Wrong Gear Ratio Factory Installed 35’s

[Bitching]

Yeah, I read that - no way it's a factory installed lift and 35's. That's AFTER factory, dealer or owner installed and no a dealer does what you ask, they don't swap gears unless you ask and that's on YOU since that is your request.

You bought a truck with the 3.73 ratio. You had the dealer install bigger tires and a lift. Those are accessories, not factory. So why would a dealer make a gear change? It's not part of any package and not even a factory option.
If you want different gears, it's on you.
Dealer told me months ago if I went to different tire sizes they'd reconfigure the truck - for a fee, or they'd sell me the tools to do it and I'd then have the tool forever and for future tire changes.

It ain't on them. You have to tell them what you want or want done.

It’s true, Leigh Jeep Raleigh NC. Although I paid extra for it, because it’s dealer installed, the incentive was that it’s covered by factory warranty. Whereas if I had the lift install on my own, that would have voided factory warranty. Now the problem, who stays with 35’s for 150K miles before 40’s?

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[EXTORTION]

I've saw a dealer install a non mopar 4" lift and 37s on a Sport S with stock 3:73 gears. The poor person I saw buying, bought for looks. Never asked about functionality or warranties. The dealership did flash for the larger tires. The entire lift and tire/while package and computer flash or as they called Electronic Reprogramming of On Board Computer for After Market Tires. Was $9999.00

Dealerships will sell anything without regards to the customers best interest in mind, just get the sale anyway they can.

PS, The person that bought the above Jeep, found out later that dealership voided the warranty on the Jeeps power train, even though the dealership installed the parts on their own. Dealership told customer that n9n mopar parts void the warranty. Needless to say, they have contacted an attorney

 

[ShadowsPapa]

It’s true, Leigh Jeep Raleigh NC. Although I paid extra for it, because it’s dealer installed, the incentive was that it’s covered by factory warranty. Whereas if I had the lift install on my own, that would have voided factory warranty. Now the problem, who stays with 35’s for 150K miles before 40’s?

Still not a factory installed lift. It's just plain a dealer instal..
Installing the lift on your own would NOT void the factory warranty. The lift itself is covered fully as a genuine MOPAR part. It's got 2 years. If the dealer installs it, they also cover the installation.
The only "void" would have been if you had installed it, made a mistake or messed up, didn't torque something correctly and something came lose - then it's on you..
But I think you are misunderstanding how MOPAR parts work and how things installed by the dealer work.
For example - the MOPAR brake controller in my truck - 100% covered AS PART OF THE TRUCK even though I installed it. So if it stops working, something goes wrong, I can take it in and they cover that brake controller exactly like it came from the factory that way.
The paper in the box even said "2 full year warranty" as a part, and once in the truck, it's covered as long as the truck warranty or words to that effect.
So it doesn't make a squat bit of difference - that lift kit is covered and it's covered in your truck.
If it voided any warranty no one would ever install those on their own.
I can put a 2" MOPAR lift under my truck and take it in before my truck warranty expires and it's covered for the remainder of my warranty. But if I have the dealer do it even the installation is covered - if a bolt breaks or comes loose - the dealer eats it because the installation they did is covered.
I asked them about axle swap (meaning full differential assembly) and they said - the parts are covered under the factory MOPAR warranty on the parts - the install is covered by the dealership if they install it. EITHER WAY, the axle assemblies are covered. It's just the difference if the INSTALL is covered or not.
You are not getting anything more or better than any of us get - other than the dealer has to cover any installation screw-ups if they do it. If they forget to tighten something and it wears a hole in another part - they cover it. That's the biggest difference.

 

[ShadowsPapa]

I've saw a dealer install a non mopar 4" lift and 37s on a Sport S with stock 3:73 gears. The poor person I saw buying, bought for looks. Never asked about functionality or warranties. The dealership did flash for the larger tires. The entire lift and tire/while package and computer flash or as they called Electronic Reprogramming of On Board Computer for After Market Tires. Was $9999.00

Dealerships will sell anything without regards to the customers best interest in mind, just get the sale anyway they can.

