84 bronco 2 top speed 40-45mph????

[Bronc 2 84]

For some reason my truck won't go faster than 40-45mph.I can't figure it out.The info on the truck is
1.84 4x4
2.5spd manual
3.Has 31 inch tires
4.new cat
5.Rebuilt Carb (it had a hesitation like it was choking it self out or something but it's fine now)
6.Complete tune up

When i bought the truck it had the stock rims and tires and it drove fine then it went 60-65 ok.So after the carb was rebuilt it runs better but did not improve max speed.It does sound like it winds through gears like it's quickly hitting high rpms way before it should.So with that i've been told it might be the gearing in the trans or rear axle because of the 31 inch tires.If thats true then whats the best result to fix this problem.I thought maybe it's the clutch but theres no sign of it being the problem besides the winding up and the rpms.Well anyway any suggestions or help will be great.Thanks

P.s.if you need anymore info let me no and There is know hesitation or anything the truck starts up and runs fine.

[kolton]

srry, not saying you didnt check this or notice it. but to get them out of the way...

is your parking brake on?
are you in 4x4? or 2high?

[1highlander]

If you changed from stock to larger tires/wheels, then you need to correct your speedomoter drive, I think. When I bought my 88 it had larger tires on stock wheels, and would quikcly run out of speed. I replaced the tires with OEM size, and now it cruises easily at 70.

[sdhawks]

going with a little bigger tire wont affect u that mutch u got sumthin wrong i couldnt tell without being there but sumthin not rite

[1highlander]

That was what changed it from chugging up the mountain to taking most of them in 4th or 3rd (I live on a twisty mountain). That was 2007, and I've had no other problem with speed since then, so I'll go with that explannation. Sure is fun on days like we're having here in the hills lately!