4.88 help
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4.88 help
I have a 2002 f250 5.4 6inch lift and 315 75 r16 I just had 4.88 put in front and rear buy a local shop from 3.73 . The problem I'm having is now when I get to 75mph on the speedometer (80MPH ON GPS )it kinda jerks and such and wont go any faster didnt have this problem with the 3.73 feels like I might be hitting the speed limiter? Ideas
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not tuned or recalibrated for tires or gears and yes could do 90 easy with the 3.73 also not a fleet truck I was under the assumption that it didnt need adjusted for the gears
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Well with the 3.73 the speedometer was 1mph off with the 315 75 tires now with the 4.88 its 3 to 5 mph off and I cant go over 80 mph though with the 3.73 i could get the truck up to 90 mph never tried to go faster then that
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Joined: May 2017
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From: Southern OH
However after doing some math 2700 rpm with stock size tires (32") and 3.73 gears in O/D would put you at 97 MPH which is right at where the speed limiter is from the factory. With 4.88 gears at 2700 RPM you would be at 74 MPH which is where it is cutting out on you, so the speed limiter might be based on your RPMs in overdrive rather than on the speed sensor, just a thought.
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So how do you like the 5.4/35's/4.88 combo?
I installed 35's on my 5.4 (i have 4.30 gears) and I HATED it. Didnt feel it had the "grunt" anymore....was gonna swap in 4.88 but my buddy gave me the same amount of cash i just paid for the new tires so i sold them to him. Now i want another set of 35's but I'll defiently be doing 4.88 that same week LOL
I installed 35's on my 5.4 (i have 4.30 gears) and I HATED it. Didnt feel it had the "grunt" anymore....was gonna swap in 4.88 but my buddy gave me the same amount of cash i just paid for the new tires so i sold them to him. Now i want another set of 35's but I'll defiently be doing 4.88 that same week LOL
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From: Maryville, TN
While I don't really know about your year and transmission, my '16 shifted funny when I regeared to 4.88's. After programming the computer for the gears, everything was fine. Try turning OD off and see if it cuts off or goes all the way to redline. I don't remember the exact speeds because it's been 20 years, but I had a 94 Dodge Ram that cut off around 100. But you could lock out OD and it would redline 3rd gear somewhere around 112.
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