PS, The person that bought the above Jeep, found out later that dealership voided the warranty on the Jeeps power train, even though the dealership installed the parts on their own. Dealership told customer that n9n mopar parts void the warranty. Needless to say, they have contacted an attorney

The dealers all told me, and I have read it in warranty papers - if it's a MOPAR part, the part is covered under warranty. If the dealer installs it, the DEALER covers the install, MOPAR covers the part. Once I installed my brake controller, it was covered as part of the truck under the truck warranty. Apparently if the truck warranty was gone, the part would be covered under standard MOPAR parts warranty. That's how I read it anyway.
They'll tell you a lot to get you to buy the parts and the install from them.
Except the dealer I bought my truck from does no custom stuff - standard only.
And the dealer I've been going to for WAVE stuff and warranty work actually is more honest and says "you can do this yourself, we'll sell you the stuff" or they'll do it, my choice. If I tell them to do it they said the installation is covered by them. They don't really seem to care who does it.
When I went in with the brake controller issue - they didn't give a rip. I asked and they said "it's a MOPAR part, it's covered, and your truck has warranty, no matter what, the fix would be covered - and that that time they had no clue what was wrong!

 

[Mjolnir]

Lol what is this thread.

Did you ask the dealer to regear, then proceed to pay the dealer to regear?

No you didnt.

So why are you surprised you have the factory gears? This makes no sense.

The dealer should have flashed the computer for larger tires, but that is the only thing they should have done. By all means regear, it is deff better. However expect to pay another $1500+ for this.

 

[jdwhichard]

regear on the dana 44s is super easy ,shims are on the outside of the bearing so much easier than dana 30s or 8.8 . 4.56 min for max efficiency . im running both 33s of the highway and 35s when offroading 4.56 is going to be the first thing i do as soon as the 36k warranty runs out . Its a truck the cruising rpms are arldy too low from the factory with4.10s and 245/75r17 for epa mileage the 3.6 need to be turning around 1800 to 2k at highway speeds

 

[jdwhichard]

https://prodigyperformance.com/blog/jeep-wrangler-gear-ratio-calculator/

 

[brianinca]

I dunno, a transmission shifting gears is exactly what it is for. I can't imagine being upset that the powerband of the engine is being correctly selected for the load.

It drives me nuts when someone with a manual transmission lugs the shit out of the engine because they can't be bothered to downshift.

I have a mojave with 4.10 and 33's.

I understand that many people are saying it won't blow up and everything will be fine but I gotta tell you, I can't imagine running like that.

Mine is just about tolerable. But close to bugging me as is. It shifts out of 8th a lot on the highway if there is any incline or wind.

I was considering 35's but after putting 5000 miles on the 33's, I would not think of it without regearing one or 2 steps.

I like my vehicles to run "as intended" and driving in 6th on the highway (although not damaging) would drive me absolutely nuts. Not to mention that towing would be severely diminished.

The argument that "it won't blow up but if it does they will cover it under warranty" does not seem like sound reasoning to me for a vehicle that I want to last a long time.

My opinion. And worth well, nothing I guess.

 

[Renegade]

I dunno, a transmission shifting gears is exactly what it is for. I can't imagine being upset that the powerband of the engine is being correctly selected for the load.

It drives me nuts when someone with a manual transmission lugs the shit out of the engine because they can't be bothered to downshift.

People also aren’t accustomed to what an 8-speed double-overdrive transmission is SUPPOSED to do. They try to apply 4/5-speed characteristics to their expectations, and think something isn’t right when it “hunts” for the right gear. It’s not hunting, it’s SELECTING the correct gear.

 

[jurfie]

OP said 2.5” dealer installed lift; very possible it is not the 2” MOPAR lift. Lots of dealers install rubbish lifts for look alone and charge a huge markup.

