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Old 02-19-2017, 06:31 AM   #10 (permalink)
slowmover
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Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
Thanks: 1,422
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Scale it, Hersbird. As in my post to you on skykings thread. Data collection. And best tire pressure FF/RR.

Mechanical condition is uppermost for these trucks. Confirm that post-2008 steering conversion has been done and that balljoints (every 70k) have been recently replaced. All book maintenance thru 300k. Recent valve adjust? New boots on CAC system? No caliper drag? Perfect alignment? (See rdefayette posts on same at CF). Mech malfunctions hide underneath disciplined driving. Skew results.

As in another thread: how many years will you have this truck? How many miles annually? (Come up with something). Ownership CPM per worksheets at Edmunds or AAA (True cost of ownership).

Given X-miles annually, at an estimated Average mpg, what is annual consumption? What percentage change to the annual average would produce a $1000 savings? (Work these type questions).

Second, as skyking and others have noted, about the only effective changes are aero for highway and final gearing. If the vehicle sits around waiting to pull a travel trailer, changing to 3.42 will work against you. If the vehicle is mainly a commuter (where pulling a TT is 30% of total annual miles) a final gear change may be effective. And then it depends on TT aero and weight. Plus terrain and climate.

A-B testing. Keep it simple. Same pump before/after same 1-200 mile highway loop. On cruise control at 60-mph or lower. Truck empty, truck with more than 1k payload, and truck with trailer both loaded for camping trip. (Simulate passenger weight). The percentage change between these different states is what matters. Not the numerical mpg. Use engine rpm to set cruise at same spot on highway entrance ramp.

Cruise control is "assertive" on these trucks. Assumes truck is under a load. Let it do its thing in any state. It's reliably regular, overall.

Steering and tire choice if bad is 4-mpg easily. To the annual average. A greater effect than tank by tank (which is pretty much meaningless). Without "like new" mechanical condition per steering, front end and tires, "testing" is a time and dollar waster.

Were it mine I'd be looking at replacing all fluids filters belts and related. U-joints. Front axle bearings. (and further as in that post).

Rent a steam cleaner to get underside and repaint where corrosion has started.
New exterior lamps, etc. A copy of the state inspection form to thoroughly go over details.

There are some potential suspension improvements for handling/steering, but they also limit wheel travel some feel necessary for 4WD. How will you use yours in that regard?

Pics of your camper, or similar to what you want to do would be a help. Neckover goose type. 5er hitch? Conventional? Probable weight? Etc.

Congratulations on a fine looking truck!!

Last edited by slowmover; 02-19-2017 at 06:43 AM..
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