First Tow with the Gladiator and comparing it to the same trip using my old RAM with the 5.7 and our old Dakota before that

[wannajeep]

Similar scenario here - went from a Ram 1500 with 5.7L Hemi (it had the ZF 8HP70 transmission I think) - then went to Gladiator, manual with 3.6L V6 Pentastar. Towing a 3,300 lb trailer. Night and day. Ram had power to spare, clear winner. I knew that going into it when I traded it for the Gladiator. Still very happy with the Gladiator; it's been towing and hauling nearly every week this year and is doing well. It's no 5.7L Ram but then the Ram is no Jeep.

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[LittleFish]

Similar scenario here - went from a Ram 1500 with 5.7L Hemi (it had the ZF 8HP70 transmission I think) - then went to Gladiator, manual with 3.6L V6 Pentastar. Towing a 3,300 lb trailer. Night and day. Ram had power to spare, clear winner. I knew that going into it when I traded it for the Gladiator. Still very happy with the Gladiator; it's been towing and hauling nearly every week this year and is doing well. It's no 5.7L Ram but then the Ram is no Jeep.

Yes, there is absolutely no comparison to the power of the 5.7 Hemi. Like you, I was well aware of that when purchasing the Gladiator. I'm quite pleased with the Gladiator and could care less if I go over the Malahat at 70km/h vs 80 km/h. I wouldn't want to be going over it any slower than that though.

 

[LittleFish]

If we assume that the lower second gear exactly compensated for the difference between 3.73 and 4.11 gears then your speed would be exactly the same.

If the difference between second and 3rd gear is greater than the difference between the two differentials, then you would go slower at the same RPM. But you could always rev the engine higher to go faster.

If you could get me the actual gear ratios of 2nd and 3rd gear in the transmission, I could do the math.

With all the right numbers, we could plug them into this and come up with RPM at various speeds in each gear with each differential.

But it doesn't change that the overall gearing is what matters.

Overall gearing is a result of the

transmission gear ratio x transfer case gear ratio x axel ratio x tire rolling diameter

Since you aren't changing the transfer case or tire size, we can eliminate those from consideration here.

Here's an example.

if the 2nd gear is 3:1 and the differential is 3.73:1 then the overall ratio is 11.19 : 1
If 3rd gear is 2.72 : 1 and the differential is 4.11 : 1 then the overall ratio is 11.19:1.

Get it. Same gearing, different way to get there. In this situation, your engine will feel the exact same load and go exactly the same speed at a given RPM.

Transmission and additional specs:

https://s3.amazonaws.com/chryslerme...Gladiator_SPECS45esjosaf5fntgd91vsq2ll8dr.pdf

dcmdon,

It appears all Gladiators use the 850RE Eight Speed Overdrive Transmission when combined with the 3.6L Penstar V6.

850RE Gear Ratios: 1st 4.71, 2nd 3.13, 3rd 2.10, 4th 1.67, 5th 1.28, 6th 1.00, 7th 0.84, 8th 0.67

Keep in mind, I was hitting 4500-5000 RPM to maintain 70km/h under that load. Transmission Temps hit 102*C (215*F) (I would be pulling over to cool down if I hit 104*C/220*F), Engine Oil Temp 109*C (228*F) (I would be pulling over to cool down if I hit 121*C/250*F). While I wasn't at the MAX RPM of 6600RPM, I didn't exactly have a lot more in the way of usable RPM's to work with due to the temperatures I was already hitting. As we both agree, the harder you push it, the hotter it gets... I'm curious how you plan to work out the RPM's between the two differential gear ratios? Please show the math as I truly am interested in how this all comes together and I'm sure the others reading this thread are equally as interested.

Tires are the stock 245/75R17's

Cheers,
LittleFish

 

[dcmdon]

2nd is 3.13
3rd is 2.10

3.73 gears in 3rd has an overall reduction of 3.73 * 2.1 = 7.8.
4.10 gears in 3rd has an overall reduction of 4.1 * 2.1 = 8.6
3.73 gears in 2nd has an overall reduction of 3.73 * 3.13 = 11.6

We are holding transfer case ratio and tire size constant so we don't need to include those in our calculations. (I think high range in a jeep transfer case is always 1:1 anyway, but I'm not sure)

So this means that if you were turning lets say 4500 rpm with 3.73s and you install 4.10 gears in back, you will then be turning 4946 RPM

If you drop down to 2nd gear with the 3.73s, you will be turning 6700 rpm.

So in this specific example, the regeared rear end gets you an extra 400 RPM.
Dropping down a gear gets you an extra 1700!!.