Regearing is not part of any lift, MOPAR or otherwise. 3.73s with 35s will be barely tolerable at best. A little research in advance would tell anyone that, but how many buyers are that savvy? A local dealer here used to put cheap lifts and 35s on JKs with 3.21s and happily sell them unsuspecting to buyers who just wanted the look. As mentioned, most dealers just want the sale. I’m sure they’d be happy to charge you for a regear if you ask them.

Agree that recalibration should have been part of the deal, so I’d push back for that. They’ll probably try and charge you for it now, but I’d raise a fuss until they did it for free. Or, as others suggested, buy a Tazer Mini and do it yourself; there are a bunch of other features and benefits in having one making it worthwhile getting.

 

[ShadowsPapa]

People also aren’t accustomed to what an 8-speed double-overdrive transmission is SUPPOSED to do. They try to apply 4/5-speed characteristics to their expectations, and think something isn’t right when it “hunts” for the right gear. It’s not hunting, it’s SELECTING the correct gear.

But it isn't good heat-wise and wear-wise when it's shifting 8th to 6th, then to 8th again every 10 seconds. I timed it and on one trip for about 30 minutes it never held any gear for more than a few seconds, sometimes shifting as often as every 5 seconds, about the longest it held was perhaps 30 seconds.
My ford had a button where you could lock out that BS and it would hold gears better. Yes it was for trailer towing but I also used it without a trailer now and then.
Since the PCM update/flash it does a whole lot better but still- 1500 rpm on the highway is nuts. Why should it even choose 8th under such conditions when it's going to drop back out in seconds. What good is going to that second OD gear for 3, maybe 4 seconds? You gain nothing. Hit a tiny incline and the engine starts to lug before it shifts. I'd have downshifted long before that.
That's the other point - it actually DOES lug before it shifts, I've seen it drop as low as 1400-1300 rpm before deciding the engine's in trouble before it shifts.
Those who disagree MAYBE had a truck that's shifting properly and aren't accounting for some of them having poor programming or issues.
When they hold a gear for a mere 3 seconds, and keep shifting up and down, multiple times in a span of 5-10 seconds, something's amiss.
I liken it to a thermostat that's set to turn off when the desired temp is hit and back on when it drops half a degree below that temperature - on-off-on-off-on-off constantly, never resting.
So they make thermostats have a range - shut off a degree above the desired temp, don't come back on until it's a couple degrees below the desired temp.

These engines don't have shit for torque or power at 1300-1400 RPM and then to try to hold a gear at 1500 rpm and hit a barely perceptible incline and start to lug before they shift? It's nuts.

 

[Renegade]

But it isn't good heat-wise and wear-wise when it's shifting 8th to 6th, then to 8th again every 10 seconds. I timed it and on one trip for about 30 minutes it never held any gear for more than a few seconds, sometimes shifting as often as every 5 seconds, about the longest it held was perhaps 30 seconds.
My ford had a button where you could lock out that BS and it would hold gears better. Yes it was for trailer towing but I also used it without a trailer now and then.
Since the PCM update/flash it does a whole lot better but still- 1500 rpm on the highway is nuts. Why should it even choose 8th under such conditions when it's going to drop back out in seconds. What good is going to that second OD gear for 3, maybe 4 seconds? You gain nothing. Hit a tiny incline and the engine starts to lug before it shifts. I'd have downshifted long before that.
That's the other point - it actually DOES lug before it shifts, I've seen it drop as low as 1400-1300 rpm before deciding the engine's in trouble before it shifts.
Those who disagree MAYBE had a truck that's shifting properly and aren't accounting for some of them having poor programming or issues.
When they hold a gear for a mere 3 seconds, and keep shifting up and down, multiple times in a span of 5-10 seconds, something's amiss.
I liken it to a thermostat that's set to turn off when the desired temp is hit and back on when it drops half a degree below that temperature - on-off-on-off-on-off constantly, never resting.
So they make thermostats have a range - shut off a degree above the desired temp, don't come back on until it's a couple degrees below the desired temp.

These engines don't have shit for torque or power at 1300-1400 RPM and then to try to hold a gear at 1500 rpm and hit a barely perceptible incline and start to lug before they shift? It's nuts.

