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You are in the Dodge Dakota-2010 and older
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Dodge Dakota, Dodge, Suspension, Truck
#54 of 120 Differential ring gear size question. Need help!
Jan 27, 2008 (1:30 pm)
I removed the cover of my 1990 Dakota's rear differential (it's a 2-wheel drive) and counted 39 teeth on the ring gear and 11 on the pinion gear. Stamped on the ring gear is this: 2852943 - 3.55, also 10 25 89.
I'm guessing the 10 25 89 is the date of manufacture, October 25, 1989.
I've measured the gear ratio by turning the tire and the drive shaft and got 3.56, which is close-enough for me to 3.55, so I think the "- 3.55" means the gear ratio.
Maybe the 2852943 is the Chrysler part number. Can someone check this?
I took a string and used it to measure the circumference of the ring gear at its widest and got about 26 inches. If you divide 26 by 3.14 (pi), you get 8.28 inches for the gear diameter, which is closer to published numbers for Dodge's 8.25 inch gear than to Dodge's 7.25 inch gear.
But before this, I was told by a local used parts emporium desk jockey that the cover for the 8.25 inch differential is hexagonal while the 7.25 inch cover is rounded. My cover is rounded (actually elliptical), so he told me I had a 7.25 inch gear.
On the Internet I read that "Ring gear diameter can be identified by observing the housing tube diameter. The 7-1/4 inch axle has housing tubes which are 2.5 inch (63.5 mm) diameter at the inner ends and 3.00 inch (76.2 mm) at the outer ends; the 8-1/4 inch axle has housing tubes that are 3.0 inch (76.2 mm) in diameter."
My axle tubes are 3 inches O.D. for their whole length. Maybe this is another indication that I actually have a 8.25 inch differential.
Am I doing the ring gear measurement wrong? Should I be measuring around the widest part of the gear, or somewhere else? Am I wrong in thinking I have the 8.25 inch ring differential, or is the parts man wrong?
I'd sure be grateful for some help. I've never done any differential work, and this is the first time I've seen one opened-up.
#55 of 120 Re: Differential ring gear size question. Need help! [tjfitz]
Jan 27, 2008 (6:26 pm)
I believe the 8-1/4 inch has 12-bolt cover and the 7-1/4 inch has 10-bolts.
Most 2WD have the 7-1/4 while the 8-1/4 inch come thru installed on the 4WD Daks. Somtimes it seems that they installed whatever happened to be laying around the day the rear-axle was installed- LOL
#56 of 120 Re: Differential ring gear size question. Need help! [bpeebles]
Jan 27, 2008 (6:44 pm)
Thanks again, bpeebles.
My elliptic-shaped differential cover has 10 bolt holes in it. Also found when I took off the cover that there is a second metal tag under one of the two bolts that I left on while draining the oil. It has what looks like 3.5 stamped on it. The other tag has 3.189 stamped on it. The pinion gear driving the ring gear has several numbers painted in white on its end face inside the case. 4 and 1 are two that I remember.
#58 of 120 Ring gear is 8.25 inches according to local Dodge dealer
Jan 28, 2008 (9:07 am)
Well, I telephoned the local Dodge dealer and the parts representative said the number stamped on the gear, 2852943 - 3.55, was not a good one, but it probably indicates the ratio is 3.55. Using the last 8 numbers from the VIN, the rep was able to find that the ring gear is 8.25 inches. Now I can get on with ordering the carrier bearings and hope that I can get new ones installed and end the grinding.
Jan 31, 2008 (10:29 pm)
i was out 4 wheeling when i heard a clunk or a clicking sound so i put back in 2 wheeld drive . no noises but when back in 4 hi or low noise from right front axle any ideas thanks
#60 of 120 Special tool for carrier bearings adjustment?
Feb 17, 2008 (5:49 am)
I'm going to replace the differential carrier bearings in my 1990 Dodge Dakota rear wheel drive and have read that Dodge says to use their tool C-4164 (costs about $60) to spin the adjuster used to tighten and loosen the load on the bearings.
There is an interesting discussion about using a torsion bar from a 1970s era Chrysler/Dodge/Plymouth vehicle as a substitute for the special tool. Several posts in the discussion say the bar works perfectly, but the discussion ends with the man who asked the original question having his truck up on stands, the axles removed and a friend taking time off work to help only to find the torsion bar didn't fit!
I'm thinking of haunting the local junkyards to see if I can find one of those torsion bars to do my job, but am I heading for the same problem as the poster on that discussion? I'll be doing this job lying on my driveway outside in a North Dakota winter, and would probably have to lie in the snow in the junkyard to remove a torsion rod, so I don't want to waste a lot of effort, and would really be grateful for any input.
#61 of 120 Re: 2002 4x4 4.7 [roddinphxaz]
by KCRam@Edmunds HOST
Feb 17, 2008 (2:35 pm)
Check the Dodge Dakota 4x4 Issues discussion for better ideas, but it sounds like you may have popped an axle shaft joint.
kcram - Pickups Host
#62 of 120 Re: Noisy rear end after differential fliud change [dodgemon]
Mar 10, 2008 (3:41 pm)
I have a 2002 4x4 QC and it came with a 7 year 100,000 mile powertrain warranty, and they replaced both my front and rear diff. at the dealership...no charge. If yours is not in the same boat, beware. If you only replace the bearings, it will quiet down for a good month or so until those wear out too. So get the entire thing fixed right once at a reputable 4x4 shop.
#63 of 120 My torsion bar doesn't fit, either
Mar 12, 2008 (6:22 pm)
I finally got everything together, including the weather, to allow me to remove the differential carrier from the Dakota and on inspection found the carrier bearings and races are in very rough shape. I was relieved to find that, and am hoping the pinion gear bearings are OK. Also found the ring gear of the differential is indeed 8.25 inches diameter.
I'll bring the carrier to a local machine shop to have its bearings pulled and new bearings pressed-onto the carrier.
I got an old Chrysler motors torsion bar from a local junk yard for $2 and found it measures very close to 1-1/2 inches across the flats of the hex end. However the hex end is too big to fit the differential bearing adjusters (as found by the man at http://www.dodgedakotas.com/boards/gen/19427.html). The hole in the adjusters is very close to 1-29/64 inches across the flats. I still don't want to buy the Dodge part and am thinking of having the same machine shop skim some metal off the six flats of the torsion bar so it will fit the adjusters. It all depends on how much they would charge and whether they can machine that kind of metal.