I just bought a 3.07 Dana 36 from a forum member.

It looks very good. It has a date of 3/97 written on it. I assume it was rebuilt then. The gears turn easily and there are no chipped gears anywhere. The bearings all look good.

The seller told me it had 150,000 miles on it but that it was fine.

I didn't expect much. I planned to rebuild it. Should I just install it? How much should a total rebuild cost? I planned to bring it to a differential specialist. The pumpkin cost me $150.00 so I'm not worried about the cost of a rebuild. I'm just wondering if I should even bother.

Also, I was surprised to see a fill hole with a tag that says Posi Lube Only. I thought the Dana 36 was a sealed unit.

 

????? how exactly can you see the bearings if the cover is on and the gears have not been removed?
As far as being "sealed" you must be thinking about the fact that there is no drain plug, they all have a fill hole.

 

Yes, use posi lube as recommended...That is if you have a "good" posi installed in there. If you've had a look at the gears and they seem like they have a "normal" foot print throw the unit in and run it. You may want to check for excessive backlash with a dial indicator before you go through too much work. If used unit has a problem you only wasted some time and a couple quarts of oil.....you can reclaim the oil but not the time.

Good luck!

 

I mean the ones that are visable. The internal pats.

The ring and pinion look good and there appears to be some bearings on I think it's called the posi locker.

I not talking about the ones that are pressed on the ends.

As you may have guessed I don't know much about differentials.

Anyway you answered my question about the filler plug.

Maybe I should have new bearings pressed on and leave the rest alone.

I'm gonna stay with the 3.07s. I have 2.73s now.

 

Based on the mileage, if you aren't on a real tight budget new bearings and seals are a good idea. Great time to add a drain plug too, all you need is a 5/16" drill bit, a 1/8 X 27 pipe tap and plug to match.

 

OK, I'll check that out.

I just thought that the 2.73s with OD were overkill. That setup is good for cruising at high speed. My engine would lag at 60 mph in OD.

3.07s should be better around town and at the track.

 

None of the wear or working surfaces of ANY of the bearings are visible in an assembled diff. So there is no way you can say "The bearings all look good.". If the bearings were all pitted to hell, there is no way you would know without dissembling it and checking. If you decide to replace the bearings, that requires a new reset, or at least a verification, by a gear man. If you take it apart, you may as well replace the posi (not locker) clutches.

RACE ON!!!

 

Before you install it replace the clutches while you have it out of the car.

You like the 3:07 gears. There will be no lag at 60 mph.

 

Ok, I'm taking the diff to this place for a rebuild. They're about 3 miles from my house. They do rebuilds and installs. They also sell on the internet.

http://www.jawsgear.com/

 

The "first" thing I'd say you need to do is confirm the differential is what you believe you bought. You mention you know little about differentials and maybe the seller had similar experience! You need to count the number of teeth on the ring gear and divide by the number of teeth on the pinion gear! The results = axle ratio. The information is also generally stamped on the ring gear along with considerable gear information(depending on manufacturer)! It sounds like you actually purchased a carrier or "pumpkin" as it's referred to rather than a "differential". That description is usually reserved for an assembled unit complete with cover etc. If that's what you bought it might be wise to post a snapshot of it to see how complete it really is. If it doesn't have the short axles you'll need to transfer them from your old unit and they're needed to complete the build correctly! You could have the build done and then when you're ready to do the install have the shop swap the short axles and set the end play! You need to learn considerable before walking in the doors of "JAWS"!!!! You could be "devoured"!!!!!!!

 

The differential is the case the ring gear bolts to; the ring gear, diff (erential), internal, or posi case, loaded with the differential pinion and side gears.

RACE ON!!!

 

I bought the pumpkin from a forum member. He said it was a 3.07. He emailed me a copy of his build sheet.

The ring gear is stamped dana 41474. If you look at page 38 of the link below you will see that a 41474 is a 3.07 Dana 36.

I just got off the phone with Jeff from Jawsgear.com. He has been in business in Sacramento for many years and is highly respected. I have talked to him a few times at car shows. He usually has a stand at all the major car shows here. He said that my ring and pinion are in very good shape and he did not want to replace it.

