the rear is the 8.8 with a open 3.27

So when I get my Truck finished, I'll look for me another Explorer, and that should help out.

Robert

adsm08 · Nov 26, 2010

How far is White Pine from Nashville?

I have a set of 3.27s in a Ranger axle. I can pop the pins out, grab the center chunk, and send it down with my sister in January.

Robert_1967 · Nov 26, 2010

I was just in Nashville at Vanderbilt hospital, it's some where around 200 miles.

Robert

adsm08 · Nov 26, 2010

Hmm. that's a bit out of the way.

Robert_1967 · Nov 26, 2010

That's OK, right now I couldn't afford to buy new chunks any ways.

I really can't do any thing to the BII till I get my Ranger fixed, but I was just wondering what would be a good gear to try and run in the diffs, a lot of times I can't figure out the axle ratios, like is a 4.10 a taller or lower gear then 3.27 ?? and is a 3.43 a lower gear???

see, what I mean.

Robert

adsm08 · Nov 26, 2010

The numerically higher a gear is the lower (shorter) the actual ratio.

Say you have one truck with 3.27s and one with 5.13s, all else the same. The 3.27 truck will have slower acceleration but a higher top speed and will suck for towing. The 5.13 truck will have awesome off the line power and pull, will be a great tow rig, but will probably top out around 35 MPH with stock tires.

As for "buying" my 3.27 chunk, I can't seem to give this stupid thing away. The only reason I wouldn't give you the whole axle is because I don't think it will fit in her car. I'm also not sure that little VW 2.0 turbo will pull that thing the whole way down there.

Hahnsb2 · Nov 26, 2010

I wouldn't wish 3.27s on my worst enemy.

Leave it alone, it's right where it needs to be.

voodoochylde · Nov 27, 2010

I've got an 86 BII with a 2.9L, M5OD from a 92 explorer, 3.73 open gears front and rear, and I'm running 235-70-R15 tires. I do around 2300 to 2400 at 70mph on the interstate.

Blasted thing's got no power but I think the motor just sucks. Preparing for a 4.0 swap and D35 and 8.8 this spring/summer

84bluebronco2 · Nov 27, 2010

I have a 4.0 94 explorer with M5OD and 3.27s. 3.27's are obnoxious for hills and towing, but on the highway with 235/75R15's I do 2250 at 70mph.

adsm08 · Nov 27, 2010

I went to school with the guy I bought my 3.27 axles from. He had a 4.0, 5 speed, and 35s on those axles. It moved them, but it wasn't pretty.

Re-Gearing

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