rear end whine on '98 Ram 1500

I have a '98 Ram QC 1500, 92k miles, 2wd, Auto, 5.9 V-8 w/ 3.55 sure grip axle.

The differential has developed a high pitched whine that increases in pitch with speed, simultaneously the ABS and Brake lights have illuminted and the speedo does not register any speeds below 20 mph.

I am pretty certain the ABS/Speedo sending unit in the axle housing is bad....Any ideas what might have died in the differential any why? There is a fine metallic sludge in the bottom of the housing and some small metal chips/shavings/etc.

I plan to replace the ring and pinion with a set of Richmond 3.55's and ther complete overhaul bearing and shim kit.

I have the tool to adjust the carrier bearing preload on the way and have been able to get dial indicators torque wrenches and pinion depth tools from friends.

Anybody had there differential buy the farm? What was the cause? I was pulling an 1800# trailer when the whining started....Any suggestions or tips?

thanks- rich

Reply to
r_scotto
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It is a fairly common problem with this rear. They used lower cost pinion bearings in this rear and this happens more than most would like. The rest of the truck is built fairly well but another place to keep an eye on is the hard live going to the rear brakes up front where it crosses over the frame. It tends to rot out there.

Reply to
TBone

The biggest reason for this is neglect. Poeple tend to forget about rear axle and never change the fluid in them and this can cause premature failure. That rear axle is not that weak and if you had serviced it regulalry it would have likely never failed. Axle can have hard life but they can handle if properly serviced for usage. I would suggest that you go with at least 3.73 as the 3.55 will not save you any gas with OD. Also change axle lube about 1000 miles after installation (break in period) and about every 20 to 30K after that. Some use SYN fluid but it still get dirty and there is no filter back there. One final comment, I would call a Richmond Gear a "cheap" gearset and it would not be my first choice to use. I would suggest a Yukon or Precision Gear gearset.

----------------- The SnoMan

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Reply to
SnoMan

That is not what I heard. Someone told me he got 25 MPG with stop rear gears then switched to 3.73 for towing and it dropped to 21 MPG

Reply to
GeekBoy

Opps..typo.. STOCK, not STOP

Reply to
GeekBoy

Ok, I gotta break my silence on this one.

A halfton dodge of any sort getting 25 mpg? Is yours magical?

I rented a truck like yours, it got about 13. My 318/5 spd/3.21 gets about 12 mpg and its at a very tired 130k miles...

Hell, I know folks that would be trading in their out-of-tune chevy cavaliers for a 25 mpg dodge fullsize!

JS

Reply to
JS

Did not say it was Half ton

Reply to
GeekBoy

Then the relevance is kinda nil. A 1999 3.9L auto 3.55 2WD Dak extended cab will shit-n-get. A 1999 3.9 auto 3.55 2WD 1500 RC (this engine was not an option in the extended/quad cab) is completely gutless. They're fairly work-able with 4.10s tho.

Reason: Dakotas are much lighter and have a significantly smaller aerodynamic profile. It takes a lot less power to push them down the road. Also most of the driveline is lighter weight which greatly improves overall performance (that 6 ft long 2 piece cast iron drive shaft in my 318 half ton weighs a LOT, as do the 16x7 steel wheels and the big 265/75R15 all terrains... hmm.. no wonder it runs like a slug ;)

Also do realize your transmission actually gets beat on less with higher differential ratios. A reduced need to down shift and reduced cruising torque requirements can greatly extend transmission lifetime.

JS

Reply to
JS

Actually I was refering to 2500 CTD

Reply to
GeekBoy

Even so that is a bit of a reach imo

Roy

Reply to
Roy

Not when most people with 99 and up are reporting ~22 MPG

Reply to
GeekBoy

i get 21 IF i can keep my foot off the trottle......

19 most of the time with my normal driving to and from work/around town.
Reply to
Christopher Thompson

My current ratio is 3.55, I was considering 3.73 until I found that you can't find 3.73 anywhere. 3.21, 3.55, 3.90 and 4.10 are the only ratios I have found for the 9.25"

as an interesting bit of information regarding Yukon gear sets....this is what jawsgear.net says about Yukon gears:

"Yukon Gear Ring and Pinions are a mixture of several aftermarket brands of gears out on the market today. You could open the box and find a US Gear, Richmond Gear, Dana Gear, Motive Gear, Genuine Gear, or a true Yukon Gear. They are mixed to show a larger product line. If you are wanting a specific gear, be sure to call and verify what brand you might truely be getting This gear usually sets easily and runs quite when properly installed."

Reply to
r_scotto

And it doesn't even come close to using the same axle as the 1500 series.

Reply to
TBone

Automatic? 50 inch tires? 4x4? 4.11 rear end?

Reply to
GeekBoy

no 6 speed 3.73 rear end stock steel/michlin 17" wheels/tires

keep in mind my truck is an ST, no frills, bought it for what it was built for truck.

Reply to
Christopher Thompson

I agree with the magical part, I take this MPG claim with a grain of salt. No way a Dodge P/U with a 360 got 25 MPG. Typically they get about half that and sometime a bit better. The Dodge 360 gas motor does not have a good track record for fuel economy.

----------------- The SnoMan

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Reply to
SnoMan

Get your head out of the clouds and back to reality... that's a perfectly normal MPG rate for his truck. The 3rd gens, especially the '04.5's and up, get worse fuel mileage than a 2nd gen... the engines make more power, burn more fuel, the gear ratios are higher (3.54 used to be standard - now it's a

3.73), and the aerodynamics aren't as good as the 2nd gens.

I'm also in the 18-19MPG range (closer to 18) with "normal" driving. Like Chris, I can push it up into the low 20's with judicious use of the right pedal - but that's just not an fun.

Reply to
Tom Lawrence

The 5.9 sure can get that much with the 3.54 read end gears.

Reply to
GeekBoy

I have not messed with the 3rd gens too much. I know for sure my 2nd gen gets ~21 MPG highway miles with the rear end set at 3.73

At the price for fuel not I am considering going back to 3.54 to get 25MPG.

The thing is that my Banks Power Pack gives me just as much HP and torque as the 3rd gen without the fuel increase.

GB

Reply to
GeekBoy

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