Diff switch from 3.55 to 4.10

[Mopar1973Man]

Either way manual or automatic both transmission basically have the same top two gears. 

[Evan]

At 65mph 3rd gear locked I'm at 2400rpm.

 

Being able run 3rd to 65 makes the range between 3rd and fourth gear very usable and adjustable between roads and driving conditions.

 

I'd imagine small tires and 4.10s st times may feel like a one speed tranny.

 

The more we talk about this the less I'd want 4.10 and small tires.

 

I did get my 65mph reading with 285x70x17s wich I just mounted wich are slightly shorter than my 285x75x17s

Picked up a second set of aluminum geniii wheels with kinda decent cooper sst pro tires on them.  

 

I wonder if mike can make it to Ontario without shifting gears. Lol kidding. He does run on the river and mtn rds where  speed is often reduced

 

Normally run smarty on 6 or 7. Though right now its on 8

[Mopar1973Man]

21 minutes ago, Evan said:

At 65mph 3rd gear locked I'm at 2400rpm.

Nope ratio is wrong. 66 MPH in top gear (5th at 0.75:1)  I'm twisting 2,000 RPM perfect. Difference is I'm doing better than 20 MPG which I doubt your getting with 35-inch tires. 

 

22 hours ago, Evan said:

With 35s and 47re 3.55s it appears I can match Mike's manual transmissions rpm

Nope. Not in top gear you not. I'm pretty sure not in MPG either. 

 

65 MPH is ~1980 RPM in 5th gear making roughly 20-22 MPG.

55 MPH is ~1760 RPM in 5th gear making roughly 23-25 MPG.

 

 

[Evan]

I never said I'm getting 20. I have got better then 20 but not while packing 2k om the truck.

I'm getting 17-18 depending on conditions of each tank checked. Towing alittle mostly empty but always 9400lbs.

 

3rd gear is perfect for slow rd towing 65 and under. I definitely cant fo 80 in 3rd. 

 

I'm sure my ratios of my mpg is off but there is no deciding that it's working very well for me. 

I wouldnt doubt your numbers are off to. I'm sure I could get in your truck and like how it's set up just fine. Only thing I wouldnt like is spinning so many Rs om the freeway . Well that and shifting gear. I love getting out of our big truck and just pushing the pedal down in my pickup.

[Mopar1973Man]

9 hours ago, Evan said:

3rd gear is perfect for slow rd towing 65 and under. I definitely cant fo 80 in 3rd. 

I used to be able to tow at 55 MPH in 4th (1:1 direct). No longer with the change of tire by 1 inch. All done in top gear now. 

 

So I've gotta ask what is your MPG logs looking like? 

[Evan]

Been virtually no change with smarty. Or settings  but I'm not able to run consistent. This tank I hauled 10k a few times in stop and go traffic last tank I didnt nit still got 500 on 28gallons

 

500 plus a few miles for 27-28 gallons.

 

I haven't measured the tires I have on. Smarty is set at 33" . These should measure 31 32 just haven't done it yet.

 

I'm burning a tank every  3 days so I should be more on top of it with real numbers.

 

It's not super important though if I go empty at 400 miles I'll no something's up

[Mopar1973Man]

Suggestion...

https://www.simplyauto.app/

 

Helps with keeping good fuel logs. 

 

 

[wagntagn]

So on the weekend I installed my 33" winter tires on the truck and pulled my buddy's fifthwheel 12000 lbs no problem outside temp 28 the egt's  went to 1200 pulling  on our longest steepest hill in our area,the pics are cruising on a flat everything looks good I'll probably keep my 3.55 and step down from my 35" tires to 33".

[Evan]

That's awesome. 

 

I dont have alot of time,  logging fuel is not high on priority. 

Though logging dirt loads is.

[Mopar1973Man]

I've been logging my fuel way back 20k miles. I've still got old spread sheets and my original fuel log book. This is how I figure out what mods and such produce the best gains.

[Evan]

I'm what those but dyno mod feelers. Hmm that didn't sound right

[Dieselfuture]

18 minutes ago, Evan said:

I'm what those but dyno mod feelers. Hmm that didn't sound right

It happens 

[Mopar1973Man]

Everything I've done is based on test data and making sound judgement calls on parts. My budget is a extremely tight and poor choices can result in wasted money.

 

[Evan]

I've found sometimes choices sound or not often results in wasted money

[Mopar1973Man]

Kind of how a wasted a great 1972 Dodge Power Wagon pickup with oversized tires and lift kit. Broke the front wheel joints 3 different times. Damaged wheel bearings. Tore up a drivershaft. Wiped out a few clutches, Wrong final gearing... End up trading that truck in and get the 2002 Dodge Cummins. Took a huge hit for trade in value for the trashed front axle you can't get parts for any longer. 

[wagntagn]

I picked up new tires 31” my truck pulls the fifth wheel no problem I can coast on the highway at 1600 rpm in overdrive I just press the switch when climbing long steep hills I still go up to 1200 egt’s when pushing the truck to maintain my speed that should be ok??

[Evan]

How in world are you at 1600 rpms with 31s

 

1200 deg is what I try not to go over when pulling a hill.  I'll pull a hill in the 12s with no worries.  More than that I start to worry 

 

[Bullet]

2 minutes ago, Evan said:

How in world are you at 1600 rpms with 31s

Coasting @ <60 maybe.  I'm currently running true size 33.20" tires with speedo GPS calibrated dead-on with the Smarty and 65 mph gives me 1625rpm...60 mph @ 1500, 70 @ 1750, 80 @ 2000, 100 @ 2500, starts burying the needle @ 3000.

[Marcus2000monster]

I have a used set of 4:10 ring and pinion. I’d sell them for a good price. I just did the same thing but the other way around in my old truck. It’s not very hard. 

[wagntagn]

At 1600 rpm I’m cruising 55 mph I climb the hills no problem when I cancel od it will rev roughly 2200 if I floor it it will gain speed but egt’s climbs to 1200 just keeping an eye on egt’s,I’m at setting 5 on my Smarty where should I be set + timing or not??

Marcus are in Canada?