New 4.30 Gears for 2007.5 DRW with 19.5"

[CUMMINZ]

Well I have been talking about this change since we began our 14,000 mile trip across the country with our 17k fifth wheel. A while before the trip I changed my gears from factory 4.10s to 3.73s for the trip and the rest of our travels. We figured out pretty quick how much of a mistake it was to switch. Through advice from other posters here I found out that Diesel Power Products sold a wide range of gears and I ordered a set of front/rear gears and installation kit. I had my local RAM dealer swap them out this week. I test drove it this afternoon and wow what a difference. As you can see I now turn 2000rpms at 70mph and that is exactly what I wanted. One interesting thing: the rear ring gear/pinion was AAM 11.5". The new rear gear is late model RAM with 11.8" ring gear.

RPMs and Speed with 19.5s and 3.73s

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Photo below is at 70mph with 4.30s
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Pinion on right is 4.30 and larger on left is 3.73

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Ring gear on top is thinner 3.73 and thicker on bottom is 4.30

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[kthaxton]

I don't recall....but was your change to 3.73 in effort to save fuel? If so, that likely would have taken many years to pay itself back......and now you've bought two sets of gears....yikes! Did somebody suggest this to you?

 

[CUMMINZ]

I don't recall....but was your change to 3.73 in effort to save fuel? If so, that likely would have taken many years to pay itself back......and now you've bought two sets of gears....yikes! Did somebody suggest this to you?

I really expected a decrease in fuel. My wife just retired and expected we would put 50k miles more on the truck. From the start I have bragged about the 4.10s with the 6 speed. It was just one of those mistakes in life. Recently after towing the rv for 14k in nearly 5th gear showed me the mistake.

 

[CUMMINZ]

I don't recall....but was your change to 3.73 in effort to save fuel? If so, that likely would have taken many years to pay itself back......and now you've bought two sets of gears....yikes! Did somebody suggest this to you?

I really expected a decrease in fuel. My wife just retired and expected we would put 50k miles more on the truck. From the start I have bragged about the 4.10s with the 6 speed. It was just one of those mistakes in life. Recently after towing the rv for 14k in nearly 5th gear showed me the mistake.

 

[BigPapa]

I remember your thread about the 4:10/3.73 swap but I guess I never noticed the 19.5 part. Yeah, the 3:73 was a bad idea. Glad you got it where you want it.

 

[kthaxton]

Out of curiosity......
So I see mention of 19.5's a lot. However that doesn't tell me the tire diameter which is really the measurement matters when considering gear ratios. Is there only one tire size for a 19.5 wheel? Am I missing something?

 

[CUMMINZ]

Out of curiosity......
So I see mention of 19.5's a lot. However that doesn't tell me the tire diameter which is really the measurement matters when considering gear ratios. Is there only one tire size for a 19.5 wheel? Am I missing something?

If you lookup Rickson Wheel website under tire section they show individual tire heights. 225x19.5 are just a little taller than dually size 17" tires. I am running 245x19.5s which are 33.4"s tall. 225, 245,265 & 285s are available in 19.5s.

 

[BigPapa]

The LT245/70R19.5's are roughly 1.5" taller than stock and they weigh 50-60 pounds more than stock.

 

[CUMMINZ]

These are not 19.5s but factory 15s and a replacement to a 16" that I put on an old RV of mine. Does show a difference.

 

[AH64ID]

Looking at DPP's website they have 11.5 and 11.8 gears in 4.30. The verbage makes it look like 11.8's shouldn't be used in the 11.5".

Did they explain why they were selling 11.8's for your 11.5 axle?

 

[CUMMINZ]

Looking at DPP's website they have 11.5 and 11.8 gears in 4.30. The verbage makes it look like 11.8's shouldn't be used in the 11.5".

Did they explain why they were selling 11.8's for your 11.5 axle?

When we opened box at home and saw the rear gear marked 11.8" I called DPP and they called manufacturer. Manufacturer said there was NO problem. Go figure.

 

[AH64ID]

When we opened box at home and saw the rear gear marked 11.8" I called DPP and they called manufacturer. Manufacturer said there was NO problem. Go figure.

Good deal!

I have almost talked myself into 4.10's in the spring and like the idea of 11.8" R&P.

 

[CUMMINZ]

Traveled to Charlotte this morning and hooked up to our CC Champagne and towed it home. What a difference with the new 4.30 gears.

I reset overhead 8-10 times during the trip. My overhead for the most part is 1mpg fast. I see NO degradation in towing mileage. I did notice EGTs seemed to stay below 1000 degrees. Much better than before. transmission did great and stayed in 6th gear.

 

[AH64ID]

Is the gear breakin on aftermarket gears similar to OEM gears?

 

[CUMMINZ]

Is the gear breakin on aftermarket gears similar to OEM gears?

I have not read any requirements.. I have driven the truck for 6-7 weeks mty.... I now turn 2k at 70.

 

[AH64ID]

I have not read any requirements.. I have driven the truck for 6-7 weeks mty.... I now turn 2k at 70.

I did a search and found the Nitro break-in procedure.

BREAK-IN PROCEDURE:
In order to prevent damage to differential components it is essential to follow the break-in procedure after installation of a new ring &
pinion. New ring & pinions will generate more heat initially after installation and can cause gear oil to break down, leading to premature
failure. On your first drive, stop after the first 15 or 20 miles and let the differential cool for 20-25 minutes before proceeding. Drive conservatively
for the first 500 miles following installation (avoid hard acceleration & towing). After completing standard break-in, tow for very
short distances (less than 15 miles) and let the differential cool before continuing during the first 45 towing miles. Change the gear oil after
the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new ring & pinion.
Premature overloading/overheating will cause gear oil to breakdown, and may result in parts failure.

 

[CUMMINZ]

I did a search and found the Nitro break-in procedure.

BREAK-IN PROCEDURE:
In order to prevent damage to differential components it is essential to follow the break-in procedure after installation of a new ring &
pinion. New ring & pinions will generate more heat initially after installation and can cause gear oil to break down, leading to premature
failure. On your first drive, stop after the first 15 or 20 miles and let the differential cool for 20-25 minutes before proceeding. Drive conservatively
for the first 500 miles following installation (avoid hard acceleration & towing). After completing standard break-in, tow for very
short distances (less than 15 miles) and let the differential cool before continuing during the first 45 towing miles. Change the gear oil after
the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new ring & pinion.
Premature overloading/overheating will cause gear oil to breakdown, and may result in parts failure.

64, Thanks for that info.

 

[mpaulson]

Out of curiosity, did you have the speedo corrected with the tire change?

 

[CUMMINZ]

Out of curiosity, did you have the speedo corrected with the tire change?

My Smarty did the correction and speed checked by 2 GPSs and an app on cell phone.

 

[CUMMINZ]

No gear hunting

I went back and reread this thread. I made a statement on the post with the overhead pic and I typed "transmission wanted to dnshift from 6th gears. That was incorrect. Spell check must have changed some words. Just the opposite. The transmission did a great job staying in high gear. I am running the Smarty on 90hp, #4 on tq and #4 on timing. Had plenty power.