Gear ratio questionI have a 1996 Dodge Ram 2500HD SLT (2 wheel drive) with the Cummin - Dodge Diesel - Diesel Truck Resource Forums



12 Valve Engine and Drivetrain Talk about the 12V engine and drivetrain here. This is for 1994-1998.5 engine and drivetrain discussion only.

Gear ratio questionI have a 1996 Dodge Ram 2500HD SLT (2 wheel drive) with the Cummin

Reply
 
 
 
Thread Tools Search this Thread
Old 04-25-2014, 10:21 PM   #1  
Registered User
Thread Starter
 
Alfdude1's Avatar
 
Join Date: Oct 2011
Location: Anaheim, CA
Posts: 30
Gear ratio questionI have a 1996 Dodge Ram 2500HD SLT (2 wheel drive) with the Cummin

I have a 1996 Dodge Ram 2500HD SLT (2 wheel drive) with the Cummins turbo diesel and 47RE automatic transmission with a DTT valve body. The engine has been modified to produce approximately 325 hp and 800 ft/lbs. Can you tell me at approximately what RPM does the torque converter lock up? I ask this because I am looking at changing out the differential gears from 410 to 354 and want to make sure that I am not turning too low of an RPM that can cause damage to the transmission or other drive line components.

Currently, I have replaced the 235/70 stock tires with 285/70 tires. With the 410 gears here are the RPMs I turn in OD with torque converter lockup:

1,500 rpm - 48 mph
1,750 rpm - 56 mph
2,000 rpm - 66 mph
2,250 rpm - 76 mph

I have been told that the gear replacement will drop my RPMs by about 400 RPM. Will that be too low of an operating RPM? I am looking to improve my fuel mileage on the highway at 60 mph and above.

In your honest opinion, would this be a beneficial or recommended swap?

Thank you for your time,
Mike
Alfdude1 is offline   Reply With Quote
Old 04-27-2014, 12:57 AM   #2  
Registered User
 
Join Date: Apr 2003
Posts: 819
I run a nv5600 now...which is a slightly higher (lower numerically) od than the 4500....with 3.54 gears....and recently went to 19.5's and a 33.4 inch tall tire.

My mileage went up....My truck is highly modded thou. But the higher gear lowered the cruising boost....I cruise down the road (towing 6k or more) at 1600 to 1900.....and with the lower boost the afc is not adding as much fuel. I think Im going to ad a air valve and second boost gauge in the afc line to taylor the afc signal cruising.....

If you dont make enough power.....the higher gear could make it go the other way, i think, just depends on how you use your rig.
1320 is offline   Reply With Quote
Old 04-27-2014, 12:39 PM   #3  
Administrator
 
Join Date: Jan 2007
Location: Streator Illinois
Posts: 8,317
Mine is all stock except for 235-85 tires ( 33") and I run about 1750 at 60-62 MPH, which for my truck is optimal.

From what you posted, unless you are running very heavy in the hills, I think the 3.54's would be a good fit.

Since you are a D70, why not just get a whole rear instead of changing gears?
patdaly is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Fair price for a 1996 Dodge Ram 2500 SLT Club Cab phillychoppin 2nd Gen. Dodge Ram - No Drivetrain 11 11-22-2010 11:24 PM
SLT vs SLT Plus Pleyster 2nd Gen. Dodge Ram - No Drivetrain 21 03-21-2008 01:09 AM
Adrenaline questionI've .r3un zchornyak Performance and Accessories 2nd gen only 1 03-05-2008 06:39 PM
SLT vs. Non-SLT CZSteve 2nd Gen. Dodge Ram - No Drivetrain 13 04-21-2005 12:05 AM
1996 dodge dually 1 ton 2 wheel drive rodeo1 HELP! 6 11-23-2003 02:03 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 09:01 PM.


Copyright 2017, DieselTruckResource.com
We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.