speedo still 5mph off with 4.88's and 33's??? help....

[Thurlo76]

ok whats the deal??? i just for giggles today got radared to see how close i got my speedo after my 4.88 swap and my speedo said 26mph then my actuall speed was 21mph. i thought 4.88's put the speedo at actual speed?

i have a 1987 toyota 4runner sr5 5 speed. tranny, t case, and engine came from an 86'. the gears came from a 95' 4runner and they are the "stock" 4.88's from it. i have 33'' tires. i heard i could have a different t case than most. i didnt know how true that could be because i couldnt find anything about "special t cases"

any ideas on why its like this??? or is that usual for the speedo to be off???

 

[hoe_nah]

was the 4runner auto? the one you got the gears from? did you count the ring amd pinon before install? sounds like you got 4.56s in there

 

[Thurlo76]

yes the 4runner i got the 3rd member and front pumkin from a 95' v6 auto. it had 39 teeth on the ring gear. i believe the 4.88's were 8x39. i had 4.56's in my truck before i swapped in the 4.88's. i felt a difference. so i dont think i have 4.56's. plus i put the 2 3rds next to eachother (the 4.56's and 4.88's) and the ring gear on the 4.88's was way skinny compaired to the 4.56's.

 

[fourwd1]

... i have a 1987 toyota 4runner sr5 5 speed. tranny, t case, and engine came from an 86'. ... i heard i could have a different t case than most. i didnt know how true that could be because i couldnt find anything about "special t cases"

"Different" t-case or not, it's still 1:1 in High range, just like every other one.
So no effect on your speed or RPM's.

And the only "different" case in 86 would be the one behind the 4 cyl turbo engine.

As for your problem, yes, I think you should be closer.
The difference is a percentage, not a constant.
If you can find out the actual vs gauge speeds at various speeds, you can figure out the percentage you are off.

 

[Thurlo76]

well how do i fix it??? and is anyone elses like this??? i thought 4.88's put 33's back to stock. this isnt stock. i put on a set of 35's today (for giggles) and the speed was spot on. can anyone explain that???

i thought you needed 5.29's for the 35's to be stock. i know these gears arnt 5.29's.

 

[Hyde802]

i thought you needed 5.29's for the 35's to be stock. i know these gears arnt 5.29's.

Power wise, not spedo wise. It brings you close to the "stock" power. But once you add lift and bigger tires, you may be CLOSE to stock..bout youll never be stock again.

 

[Thurlo76]

Power wise, not spedo wise. It brings you close to the "stock" power. But once you add lift and bigger tires, you may be CLOSE to stock..bout youll never be stock again.

i guess that makes more sence, thanks alot