But again, this is one specific example. You may find that at a different speed the 373 gets you in a sweet spot.

The bottom line is that what matters is the overall reduction ratio. In some cases one axel ratio may put you at the right rpm at the right speed. And in another case, a different ratio puts you at the right rpm at the right speed.

So on a different incline, the 3.73 in 2nd may be the right gear.

One other thing. Remember that heat is a function of power. Power is a function of speed. The faster you are going the more heat you make. It doesn't matter if you are making that power by running full throttle at a lower RPM or at less throttle at a higher RPM. Boiled down to its most basic level Speed = Heat. Regearing won't change that.

 

[ShadowsPapa]

Transmission and additional specs:

https://s3.amazonaws.com/chryslerme...Gladiator_SPECS45esjosaf5fntgd91vsq2ll8dr.pdf

dcmdon,

It appears all Gladiators use the 850RE Eight Speed Overdrive Transmission when combined with the 3.6L Penstar V6.

850RE Gear Ratios: 1st 4.71, 2nd 3.13, 3rd 2.10, 4th 1.67, 5th 1.28, 6th 1.00, 7th 0.84, 8th 0.67

Keep in mind, I was hitting 4500-5000 RPM to maintain 70km/h under that load. Transmission Temps hit 102*C (215*F) (I would be pulling over to cool down if I hit 104*C/220*F), Engine Oil Temp 109*C (228*F) (I would be pulling over to cool down if I hit 121*C/250*F). While I wasn't at the MAX RPM of 6600RPM, I didn't exactly have a lot more in the way of usable RPM's to work with due to the temperatures I was already hitting. As we both agree, the harder you push it, the hotter it gets... I'm curious how you plan to work out the RPM's between the two differential gear ratios? Please show the math as I truly am interested in how this all comes together and I'm sure the others reading this thread are equally as interested.

Tires are the stock 245/75R17's

Cheers,
LittleFish

According to TCI:
the ideal operating temperature for automatic transmission fluid is between 175 and 225 degrees.
At approximately 240 degrees, important additives in automatic transmission fluid (ATF) begin to cook. The result is the formation of varnish inside the transmission.

 

[LittleFish]

According to TCI:
the ideal operating temperature for automatic transmission fluid is between 175 and 225 degrees.
At approximately 240 degrees, important additives in automatic transmission fluid (ATF) begin to cook. The result is the formation of varnish inside the transmission.

Correct. My personal cut off for transmission temp is 104*C/220*F. Exactly how accurate is the temperature gauge on these (or any) vehicles? This isn't a candy thermometer (highly accurate thermometers) so I'd like a little wiggle room to play with. If you look at the temp gauge cluster, the half circle has a wee little red line on the far right. That line is an awful long way away from the indicating temp marker at the 102*C/215*F mark. If that red line was the visual que that a person were basing their max temp safety zone on... they've undoubtedly cooked a tranny!

Hopefully there would be a fail safe that shuts the truck down before that happened. idk

 

[dcmdon]

Correct. My personal cut off for transmission temp is 104*C/220*F. Exactly how accurate is the temperature gauge on these (or any) vehicles? This isn't a candy thermometer (highly accurate thermometers) so I'd like a little wiggle room to play with. If you look at the temp gauge cluster, the half circle has a wee little red line on the far right. That line is an awful long way away from the indicating temp marker at the 102*C/215*F mark. If that red line was the visual que that a person were basing their max temp safety zone on... they've undoubtedly cooked a tranny!

Hopefully there would be a fail safe that shuts the truck down before that happened. idk

The other unknown is that we don't know where the probe is. If its coming out of the oil cooler its going to show cooler than if its just before it goes into the oil cooler.

I'm not saying that its in either place. Just that placement matters.

 

[ShadowsPapa]

The other unknown is that we don't know where the probe is. If its coming out of the oil cooler its going to show cooler than if its just before it goes into the oil cooler.

I'm not saying that its in either place. Just that placement matters.

I would hope these are like where other temp sensors are - and where engine temp sensors have been for decades - just before the fluid is cooled. That's the temperature that the engine or transmission or whatever it is sees that the fluid is at, be it coolant or ATF.
It's going to get slightly more hot where it's working and under pressure and sheer forces are in effect, so if it's sensed from the "pan" that's more of an average.
I'm not sure where the ATF that goes through the cooler is coming from - some older transmissions it came from the torque converter channel, other transmissions it came out from other places before going to the cooler. That matters, too...........

I'd expect the engineers knew what to do, where to put the sensor or sending unit, and where to take the ATF from when sending it through the cooler.

