confused trans

[cb1987]

there was another thread (probly several) that touched on this same subject but i couldnt seem to find it (found it last night but forgot where it was). so im asking here. i dont have photos yet but over the weekend i installed a bunch of thuren parts ( front and rear springs , fox , trac bar etc) along with some 37x13.5r 17 tires and wheels (stock 2017 diff gears for now but likely 5.13 in the future). i almost dont recognize the truck any more. drives and handles way different. new hum from the tires. other new noises that werent there before. as expected ,it seems the trans is a bit confused sometimes. it lugs the engine wich causes a groaning sound when lightly accelerating. my car does the same thing when its in OD and the converter is locked at slow speeds around 40mph. anyways im also hearing what sounds like a engine braking noise in 5th and 6th if i let off the pedal at highway speeds and coast. at fast highway speed have you guys also heard what sounds like engine braking sounds ?

[SimonandSimonBeast]

Did you program the truck for the new tire diameter?

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[cb1987]

no i havent done anything. its a stock 2017 up until this point. i did have 35s previously but the truck did fine with no odd behavior or noises. these new 37s really took the wind out of its sails and created all kinds of strange noises. like i said, groaning sounds from lugging and what seems to be a engine braking sound while decelerating from 75mph to about 55mph. have you guys also heard the engine braking sound ?

[Oilbrnr]

Did you remove the exhaust resonator at some prior point? If so you might be hearing the MDS kicking in more when you let off the throttle at higher speed. Do RPMs go up like if is downshifting from 6-5?

[TankerZak]

Program the truck for the tire size. Really helps. There is also a transmission relearn sequence that can be triggered but wait until you reprogram the tire size.

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[cb1987]

Did you remove the exhaust resonator at some prior point? If so you might be hearing the MDS kicking in more when you let off the throttle at higher speed. Do RPMs go up like if is downshifting from 6-5?

no the exhaust is stock and new condition. i didnt even consider mds but maybe thats whats making the high speed decel engine brake noise. it also changes and seems to go away if i manually down shift. the noise is quit audible now for some reason. i dont ever recall hearing it with the 35s. i still have the 35s so i could always throw them on for a quick test drive .

i havent noticed (ill listen close next time) rpm going up in 5-6 but its doing it in 4th. rpm goes up like its down shifting but it doesnt shift down. i thought it was shifting down but the gear indicator never changed. i didnt realuze these bigger tires really screw with the electronics

[cb1987]

Program the truck for the tire size. Really helps. There is also a transmission relearn sequence that can be triggered but wait until you reprogram the tire size.

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im not familiar with programing for tire size. got any info and what it does ?

[DamageWagon]

You can program tire size with either an AEV ProCal or the AlfaOBD app on an android device.

What sounds are you hearing from your suspension??? Is this all engine and tire noise or is this suspension noise? That system should be silent.

[SimonandSimonBeast]

Think about it like this. You were already ~2 inches over stock diameter and now a total 4 inches over stock nominally with 37s. Everything is connected electronically these days. Your trucks computer needs to know how fast the tires are really spinning. The tire size change throws that off. This effects shift points, speedometer, odometer, electronic stability control (ESC), etc. Get it corrected with one of the items DamageWagon recommended. I own both now. Either will do the job, Alpha can do more, but takes a little to figure out. Once that is corrected, then see how it feels. Might still feel a little laggy with the 4.10 gears, but I think a lot of folks on here run that way happily.

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[Bill2014]

In the mean time, put it in Tow/Haul mode which will help with the shifting and lock out 6th. 5th gear with 37's will get you closer to 6th on 33's

[cb1987]

You can program tire size with either an AEV ProCal or the AlfaOBD app on an android device.

What sounds are you hearing from your suspension??? Is this all engine and tire noise or is this suspension noise? That system should be silent.

the suspension is fine , although it feels like a marshmellow now but thats not a bad thing really. the new noises seem to be engine related because the trans is confused with the larger tires. ill look into the alfa and report back with many questions im sure. in the mean time ill use tow haul mode i guess. does anyone know the 6th gear rpm at 75mph with 5.13 and 37s ? eventually ill regear im sure. right now 5th seems to be a good cruising gear as 6th is useless

[Bill2014]

That's a simple - straight forward calculation...

75mph / 60minutes per hour * 12inches per foot * 5280feet per mile / 37inch diameter / pi() * 5.13gear ratio * 0.62sixth ratio = 2,167rpm

[PWJouster]

some questions that we glaze over but drastically influence tire performance, and rolling resistance....

PSI of all four tires?

did you come from 12 inch wide or 13 inch wide treads with the 35s?
in fact what brand and tire did you come from and go to?

did you get an alignment whatsoever?


shift the column shifter to 6th gear everytime you get in the truck to lockout MDS and create a more non variable environment for testing
your sounds and transmission concerns are MDS and the fact you havent programmed your tire size.
take these steps and report back.

[EasyDoesIt]

I'm running 5.13s and 37s on my 2018. Running just over 2100rpms at 75mph.

