Mods no effect on 6 speed

[DanW]

I agree it is a very easy manual transmission vehicle to drive. The clutch is light and the throws are easy. It’s mostly the gearing. If you drive in 4th-6th gear between 1.5k and 2.5k rpms, you get a strange pulsing. If you don’t mind thrashing the motor and driving it harder, I could see someone enjoying a manual JL/JT.

I've not experienced that pulsating, at all and 100% of the time when cruising I'm between 1.5k and 2.5. It didn't do that before or after the re-gear from 4.10 to 4.56.

This engine does love to rev, and it pulls hard all the way to red line. It's a real hoot. The harder you drive it the more fun it is. I put a Magnaflow axle-back exhaust on mine and it is just pure music when you get on it.

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[DanW]

100%. I noticed that in the shifts up to second, third and 4th I need to be above 3200RPM to have the revs stay above 2100RPM after the shift - I think this is about where the VVT switch occurs. The problem is that 3200RPM in 3rd is about 55mph (I have a JTR on 35s with stock 4.10 gears). The point is that if you want to avoid bogging the 6MT or have any decent acceleration you spend a lot of time in 3rd and 4th around town. I never get into 6th (other than flat land cruising) below 60mph, and if there is a head wind forget it.

If you want some real fun, nail it and feel the kick in the pants it gets at 4500rpm. It is very noticeable and continues to pull hard all the way up to red line. LOTS of fun!

And this engine actually does better when run hard. If run like a grandma, the oil at the valve stems can evaporate away. Hard full throttle runs to high rpm throws fresh oil in there, virtually eliminating wear at the valve stems.

So run the hell out of it, enjoy it, and feel good about it!

 

[ShadowsPapa]

Oil evaporate away? Whew, hope not. That takes some serious heat, like over 270 degrees or better to start evaporating off the lighter parts.

These have oil up to the heads from the main oil gallery to the camshaft oil port, to the hydraulic lash adjusters and to the cam lobe spray nozzles. There's constant oil spray all over and around the cam, lash adjusters, lifters and thus, valves.
The valves get sprayed with oil constantly.
If there's not enough oil up there, something else will suffer first, IMO.

And, since these maintain the same oil pressure up through 3500 RPM and then kick it up, there's no difference in the oil pressure or flow idle to 3500 RPM.

 

[DanW]

Oil evaporate away? Whew, hope not. That takes some serious heat, like over 270 degrees or better to start evaporating off the lighter parts.

These have oil up to the heads from the main oil gallery to the camshaft oil port, to the hydraulic lash adjusters and to the cam lobe spray nozzles. There's constant oil spray all over and around the cam, lash adjusters, lifters and thus, valves.
The valves get sprayed with oil constantly.
If there's not enough oil up there, something else will suffer first, IMO.

And, since these maintain the same oil pressure up through 3500 RPM and then kick it up, there's no difference in the oil pressure or flow idle to 3500 RPM.

This is really not something to worry about. I only brought it up because it is interesting. It is an exceedingly rare condition caused by extended periods of extremely light driving. It came up in a fun conversation about Pentastar quirks with my buddy who designed the gen 1 Pentastar. So everything I've said comes straight from him. He's still with Stellantis but has not done Pentastar design work since before the PUP version in the JL/JT came out. So there may be some differences in the valve train design. He is not 100% familiar with all the changes in this generation.

Oil will still have some evaporation at normal temps and a normal engine can have hot spots that easily hit the 260 degree mark where NOACK volitility is measured. Oil can be at 13% NOACK evaporation and still meet API SP/GF6. A high end oil like Mobil 1 EP is around 7 or 8% for NOACK. Most 0w20's will fall somewhere in between. (Dexos 1 Gen 2 also allows for up to around 13 or 14% evaporation, as well.) Remember, too, that this oil in the valve stems of the Pentastar is not circulating, but staying put in one place. So it does get hotter than oil that is circulating. But you'd have to drive it like a granny for a looooong time. He was warning against "granny cycling" the engine, which is what they call it. If you punch it now and then, no worries. It doesn't take much to splash the tiny amount of oil up in there that is needed to keep things lubricated.

He told me they had seen a couple of extreme cases and actually created what they call the "granny cycle" test to see what was going on. The good news is that again, you'd have to drive it like grandma for a very, very, long time for the oil to go away. BUT, if you do that, you will ultimately get excessive wear on the valve stems. The other good news is that it is an extremely rare condition. I think my Aunt Birtha would be the only one I know that could subject a Pentastar to that issue. She never drove more than 20mph and only to and from the grocery and church, Lol.

His point wasn't really to warn about this, as it is rare and unusual. His point was to tell me that the Pentastar likes to be run hard and that this is good for it. And by punch it, he means floor it and run it into high rpms, which is where you'll see the higher oil pressures. It'll splash right up in there if even at higher pressure for only a second or two. It doesn't take much.

He has a Chrysler 300 with somewhere around 200k on it by now, btw. He is running it until it croaks. He thinks it will go 500k, at least. He's running 5w20 Pennzoil Platinum or Mobil 1 and Mopar filters in it with 7,000 mile oil changes. And he said he has run it hard since new and that it runs perfectly.

My Pentastars will never have to worry about this. Especially the one with the manual transmission. I just can't keep my foot out of it. Lol!

 

[COwens]

I definitely wind mine up... sometimes I even coast in 3rd gear @ 3000+ RPMS.

