Engine/Transmission (1998.5 - 2002) 3.55 to 4.10

[pcarlson]

Any recommendations on who is the best gear supplier thru? I want the extra grunt for towing, not concerned with the mileage drop, and I am looking to swap as soon as I can get the parts and an installer.

 

[rweis]

I think I remember that you can go 3. 54 to 3. 93? without changing carrier bearings. Else to 4. 10 you have to change the carrier bearings.



Someone else chime in here and help me remember.



Bob Weis

 

[TradedV-10foraCummins]

I looked into it not too long ago. You can go from 3. 54 to 3. 73 without changing the carrier.

 

[pcarlson]

Thanks for the info, I'm not concerned about changing the carrier, just that it will add more to the cost. I'd replace the bearings anyway just to keep things tight.



Any recomendations on who to buy the parts from? i. e. ring and pinnion, carrier, bearings, etc.

 

[macdaddy]

Thanks for the info, I'm not concerned about changing the carrier, just that it will add more to the cost. I'd replace the bearings anyway just to keep things tight.



Any recomendations on who to buy the parts from? i. e. ring and pinnion, carrier, bearings, etc.

Do a search for Randy's Ring and Pinion their in the Edmonds Wa area near Seattle. Sorry I tried to find the number I'll keep looking.



Mac

 

[monkfarm]

How hard is that to do? (to change out the gears) (I'd like to put a (somewhere around a ) 3. 10 to 3. 25 in mine.

 

[Beast2B]

monkfarm, it's QUITE involved. why not go to a taller tire to change the effective ratio?

Randy's Ring & Pinion 1-888-324-9096

Check out National Drivetrain, they usually have some good blow out prices.

I was told that up to 3. 91 you can use your carriers, 4. 10 and higher (numerically) requires a different carrier. I have heard of gears that use the stock carrier to go up to 4. 10, but it seems that the special thickness ring gear may compromise performance... just my 2 cents

 

[pcarlson]

Mac/Beast2B,



Thanks for the number, I'll give them a call. I plan on having a drivetrain shop do the install since it's quite involved and I want the setting correct so I don't end up ruining the gears.



Thanks,

 

[pcarlson]

I just got off the phone with Randy's Ring and Pinion, and I ordered the gears (Yukon Gears) and install kits. The carrier is fine, they said 4. 10 is the cuttoff on these axles, Dana 60/70. They said some Chrysler axles have 3. 92 as the cuttoff. Now I will just wait for the parts and track down an installer.



I believe I need the PCM reprogramed for the ABS with the new gears, is this correct?

 

[Beast2B]

Yeah, the dealer can change the ratio in the computer. Some of the aftermarket programmers allow this also. You can also correct for non-stock tire size if necessary at the same time.

 

[JBlock]

Beast2B is correct



My superchip programer allows for tire size correction, the pickup for the speedo is located after the gears so changing to 4:10 should not effect the speedo, I not sure on the ATS. but I would venture it will be ok too. Only draw back is you need to use a one of the performance setting programs access the speedo correction. I not sure if you can recalibrate then go back to stock.

 

[Beast2B]

The vss speed sensor is on the ring gear in the rear diff housing, isn't it? It doesn't matter where the sensor is located, if the speedo/odo is reading revolutions of the axle to calculate the distance travelled and you change the distance you travel on each revolution (larger or smaller tires or gear ratio change), you have to correct the computer to get the right speed/distance on your dash displays.

I don't know if the Superchips programmers offer it, but the factory DRB gives you only 245/75-16 and 265/75-16 tire sizes, but you can access another screen to input the revs per mile of whatever tire you have. That's how I corrected my speedo for 37" tires.

 

[pcarlson]

So if I leave the stock 265's and just change the ratio to 4. 10's is there a change in the PCM?



Beast2B,



I do believe the speed pickup is on the rear ring gear sounding ring. If that is the case I would not think I would need a speedo correction as it would read the correct rev's off the axle and the tire rev's per mile is already correct as it is the stock tire size. Also, I do believe the ABS uses the same pickup. Am I thinking right here? I would need to recalibrate only if I changed to a different tire diameter as that would throw it off.

 

[Beast2B]

I do believe you're correct. The only option I recall in the DRB tool was if you were going to an axle besides the Dana.

 

[pcarlson]

All Done!!!

Got the truck back today. All seems well no leaks that I can see. They talked me out of the 4. 10 and said that I would be happier with the 3. 73 ratio. So that is what I did and 3. 73's is what she's spinning on. They thought the 4. 10's might be just alittle to much rpm for the cummins (even thought it's a factory option) and would hurt mileage and they said the 3. 73 was a great compromise between towing power and mileage. Their logic sounds about right since that is exactly what the 03+ Rams are using. We shall see how we do when I hook up the 5er.



The only problem with the install kit was the pinion seals were wrong but the dealer had them and they didn't charge me to much for them. They showed me the old and new seals and sure enough they weren't going to work.



I had the dealer in Iowa where I work do all the work for me as the tech that does the axle work is an avid racer and does alot of axle work for the local guys at the track so i didn't have any doubt about his expetise on doing this. Plus he is also their diesel tech!!! The service manager was all grines when I went to pick it up as he had taken it for a test drive. Glad he could appreciate the power with out being out to get me.

 

[monkfarm]

Beast2be (Reply)

Beast2be: Ya, you are right on top of it. I plan to put 22. 5s and then I certainly won't need taller gears. But I haven't ordered anything yet, and I'm still exploring the options

 

[Beast2B]

always better to procrastinate for a while, then do it once! (especially good when the funds aren't hanging in front of you!)

 

[SnoKing]

Well I would have stayed with the 4:10 decision. I tow a 2005 Cardinal 29WBLX at 11,250 lbs. I stay in OD at 63 MPH at around 2000 RPM's and it tows sweet. With my DTT and engine mods I hardly ever have to come out of OD towing now on the freeway. You are going to have to tow a little faster to stay in the 2000 RPM sweet spot, or be out of OD more. I am getting around 12 MPG towing BTW and high teens bobtail. SNOKING

 

[pcarlson]

SNOKING,



I played with that decision for about two days before I changed. I guess the one factor that came into play was when I was unloaded and fuel mileage as I don't really worry about mileage towing. My Cardinal 33TS tipped the scale at 11,894 and the 3. 55's did fine pulling at 65 on the interstate as it didn't have to shift down to pull but where I am at now is fairly flat and if I venture out west I wanted a little extra grunt if you will for the bigger hills.



I looked at gear calculators where your at 1955rpm at 65, I will be at 1778rpm and I figured this wouldn't be to much of a drop off from the 4. 1 but a got bump from the 3. 55's. With the cost of gears and install I definitely wanted it to be right for me the first time.



First impressions so far is I have to hold the brake a little harder or the transmission will pull through the brake and my mileage seems up just a little. But to early to tell about mileage without more data.

 

[Regcabguy]

I've contemplated going to 3. 73's for quite sometime now. My truck came with 245's and I remember how quick it was even before bombing and the larger tires and camper. The 3. 73's would restore the factory ratio and keep you in that sweet spot without having your foot in it. I got a bid of $1300. 00 for both axles at Pro Gear here in San Diego when mileage was lower. Probably more now with additional parts necessary.