Wrong Gear Ratio Factory Installed 35’s

[Bitching]

May I hear from anyone who has factory installed lift with 35’s Dana 44 3.73 ratio?
Although I have a lead foot, I’m driving cautiously to break the engine in and getting 13 mpg.
Odometer is 5mph slower than actual speed.
All dealer installation is supposed to be under warranty.
I suspect the auto transmission torque converter will fail.
With respect to preventative care, has anyone negotiated with dealer to change gear ratio?

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[Bitching]

P.S. original factory tires were 32’s, therefore I suppose gear ratio ought to be 4.10?

 

[Kevin_D]

What did you buy ?
What does the window sticker say the final drive ratio is?
What is your engine RPM at 60mph?

Kevin

 

[Bitching]

What did you buy ?
What does the window sticker say the final drive ratio is?
What is your engine RPM at 60mph?

Kevin

Window Sticker:
Standard Equipment
3.73 Ratio
Optional Equipment
32-inch LT255/75R17C Mud-Terrain

Dealer Installed
2.5” Lift w/35” Wheels & Tires

 

[XraytecH]

P.S. original factory tires were 32’s, therefore I suppose gear ratio ought to be 4.10?

(Final Wheel Diameter x Present Gear Ratio) ÷ Present Wheel Diameter = Final Gear Ratio

(35 x 3.75) ÷ 32 = 4.1015625

 

[Bitching]

(35 x 3.75) ÷ 32 = 4.1015625

Have you heard of anyone having the dealer correct the ratio? My thought is if I make the correction that may void in the warranty.

 

[XraytecH]

Have you heard of anyone having the dealer correct the ratio? My thought is if I make the correction that may void in the warranty.

I have not heard of a dealer correcting that.

I would assume if you left it as is and something goes wrong down the road, they would fix it within warranty.

 

[XraytecH]

May I hear from anyone who has factory installed lift with 35’s Dana 44 3.73 ratio?
Although I have a lead foot, I’m driving cautiously to break the engine in and getting 13 mpg.
Odometer is 5mph slower than actual speed.
All dealer installation is supposed to be under warranty.
I suspect the auto transmission torque converter will fail.
With respect to preventative care, has anyone negotiated with dealer to change gear ratio?

It's odd that the dealer didn't even recalibrate the speedometer. Recalibrating for those size tires will fix the shift points.

If I were you, I'd take it to the dealer and have them recalibrate your speedometer.

 

[JTBurns]

No way the dealer is going to regear for you. Sounds like a good idea for running 35's on 3.73, but that'll be totally on you. They should have the speedometer recalibrated though

 

[Deleted member 30519]

While on topic..what's the best tool out for the money to calibrate the speedo and get rid of that anoying stop start feature? I had the RC calibrator for my JL but it didn't have any other features so I dont think I would buy it again.

 

[Code 3]

Tazer JL Lite or JL Mini

https://www.zautomotive.com/product/tazer-jl-mini/

 

[Mac]

May I hear from anyone who has factory installed lift with 35’s Dana 44 3.73 ratio?
Although I have a lead foot, I’m driving cautiously to break the engine in and getting 13 mpg.
Odometer is 5mph slower than actual speed.
All dealer installation is supposed to be under warranty.
I suspect the auto transmission torque converter will fail.
With respect to preventative care, has anyone negotiated with dealer to change gear ratio?

There are many people running 35s with 3.73s, the transmission should be fine, it will be a little sluggish off the line and 6th and 7th gear are used more on the highway than 8th gear but it should not cause any problems or damage. Dealer should reset the tire size so the speedometer is correct, if they do not there are several aftermarket solutions that will allow you to correct it as well as other things, check out AEV Procal Snap or Superchips Flashcal

 

[danielspivey]

May I hear from anyone who has factory installed lift with 35’s Dana 44 3.73 ratio?
Although I have a lead foot, I’m driving cautiously to break the engine in and getting 13 mpg.
Odometer is 5mph slower than actual speed.
All dealer installation is supposed to be under warranty.
I suspect the auto transmission torque converter will fail.
With respect to preventative care, has anyone negotiated with dealer to change gear ratio?

What is your actual tire size you are currently running? At what speed is the speedo 5 mph off?

Also curious what lift did they put on it? The mopar is 2” not 2.5”... is this an actual Jeep dealer?

This install is highly suspect merely because they didn’t recalibrate the Speedo. Hey maybe they over looked, it, but it’s also like dropping your guitar off at the guitar store to change the strings and they didn’t tune the guitar. Highly suspect...

Here is a great tool to compare tire sizes and how distance/speed is affected:

https://www.tacomaworld.com/tirecalc?tires=265-75r17-315-70r18

 

[Moe_Fugga]

I wouldn’t trust the dealer to do anything properly except jack the price up on the BS aftermarket parts they lazily threw on your Gladiator. Sorry for your loss.

3.73 gears are fine with 35s. Many people are doing it including me. It won’t hurt a thing. Make sure the computer was flashed for the upgraded tire size. Again, I doubt the stealership did it, or will do it for free, so you buying a Tazer or similar product will probably be the outcome. Doing this will make your shifting better and computer data correct.

 

[Renegade]

I wouldn’t trust the dealer to do anything properly except jack the price up on the BS aftermarket parts the lazily threw on to your Gladiator. Sorry for your loss.

3.73 gears are fine with 35s. Many people are doing it including me. It won’t hurt a thing. Make sure the computer was flashed for the upgraded tire size. Again, I doubt the stealership did it, or will do it for free, so you buying a Tazer or similar product will probably be the outcome. Doing this will make your shifting better and computer data correct.

This is true.

This thread title is misleading. The correct gears were installed, but the Jeep was modified. This does not make the gear ratio “incorrect”. Would lower gears be better? Sure. Are they required for 35s? No.

OP- Buy a device to correct your speedometer and enjoy your Jeep.

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