What have i done now with this Superchips thingy

Gorhad

Gorhad

New Member
Joined
Mar 11, 2022
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8
Location
Melbourne Florida
Hi all

For some unknown reason, i can only blame it on my Parkinsons :), i erased the Gear ratio and Transfer case inputs and returned it to stock. Im running on 38" tires. Since then when i start the engine and accelerate it will change up thru the gears until the last change where it doesnt change at all. The lest say you drive a little further and come to a stop at traffic lights, they change to green and you accelerate again, Its as though its in maybe 3rd gear and doesnt change at all. But if you turn the engine off and on it repeats as mentioned before.

So the codes i have are P0731 & 732 Gear 1 & 2 Incorrect ratio

So i have tried setting the ratio to 4.30, 4.56, 4.63, 4.88 etc but doesnt rectify it

Called superchip but they said they havnt a clue

Any assistance would be greatly appreciated

Thanks in advance
 
First, tell us about your vehicle- year, model, engine, manual or auto trans, etc.

1. I'm going to assume you don't know what the actual gearing is based on your statement that you're inputting different ratios to no avail. So, step 1 is to determine the actual gearing. Was the Jeep regeared by you or a previous owner? If not try this first- enter your VIN on this site for the build sheet, which will tell you the factory gear ratio:

https://www.nathanson.org/davesays/2019/buildsheet-for-jeeps-vin/

Or, you can look on the left side of the differential cover and there should be a tag with a number which includes the gear ratio:

1649162641225.png


Once you've got the gearing figured out, you'll need to input the tire size to calibrate speedo and shift points for the transmission. Don't assume because you have 38s, the actual height of the tires is 38.
1. Adjust and correct air pressure to all 4 tires as you normally tun them on the road.
2. Individually measure ground to top of tire height for all 4 tires, to the nearest 1/4" if possible.
3. Divide the heights by 4 and use that number as your tire height.
This will set your speedometer and shift points for your transmission.

Check your build sheet for the transfer case info and input that as well.
 
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Thank you

Just looked around the differential cover but didnt see any tag or numbers. Tried entering the vin but it just says No records found corresponding to the VIN provided double checked vin but it didnt work
 
OK i got it was 1 digit out on vin, so it says 3.21 Rear Axle Ratio. Ill check that against what i find when i jack it up and count revolutions
 
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If you do have 38s with a 3.21 rear end, you need to seriously consider a regear. Check the optimum RPM charts below and you'll see that a 4.56 or 4.88 is the minimum you should be running.

1649182636349.png
 
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Update

So i managed to get in contact with the previous owners company that performed the lift & re gearing etc. Th kind lady looked through all the invoices and found the one relating to my jeep and told me the gearing was 5.13 with 38" tires

My son measured all 4 tires and and took the mean value at 36.75". Programmed the figures into the superchips and voila its running fine again

Thanks so much for you input very much appreciated
 
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