[KevinABQ]

You can program tire size with either an AEV ProCal or the AlfaOBD app on an android device.

Or an hour of labor at the dealer.

But they can’t reprogram the TPMS. However TPMS reprogram is easy, tire size adjustment is a bit more complex.

If you have no speedometer and ABS alarms going off and all sorts of weird issues you did the tires size wrong.

[waldo]

Good luck.

My 3 year experience with the 66 RFE in my 16 was not good and that was with stock tires and gearing.

[cb1987]

some questions that we glaze over but drastically influence tire performance, and rolling resistance....

PSI of all four tires?

did you come from 12 inch wide or 13 inch wide treads with the 35s?
in fact what brand and tire did you come from and go to?

did you get an alignment whatsoever?


shift the column shifter to 6th gear everytime you get in the truck to lockout MDS and create a more non variable environment for testing
your sounds and transmission concerns are MDS and the fact you havent programmed your tire size.
take these steps and report back.

i reset my tpms thresh hold a long time ago to 35psi i think. using 40psi in the 37s now. havent chalk tested yet but probly this weekend. it drives nice though. had a slight pull to the right but im not sure if it was new tires or maybe the new king ss. ill dig into it this weekend

had 35x12.5r18 razr. advertised 13.2 wide . theyre probly one of the widest 12.5 ive personally ever seen. 37s are buckshot 37x13.5r17 advertised 13.4 wide if i recall. load e with 65psi max

truck was put on alignment rack when it was new ,just for future reference. had slight toe in. caster 5* driver 5.3* passenger. had chassis lean so i put both sides at 5. truck drove like a dream. before installing the thuren springs i checked axle angle via bump stop pad so i can put it back to where it was for 5*. thats on my to do list for this weekend. ill report back when i get it dialed in a bit more

[cb1987]

I'm running 5.13s and 37s on my 2018. Running just over 2100rpms at 75mph.

sounds about the same as 35s with 4.10. was hoping 5.13 would be closer to 2500rpm. oh well. what shops are knowledgable in the wagon axles that can do the 5.13 swap ? im about 2.5hrs from salt lake. 4hr from cheyenne. 6hr from denver

[Bill2014]

I'm running 5.13s and 37s on my 2018. Running just over 2100rpms at 75mph.

sounds about the same as 35s with 4.10. was hoping 5.13 would be closer to 2500rpm. oh well. what shops are knowledgable in the wagon axles that can do the 5.13 swap ? im about 2.5hrs from salt lake. 4hr from cheyenne. 6hr from denver

You can always lock out 6th with the shift selector.
5th gear @.82 is still an overdrive but that would shoot you well above 2500rpm at 75mph

[ramv]

I'm running 5.13s and 37s on my 2018. Running just over 2100rpms at 75mph.

sounds about the same as 35s with 4.10. was hoping 5.13 would be closer to 2500rpm. oh well. what shops are knowledgable in the wagon axles that can do the 5.13 swap ? im about 2.5hrs from salt lake. 4hr from cheyenne. 6hr from denver

The drive train shop in Rock Springs (Six States I think) did my '01 back in the day. No complaints, probably the best axle work I had done ever. I assume you are near...

[cb1987]

I'm running 5.13s and 37s on my 2018. Running just over 2100rpms at 75mph.

sounds about the same as 35s with 4.10. was hoping 5.13 would be closer to 2500rpm. oh well. what shops are knowledgable in the wagon axles that can do the 5.13 swap ? im about 2.5hrs from salt lake. 4hr from cheyenne. 6hr from denver

The drive train shop in Rock Springs (Six States I think) did my '01 back in the day. No complaints, probably the best axle work I had done ever. I assume you are near...

i talked with that place just today but they said their diff rebuild operations have drastically been scaled back and mostly just do drivelines now. they dont even have a vehicle lift anymore. the dealer has four master techs and said theyre willing to do it. i just dont know how much diff experience they have but i guess with a service manual and proper tools it shouldnt be to difficult. im just not sure they have a press and puller for bearings or tool for checking pinion depth etc. im going there in person probly saturday and see for myself if theyre capable of doing the job. on the other hand im certainly not opposed to driving a few hundred miles to a well qaulified 4x4 shop. there has to be some decent shops in ut or co with all the four wheeling in those areas. ill keep searching and making phone calls.

[ramv]

None of the places in Denver I went to I would go back, I would imagine SLC would have some decent shops. I'm not sure if Off Road Designs in Carbondale would do just some diffs but good people and good work from my experience.

[Ducky's Dad]

...doing it in 4th. rpm goes up like its down shifting but it doesnt shift down.

Seems like that might be the torque converter unlocking under load in 4th because of the big tires and and high gearing. My '05 with 4.56s doesn't have that trans, so no real point of comparison.

[NickTF]

Program the truck for the tire size. Really helps. There is also a transmission relearn sequence that can be triggered but wait until you reprogram the tire size.

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Is the relearn something that is more complicated than simply disconnecting the battery for 10 minutes and reconnecting? Does disconnecting the battery result in pro-cal uploads being erased and default back to OEM parameters?