He said that the bearings were OK with a little wear but that I should change them seeing that it is out.

I talked to him before about doing the 3.54 thick gear and he said I might get some gear whine. I took his advice and stayed with the 3.07. I think that is the best gear for my DD Vette.

He is now rebuilding the pumpkin and installing everything on Wed.

http://www2.dana.com/pdf/XGI.PDF

 

No that's really the case that the ring gear bolts to! The differential is the "assembly" or the "carrier complete w/housing". Actually most of the Corvette builders refer to the build of the rear as differential and is sold generally 2 ways!

1. complete w/short axles

2. less short axles

I was trying to head the OP in the correct direction.

Try these on for an explanation:

1. Spiral differential, pinion gear on center with ring gear. I'd say that's an assembled rear!

2. Hypoid differential, pinion below center on the ring gear allowing substantially more contact with the ring gear.

Differential I'd guess you would have to consider the assembly of the parts!

 

41474 ring gear is used with the 41467 pinion to make set number 72505-5X basic gear set usually sold as a 706870-5X. It has a 14 tooth pinion with a 43 tooth ring gear making a 3.07:1 gear ratio. Application: 36 ICA Dana axle.

RACE ON!!!

 

It sounds as if you've asked the right questions and confirmed at least what you bought! Your builder I would say advised you of what was needed! Staying with the build as it was(3.07) is a wise move. It's much easier to get a "good build" if all the internals are reused other than bearings. If it was quiet previously it should be also after the build! You'll know Wed evening it looks like!!

 

That is common usage, but as part of a quote from Abraham Lincoln says, "calling a tail a leg, doesn't make it a leg". The differential is the part of the rear (or front) axle assembly that allows for the differentiation in the speed of the two different axle shafts as the vehicle goes around a corner. The ring gear case IS the differential case as the contents, the side gears and pinions, make up the "differential"



Then you would be guessing. As for your examples 1. and 2. They are not an explanation, as you call them. They are just examples of common, but technically incorrect, word usage. Just because you or someone else has missapplied the word, "differential", doesn't change it's true meaning.

RACE ON!!!

 

Why can't you just deal with "functional descriptions"! Yes I understand a differential but relating in reality to the OP post and what the pinions and side gears accomplish but there's understanding and dealing realistically with the "rest of the world"!

-Functional description

The differential on the rear axle of a car

The following description of a differential applies to a "traditional" rear or front-wheel-drive car or truck: Power is supplied from the engine, via the gearbox, to a driveshaft (British term: propeller shaft), which runs to the drive axle. A pinion gear at the end of the propeller shaft is encased within the differential itself, and it engages with the large ring gear (British term: crownwheel), shown in the diagrams. The ring gear is attached to a carrier, which holds a set of three small planetary gears. The three planetary gears are set up in such a way that the two outer gears (the side gears) can rotate in opposite directions relative to each other. The pair of side gears drive the axle shafts to each of the wheels. The entire carrier rotates in the same direction as the ring gear, but within that motion, the side gears can counter-rotate relative to each other.

Thus, for example, if the car is making a turn to the right, the main ring gear may make 10 full revolutions, and during that time, the left wheel will travel more revolutions because it has further to travel, and the right wheel will travel fewer revolutions correspondingly, as it has less distance to travel. The side gears will turn in opposite directions relative to each other by, say, 2 full turns each (4 full turns with regard to each other), resulting in the left wheel making 12 revolutions, and the right wheel making 8 revolutions.

When the vehicle is traveling in a straight line, there will be no differential movement of the planetary system of gears other than the minute movements necessary to compensate for slight differences in wheel diameter, undulations in the road (which make for a longer or shorter wheel path), etc.-----------------------------

----------------------------

I didn't tamper with the text at all and I understand "every damned bit of it"! The first paragraph I'd say is a reasonable "functional description"! The balance was left in tact so that maybe you could try and absorb it!

 

Zip and Eckler's call em a differential. This is the part:

http://www.zip-products.com/Zip/prod...A4871364CB38B8


http://www.ecklers.com/product.asp?p...dept%5Fid=1858

 

When I look at what others are charging; I feel like a got a real bargain.

I didn't have to mess with shipping, handling and core returns. That could add a few hundred to the price.