 

[dcmdon]

I have no doubt the engineers know what they are doing and that where the reading is taken from is taken into account when cold start programming is in effect or going into limp mode.

Its just an interesting variable when we look at a number on the dash and don't really know where the temp is being read. 220 in a Pentastar may be the equivalent of 230 in the diesel, for example.

 

[MPMB]

Boiled down to its most basic level Speed = Heat. Regearing won't change that.

Doc Brown says different.

?

 

[ShadowsPapa]

Doc Brown says different.

?

It all boils down to - the faster you go, the slower time goes for you - but when you hit 88 mph, all hell breaks loose.

 

[jeepinmike]

Yeah, $77 bucks for an oil and filter change at home is steep. The P-star can be done for $25. True. But at 6-7 MPG savings you make that money back immediately. And the towing ability... drool... it's amazing. I mean, 24 foot enclosed trailer loaded front to back and it holds 8th gear? Get outta' here...

This thing is a game changer.

But you also have to calculate in the DEF cost and the $4000 premium you paid for the diesel over the gas. It really doesnt save anything unless you tow constantly and plan on keeping it like 100,000 miles. Tow rating is less. Diesel fuel in my area also cost more than gas too. Guess it just boils down to your usage. I do like the sound of the diesel.

 

[LittleFish]

But you also have to calculate in the DEF cost and the $4000 premium you paid for the diesel over the gas. It really doesnt save anything unless you tow constantly and plan on keeping it like 100,000 miles. Tow rating is less. Diesel fuel in my area also cost more than gas too. Guess it just boils down to your usage. I do like the sound of the diesel.

With emissions controls on today's vehicles, diesel powered vehicles seem to have a lot more issues than diesel powered vehicles of the past. Things clog up and it costs $$$ to fix. Or you do delete's of various items (still $$$) and that of course is illegal in most places. As I understand it, city driving tends to not get the vehicle hot enough for the cleaning phase to activate. As such, they clog up! Given that I tend to do substantially more city driving than HWY driving... that's a much bigger issue for me than the +/- $400 Dealer oil changes. Those repair costs are an unknown variable that could easily push my calculated 7-8yr break even to the point where I would never break even. As such, it's simply not the correct vehicle for my needs.

 

[ShadowsPapa]

With emissions controls on today's vehicles, diesel powered vehicles seem to have a lot more issues than diesel powered vehicles of the past. Things clog up and it costs $$$ to fix. Or you do delete's of various items (still $$$) and that of course is illegal in most places. As I understand it, city driving tends to not get the vehicle hot enough for the cleaning phase to activate. As such, they clog up! Given that I tend to do substantially more city driving than HWY driving... that's a much bigger issue for me than the +/- $400 Dealer oil changes. Those repair costs are an unknown variable that could easily push my calculated 7-8yr break even to the point where I would never break even. As such, it's simply not the correct vehicle for my needs.

I don't know about modern diesels in the JT but with my diesel tractors - it was a no-no to use them for work where they would not be run at high RPM or where they were run with little load. You used the gas tractors for running augers, elevators or tasks the diesel wasn't needed for. And when you ran the diesel for cultivating or plowing, you ran in low gears and kept the throttle forward. You didn't run them lower RPM.
Maybe today's small diesels in these are different. But that was my experience.

 

[LittleFish]

I don't know about modern diesels in the JT but with my diesel tractors - it was a no-no to use them for work where they would not be run at high RPM or where they were run with little load. You used the gas tractors for running augers, elevators or tasks the diesel wasn't needed for. And when you ran the diesel for cultivating or plowing, you ran in low gears and kept the throttle forward. You didn't run them lower RPM.
Maybe today's small diesels in these are different. But that was my experience.

Exactly, you ran the Diesel hard to blow out the soot/waste, they're dirty. With all the emissions equipment required on vehicles these days, that waste becomes a problem. Those old diesel pick-ups that ran forever did so because the motor components are beefier (diesel motors run on a higher compression) and they were basically unrestricted as far as emissions were concerned. I have friends with newish 1 ton diesel trucks (mix of city and heavy 5th wheel weekend towing), they are always in the shop for one reason or another. Undeniably, when put to the test for towing, they dominate (provided they're not in the shop, lol). When towing is 5%-10% of the vehicle's use... they clog up. It's the same thing that would have happened to your old tractors if you only used them 5%-10% of the time for their intended purpose.

Here's a pretty good write up on modern diesel motors and emissions equipment.

https://stillrunningstrong.com/car-maintenance/diesel-engine-problems/

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