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Hello and good morning, I recently bought a 33' toy hauler. and I quickly found out that my rig is not set up for towing that kind of weight. wondering if I can get some recommendations for solving this dilemma. truck is all but stock with a juice with attitude programmer. set up is as follows, 01 3500 dually HO 5.9, 6 sp man NV5600,  front axle dana M60 f/ 248mmFBI, rear Dana 80 (hybrid) ( not quite sure what that means ) with 3.55 gear ratio, currently running LT 245/75R17 tire n rims. I work this truck 6 days week as a union pipeline welder, time is precious and I only want to have to do this once. does anyone have experience with the gear vender product? Anyways it time to burn rod, thank you in advance for any and all help.

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  • Owner

Gear ratio (3.55:1) and tire (30.4 inch tall) are perfect. With your 6 speed transmission you are the same as I am for your top two gears. I'm also running 31 inch tires and 3.55 gears. Just I'm running a 5 speed.

 

NV4500 5th Gear -> 0.75 -=- 0.73 <- NV6500 6th Gear

NV4500 4th Gear -> 1:1 -=- 1:1 <- NV5600 5th Gear

 

Gearing and transmission are fine and nothing else needs to be done. As a matter of fact I'm towing a 31' Jayco travel trailer and have nearly the same setup just adding injectors will change the towing ability. Ttime to go up in fuel. Time for some larger injectors maybe a turbo depending on how big of injectors you jump up to.

 

https://mopar1973man.com/garage/vehicle/103-2000-jayco-eagle-296-fbs/

 

Edited by Mopar1973Man
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  • Staff

Some RV275 injectors and a adjustable boost elbow would be a good start. You will need boost and pyro gauges if you don't have them already. It doesn't take much to get a little extra hp out of these motors. 

 

Personally I would hate 3.55's and the NV5600 for towing any weight on interstates, but I run a taller tire. My 3.73's and my NV5600 suck at 60-70 in anything more than a 3% grade. It does tow great at 75 thou :doh:. With 245/75R17's being just over 30" on the rolling diameter it's quite as horrible thou, and actually spins a few rpms more at 65 than I do with 245/70R19.5's and 3.73's. 2000 rpms will get you 70 and it gets me 71. I prefer to be above 2000 rpms while towing heavy on grades which is why 60-70 mph is the worst to cruise at for me. 72-73 and everything runs great! 

 

I have contemplated the swap to 4.10's many times but I don't tow on the interstate as often as I do on highways and 5th gear with 3.73's is a great highway hill pulling gear. 

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My truck works just fine and is set up much like yours, minus the 2 extra tires. Gauges and a little bigger injectors will make the truck and you happy. The RV 275's are a great addition and fairly economical. Should see a little uptick in mpg with them. 

 

How much does the trailer weigh? I gross out around 23k GCW.

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  The Gear Vender over/under drive is all most identical to the British made Laycock overdrive used in M G, Triumph, and Volvo motor cars.  Over the years I've had the pleasure of rebuilding/replacing this type of overdrive. 

   The biggest problem I found was the bore for the sleeve piston wearing.  The sleeve piston is made from hard steel and the bores are machined into the softer metal of the housing.   When the pressurized fluid (400-600psi depending on engine type, and 650-700psi for Gear Vender) is routed to the bores it will bypass the o-ring seal on the piston and the cone clutch will not engage. 

  I see that Gear Vender sell them for $3700 plus installation.  You can buy a lot of performance upgrades for that kind of money. 

594f1d551fe40_GKN_overdrives_cut2.jpg.5c30026f9b86a5eac481b6293e3370ea.jpg

 

 

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On ‎6‎/‎24‎/‎2017 at 7:29 AM, Mopar1973Man said:

Gear ratio (3.55:1) and tire (30.4 inch tall) are perfect. With your 6 speed transmission you are the same as I am for your top two gears. I'm also running 31 inch tires and 3.55 gears. Just I'm running a 5 speed.

 

NV4500 5th Gear -> 0.75 -=- 0.73 <- NV6500 6th Gear

NV4500 4th Gear -> 1:1 -=- 1:1 <- NV5600 5th Gear

 

Gearing and transmission are fine and nothing else needs to be done. As a matter of fact I'm towing a 31' Jayco travel trailer and have nearly the same setup just adding injectors will change the towing ability. Ttime to go up in fuel. Time for some larger injectors maybe a turbo depending on how big of injectors you jump up to.

 

https://mopar1973man.com/garage/vehicle/103-2000-jayco-eagle-296-fbs/

 

 

WIN_20170625_05_48_18_Pro_LI.jpg

WIN_20170625_05_47_53_Pro_LI.jpg

WIN_20170625_05_48_35_Pro_LI.jpg

WIN_20170625_05_48_46_Pro_LI.jpg

morning, my data is limited as well as coverage, want u to c this, pg 1A.

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  • Owner

I know the 245/75R17 is not factory. They are about 0.1" to 0.3" smaller depending and what you compare them too. This makes the rev per mile for your tires 660 Rev/mile. This should have the effect of smaller final gears making towing easier. My 235/85 R16 are taller and narrower or 265/75 R16 are taller and wider. Typically the stock size is 245/75 R16 for 2WD trucks and 265/75 R16 for 4WD. This is only rule of thumb... I've seen 2WD truck sold with 265/75 R16 as well.

 

https://tiresize.com/calculator/

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I thought 235/85R16 was stock on 4wd DRW's for 2nd gens ? It looks like page 3 posted above says that too. 

 

245/75R17 is only about 3-4 rev/mile slower than 235/85R16, so it may be hard to even notice. 

 

 

It looks like that calculator uses static diameter to get rev/mile and not rolling diameter. It's generally less than 10 rev/mile difference but still worth noting. Most tire manufacturers post rev/mile data based on rolling diameter. 

 

Oddly enough the 245/75R17 comes in accurate, but none of the others I tired did. They must run a little tall for their size. 

Edited by AH64ID
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  • Owner
12 minutes ago, AH64ID said:

I thought 235/85R16 was stock on 4wd DRW's for 2nd gens ?

 

3500 series yes... 2500 was 265's for 4WD I'm sure of. As for the 235's the only series I knew for sure was the 3500. This goes back to the argument of the information posted in the door jam about tire size and information. Which 90% of the time is untrue. Even both of my truck post wrong information. My 2002 states 245/75 R16 was stock (wrong it was manufactured with 265/75 R16) then my 1996 states 215/75 R16 was stock (it was manufactured with 235/85 R16). So as for the 245's I think that was more of 2WD series tire personally I've never seen it on any tire as of yet.

 

Still in all getting back to the OP there should be any issue towing with his combo. Might just have to add more fuel and it would pull better.

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Thought so. The OP has a DRW so no need to compare him to a stock 265. 

 

Interesitng on your door stickers. I've never seen one that didn't show what the vehicle came off the assembly line with. I have seen dealers change the tires quite often, but that's not the mfgrs fault. Is this 90% error fact or opinion? 

 

In all the vehicles I've bought, or my family has bought, over the last 25 years I've yet to see one with the wrong OEM tire size on it. I'm having a really hard time believing there is an actual 90% error rate. 

Edited by AH64ID
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