Redtruck-VA

Went to my local parts store to buy a bearing kit. There seems to be more than one for the 89 D250 3spd non inter cooled diesel. Can anyone tell me about this rear end?
I looked at the axle and thought there might be some markings on it. Found none that made sense to me. Turned the wheels and counted the drive turns and it is a 3:07. Any help is appreciated.

patdaly

You have a Dana 71 axle, it is essentially a Dana 70 except the center section is cut to accept a 3.07 gear.

They may have confused you with a 60 ( gasser ) and the 70/71 Diesel.

On Rock Auto they only list 1 set for the 70/71.

You may still have the tag, see this link for locating it.
http://quad4x4.com/dodge70rear1984-1993.html

Philip

Dana 71 3:07 gearing.

Redtruck-VA

I studied that site, excellent information. Much appreciate the inputs from everyone. Question, Does the Dana 71 come with both 35 and 32 spline axles?

NJTman

Take the cover off the diff.


On the edge of the RG (flat side facing you) you will see an alphanumeric number that usually starts with a T..... That Alphanumeric number on the RG will make it so you can order anything you want from your supplier.

Personally, I like these guys, and they sell the spicer parts the truck came with. Prices were good, and the guys knew everything about my rig from that number

http://www.drivetrainspecialists.com/about-us

Redtruck-VA

I was trying to identify it without having to pull the cover. Basically 4qts to look at the ring. Not a big deal I guess.

NJTman

On the passenger side tube, leading off the center section of the diff, there should be a number stamped into the tube. You probably have to grind off the years of crud, but it's supposed to be located there.

Philip

If the axle has studs with wedge locks its a 35 spline. If it has bolts holding the axle in its 32 spline.

I have heard of one 32 spline setup on another site.

71's are easy to spot without pulling the cover to count teeth or look for markings on the ring gear. Look at the pic you posted of the rear cover. At the 2:00 oclock and 5:00 oclock positions there are two pieces of casting that are wider than the diff cover. 3:54 + geared housings do not have those two over hanging pieces of casting.

Redtruck-VA

NJT/Philip,
Great information, this will help a lot, Got to see if my pressure washer will fire up....

Redtruck-VA

Pressure washed the housing and if there was anything ever stamped on it, it's gone now. I'll have to go to town to get some lub and pull the cover. Here is a picture of the hub and I'll call it a 35 spline axle.

Redtruck-VA

Ok, when I first got the truck a few weeks ago I checked the rear fluid level and found the rearend a qt low. Now with the cover pulled I think I have discovered the source of my rhythmic rumble. The oil was dirty but no detectable metal but there is some evidence of rust. I thought this truck sat for a long time and this supports that. Here are a bunch of pictures I took including the BOM on the ring gear. Maybe someone can elaborate on the findings.

Philip

I bet that rust isn't causing the rumble like you think. My money is on bearings.

Take a screw driver and see if you can move the carrier sideways.

How much back lash does the R&P have?

Pull the hold down caps off the carrier and see if the carrier bearings outer races have been spinning.

Remember wheel bearings can make that same sound also.

Redtruck-VA

The R&P back lash isn't all that bad I didn't measure it. But the there is axle play and there was a minimal amount of side play. I used a large screw driver and tried to move the carrier and it was so small I wasn't sure it wasn't my imagination. My reasoning for thing bearings was I could find the spot at cruise where I could hear it and let off the accelerator and the noise would stop. This isn't by any means loud. But now I have other thing quieting down I can hear little things better. So you think I should go ahead and change the bearings?

Thanks,

NJTman

RTVA,

I'm by no means a "differential expert", but I did sleep in a Holiday Inn Express last night....




So.

Your RG and Pinion are not meshing properly. If you look at the wear pattern you have there, the contact patch in facing the center of the gear. This means that the pinion is out of alignment with the RG, and it's not set to where the contact patch is placed evenly between the two. The rust shouldn't be still visible at the outer part of the RG as in your picture. The worn / smooth part of the teeth should be centered in each tooth. The worn / smooth part is only on one side, which means the Pinion is moved too far in one direction.

Proper contact between the pinion and RG are essential for the unit to last. It's possible that someone removed the yoke on the front of the diff to replace a seal, then over / under tightened it, changing the relationship between the two. You have too much "TOE" contact. You will need to increase the backlash (adding pinion shims) to get the ideal pattern to be centered. Personally I wouldn't do this unless I replaced all the bearings and spiders. Not worth resetting a used diff, IMO.



So, how do you fix it ? Read this:

http://www.pirate4x4.com/tech/billav...4b_Gear_Setup/

I've never done a complete rebuild, so I'm not the one to tell you exactly what to do, and how to do it. The link above helps by explaining what to do. Buy a rebuild kit, and reset the entire diff. Not sure if you can buy a new RG and pinion for a dana 71 or not, but that would be the way to go.

The numbers you want on your RG are the alpha numeric listing: P2R49

That's what the place will need to get you your parts.



hope this helps.

samiam4

Looks like the diff has had some moisture accumulation or been dipped dropping in a boat. There should be no side movement- it is suppose to be preloaded. You should measure and this is a pretty big job.
I got my bearing kit from Autozone's website for $155 + 10% gift card, free shipping and no sales tax. It was a timken kit.
Cleaning out the tubes of rust/debris/old oil is not fun. They ussually spin/spit the shims on the thrust side of the Ring gear. That's driver's side.
Mine was limited slip and i had to get new side gears too $$. You could get the clutch kit cheap on Rockauto the last time I checked.
Lots of work pulling, dye, check pattern, repeat. If space is available- I would pull the axle and do it on the shop floor. In the truck sucks.

Just a heavy carrier assy.
Michael