Should I change the gear ratio

[junkyardjeff]

My now 2wd 1988 bronco has 3.55 gears and was thinking of going to something around 3.25 since I think it needs pinion bearings due to a excessive clunk,I still have 31-10.5 tires on the rear and will have a similar size when they wear out. It presently has a 302 but considering a 351 swap but might be years out,I am worried about lugging the 302 when its in overdrive so should I keep the same ratio and repair the clunk or go with a slightly taller gear.

[UGLY OLDS]

Jeff ....  
I would be careful changing gears ... My '89 GMC has a 350 with a 3:42  axle ratio..  1 Run 265/75R16 tires ( 31.7" Diameter ) ... 4th gear is almost useless below 45 MPH but when in "OD" position on the shifter it will shift into 4th & then lock the convertor .... It will lug the engine down to the point of being un-responsive ...    I normally run in "3rd" gear on surface streets & only use O/D when on the highway ... My '87 Suburban had the same engine / trans / rear axle ratio BUT had P235/75R15 tires ...  It would run in O/D at 40MPH all day long without issues ... The only "positive" thing about the way my truck is geared is that "passing gear" ( A 4/3 downshift )  is still available at 80MPH ....




Bob ....

[Hooley]

junkyardjeff,
                  Is that a 9" Ford in your Bronco?
Is the RPM's going down the road OK for you?  If they are you might just need to fix the clunk in your rear end. Would be money ahead. But if you want change go for it. You can figure your cruise RPM's with math or arithmetic [not sure if i can still spell it]  With that tall of a tire it makes a low gear feel much higher.

    About all I know.
       Hooley

[junkyardjeff]

It has a 8.8 and thinking about going with a 9 inch,it will go into o/d at 40 and the motor is turning about 1100. Going 60 its turning about 1700 so maybe its not going to get any better mileage with different gear and might start getting worse mileage,I have never taken it on a long trip to see what the gas mileage is so I will do that before I change the gears.

[zzford]

I'd stick with what you have. I had a 3:50 with a four speed in my coupe with the 31" tires and was very pleased with the choice.

[slocrow]

I don't think the numerical change is worth the price of the gears. Now if you're changing out the entire pig well it might be worth a try to check the results while you repair yours but then you'd have to have access to a Junkyard, Jeff.