I will say moving from 33" to 37" (with 4.10) has changed "where" my shift points are and I'm still learning a bit. Especially from 2nd -> 3rd it feels like I need to go well into 3000 RPM range before going into 3rd or I'm out of the power band when 3rd engages (sub 2000 RPM). This is felt mostly on steep hills.

I also find myself at 75 MPH in 4th gear quite often.

As others have said, 6th gear is gone but I don't mind. I would have been happy with a correctly-spaced 5-speed over a tall OD 6th.

I've thought about swapping the ASIN for a 5-speed Tremec and new clutch... not sure if the Tremec will fit.

Totally agree. I look at RPM over speed most of the time

 

[NC_Overland]

I’m not afraid to let mine rev. It does like to rev and has a nice little growl for a V6. It sounds a lot better than my 3.6l V6 in my 2017 Canyon, but I wish it had that 4K-7k rpm pull. That truck is quick and fun to floor it and let it rip. Weird engine for a truck, it hits max hp at 6800 RPM and has a 7400 RPM redline.

 

[BackcountryNV]

I haven’t done the recall. It’s a joke. The after market clutch is so much better. Earlier take up, more positive engagement. Better crawling, better backing, better towing, better take offs on the street. Just goes much better. Only con is an increase in pedal effort that I don’t even notice anymore.

I wouldn't mark that as a con I would love to have a little bit more pedal feel to the clutch. Guess I'm going to have to add another upgrade to the list... just when I thought I was getting close to done lol.

 

[Bbannongmu]

I wouldn't mark that as a con I would love to have a little bit more pedal feel to the clutch. Guess I'm going to have to add another upgrade to the list... just when I thought I was getting close to done lol.

It never ends. The Centerforce clutch is a game changer. Well worth the investment
J ust
E mpty
E very
P ocket

 

[jcarbs]

Not to beat a dead horse - but how is it only a 5lb per corner increase? Going from 33's to 37's when I look at tires is quite a bit more than just 5lbs let alone the change in factory wheels.

I'm looking at going from my stock wheels and Firestone MT's (255/75r17) to Lt285/75/17 with Warn Diamond Cutter wheels and that's over 11 lbs a corner. The tires are the biggest weight change, so 5lbs just doesn't sound right.

 

[Bbannongmu]

Not to beat a dead horse - but how is it only a 5lb per corner increase? Going from 33's to 37's when I look at tires is quite a bit more than just 5lbs let alone the change in factory wheels.

I'm looking at going from my stock wheels and Firestone MT's (255/75r17) to Lt285/75/17 with Warn Diamond Cutter wheels and that's over 11 lbs a corner. The tires are the biggest weight change, so 5lbs just doesn't sound right.

I went from stock Falken Wildpeaks in 285/70R17 at 63 pounds each for just the tire to Mickey Thompson Baja ATZP3 in 37x12.50 at 84 pounds for each tire. I used stock wheels so no change there. I added 21 pounds at each corner (or about 33% increase in unsparing weight) so 84 pounds total of unsprung weight added. (didn’t change the spare yet). The added weight, gearing effect and resistance was noticeable and I’ve since gone to 5.13 axle gearing and its better than stock. It’s simple physics and statistics. YMMV.

 

[jcarbs]

I went from stock Falken Wildpeaks in 285/70R17 at 63 pounds each for just the tire to Mickey Thompson Baja ATZP3 in 37x12.50 at 84 pounds for each tire. I used stock wheels so no change there. I added 21 pounds at each corner (or about 33% increase in unsparing weight) so 84 pounds total of unsprung weight added. (didn’t change the spare yet). The added weight, gearing effect and resistance was noticeable and I’ve since gone to 5.13 axle gearing and its better than stock. It’s simple physics and statistics. YMMV.

That's why I said the 5lbs per corner just doesn't add up. That big of a tire change should have resulted in more weight. Out of curiosity what did you think of those Falken Wildpeaks?

 

[Bbannongmu]

That's why I said the 5lbs per corner just doesn't add up. That big of a tire change should have resulted in more weight. Out of curiosity what did you think of those Falken Wildpeaks?

Yup - physics don’t lie.
The wildpeaks were decent. My sister has them on her Jeep TJ now. I love my Mickey Thompson’s. Great grip in snow, rocks, mud and reasonable noise on the road.

 

[Wally's Dad]

True. To each their own. The right axle gearing (I have 5.13 with 37” tires) makes a huge difference. I have a Centerforce clutch and wow - by far the best Manual setup I’ve ever had in about 30 years of driving.

Where were you able to find your clutch kit? Do you know if there is a difference between your 2020 and my 2021?

 

[Orange01z28]

I have the same tires and similar wheels on a rubicon automatic. I have a lot of hills in my area. It wasn't a dramatic negative impact but was noticeable. About four weeks ago I did 5.13s. Even on surface streets I am almost always in 8th and rarely kick down below 6th unless I stomp on it. In daily driving I have picked up around 3.5 mpg. Obviously the difference between manual and automatic are significant but after the gears the feel is much improved. When visiting my parents in the north georgia mountains(small hill like structures to those of you with the tall things with the frozen white stuff on top) the part of my brain that contains mechanical sympathy feels much more relaxed. I am very happy with the change in driving dynamics.

What's your rpm on the highway @ 80?

 

[Bbannongmu]

Where were you able to find your clutch kit? Do you know if there is a difference between your 2020 and my 2021?

I had an order in with Centerforce directly in 2020 and it got cancelled. I got an early production model dual friction clutch. It is awesome! Should be available on their website soon - Quadratec is accepting back orders now.

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