My point is simply that what we knew to be true in past Jeeps isn't necessarily true in the JL/JT drivetrain, especially with the 8-speed. For example, The JK automatic's 1st gear ratio was 3.59, while the JT's 1st gear ratio is 4.71. A JT with 4.10 gears has the first gear final drive ratio equivalent of a JK with 5.38 gears. Absolutely no one would claim that 5.38 gears are too high for 37s in a JK. Add to it that the JL/JT transmission has 4 gears between 1st gear and the 1:1 sixth gear, while the JK only had 2 gears between first and 4th. This contributes to MUCH better acceleration. The 8th gear is where our JTs get a little out there, at .67 overdrive. I will agree that 8th gear is pretty much useless when larger tires are added, but you do wind up in about the same RPM range in 7th as you would have been in 8th with stock tires. None of this is to suggest that a Jeep with larger tires wouldn't benefit from regearing. It's just to point out that the old rules need to be at least revised when considering what is and isn't reasonable with regard to tires/gears in the automatic JT. If you think about gearing as a sliding scale, what you wind up missing after putting on larger tires is on the very bottom end. Essentially, you are missing 1st gear, but gaining a useless and unnecessary 8th gear. Everything between there is going to be made up by the transmission shifting gears, and you essentially have a 7-speed automatic. This is still BETTER than a 5-speed automatic in a JK with 5.38 gears.

 

[ShadowsPapa]

My point is simply that what we knew to be true in past Jeeps isn't necessarily true in the JL/JT drivetrain, especially with the 8-speed. For example, The JK automatic's 1st gear ratio was 3.59, while the JT's 1st gear ratio is 4.71. A JT with 4.10 gears is has the first gear final drive ratio equivalent of a JK with 5.38 gears. Absolutely no one would claim that 5.38 gears are too high for 37s in a JK. Add to it that the JL/JT transmission has 4 gears between 1st gear and the 1:1 sixth gear, while the JK only had 2 gears between first and 4th. This contributes to MUCH better acceleration. The 8th gear is where our JTs get a little out there, at .67 overdrive. I will agree that 8th gear is pretty much useless when larger tires are added, but you do wind up in about the same RPM range in 7th as you would have been in 8th with stock tires. None of this is to suggest that a Jeep with larger tires wouldn't benefit from regearing. It's just to point out that the old rules need to be at least revised when considering what is and isn't reasonable with regard to tires/gears in the automatic JT. If you think about gearing as a sliding scale, what you wind up missing after putting on larger tires is on the very bottom end. Essentially, you are missing 1st gear, but gaining a useless and unnecessary 8th gear. Everything between there is going to be made up by the transmission shifting gears, and you essentially have a 7-speed automatic. This is still BETTER than a 5-speed automatic in a JK with 5.38 gears.

You are coming at it from a 4.10 Rubicon perspective I suspect.
On the 3.73 they may as well lock out 8th as it's worthless unless you are doing 75 or better on the level - and around here, the level doesn't exist.
I have yet to see mine in 8th more than a few seconds.
The other day there was a slight breeze out of the east - I was heading home on I80/35 on the north side of Des Moines. I never saw it leave 7th, I was doing 70-75 - and that's how worthless 8th is. Any wind or breeze and it can't handle it. I laughed after I realized what was going on - really? A bit of a breeze and I'm doing 70 or so and it can't handle 8th gear?
Seriously, a stock Overland with 32.8" tires just can't and won't stay in 8th for more than mere seconds (and you won't reach double digits) in this state. The engine LUGS, literally, before it finally downshifts even in lower gears.
I've gotten to the point I've started watching the tach a bit more closely - and it never really stays in a good RPM range, always way too low for the curves it has and I am not kidding or exaggerating when I say you can feel the engine literally "bog down" before it will downshift.
The transmission may be fine but the shift mapping is stupid in these with stock gears.
It needs to get and stay above the RPM it's told to stay in.
My wife's Grand Cherokee does a hell of a lot better. 8 speed, 3.6

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