rpm?

[walrus101]

to the guys who have installed 4.56 or 4.88 in there rigs. what is the rpm that you are running at 70mph, with what size tires? does the transmission shift frequently with these gears, because my auto shifts to much out of o/d? i noticed in 'which gear' post yall were talking bout these are the gears to use. i am runnin 33x12.50 and looking at changing the gears also;this is my daily driver and i travel the highway regularly. i wasn't planning on going that steep, but if you say these are the best gears, i'll believe ya.

walrus101

goo goo gaju

 

[BB454]

Walrus I don't think any of those gears will ever get your truck up to even 60mph.

BB454
IF IT DOES NOT HAVE 8 PISTONS - IT'S BROKEN !

 

['73 K5]

On my old Jeep with 35's and 4.56's I was doing about 3000 RPM at 65. Thats with no overdrive.

'73 K5
Chevy good...Ford bad

 

[6.2Blazer]

With 33" tires, 4.10 gears would probably be fine, especially if you spend a lot of time on the highway. Concerning the trans shifting out of O/D all of the time, this just means you should be driving it in "D" (not in overdrive). I never shift the trans into O/D until I'm on a straight, level section in which I can maintain at least 50 or 55 mph for long periods of time. The truck is never in O/D in town or on curvy back roads. Everytime the trans shifts into and out of O/D it is causing wear and heat buildup which shortens the life of the tranny.

 

[88Jimmy]

On my 88 Jimmy with Dana 60 14B FF 4.56 gears BFG A/T 35x12.5x16.5 @ 70mph 2350 in overdrive @ 65mph 2200
As for kicking out of overdrive it does not it kicks out of lockup TCC.
next time you are going up a hill and it kicks out of OD watch the tach then drop it in to third gear and see the tach move up 3 to 5 hundred rpm.


350 Vortec TPI D60 14Bolt 4.56 4"lift 35 BFG A/T

 

[walrus101]

thanks for the input. i've been keeping it in drive in town and up to bout 60mph then i go ahead and put it in o/d. what is lockup tcc?

walrus101

goo goo gaju