Rear Differential Questions (Diff Cover Off)
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
Rear Differential Questions (Diff Cover Off)
Changing the rear differential fluid for my first project on my 2001 F-350 7.3 DRW.
Noticed what looks like rust on the inside of the diff cover and on the magnet. Should I simply clean it and move on? See attached picture.
Some other thoughts in case it helps.
(1) I believe I have a Dana 80 as the cover reads as follows: DANA [next line] 47717 1[next line]208 0[next line]Rev D[next line]05 14 99. See attached picture.
(2)The small tag reads as follows: 41-10 [next line] 4 10. See attached picture.
(3) The large tag reads as follows: 4?10 (upside down triangle) 1C34 JA [next line} (upside down triangle) 606609-6 LS. See attached picture.
(4) I've also attached a picture of the large and small gear inside the differential. If someone knows what the numbers on the gears mean, I would love to know. (In case it's not clear in the picture, the large gear reads as follows: 09 11 00 Dana D 50551 J2L93 41 10 702 )
Thank you all for your help!!
Noticed what looks like rust on the inside of the diff cover and on the magnet. Should I simply clean it and move on? See attached picture.
Some other thoughts in case it helps.
(1) I believe I have a Dana 80 as the cover reads as follows: DANA [next line] 47717 1[next line]208 0[next line]Rev D[next line]05 14 99. See attached picture.
(2)The small tag reads as follows: 41-10 [next line] 4 10. See attached picture.
(3) The large tag reads as follows: 4?10 (upside down triangle) 1C34 JA [next line} (upside down triangle) 606609-6 LS. See attached picture.
(4) I've also attached a picture of the large and small gear inside the differential. If someone knows what the numbers on the gears mean, I would love to know. (In case it's not clear in the picture, the large gear reads as follows: 09 11 00 Dana D 50551 J2L93 41 10 702 )
Thank you all for your help!!
Lead Driver
Joined: Mar 2000
Posts: 9,359
Likes: 1
From: Hampstead, NC
Hello and welcome to FTE.
While it is possible that is rust, I doubt it. Looks like gear oil (old) to me.
Not sure about the numbers, but yes it should be a Dana 80 in a dually.
The small tag identifies gear ratio, in this case 4.10's
That ? between the 4 and 10 is an L, as in limited slip differential.
Don't know about all the other numbers (I suspect part numbers) but again the 41/10 are tooth counts on the ring (large) gear and pinion (small) gears.
While it is possible that is rust, I doubt it. Looks like gear oil (old) to me.
Not sure about the numbers, but yes it should be a Dana 80 in a dually.
The small tag identifies gear ratio, in this case 4.10's
That ? between the 4 and 10 is an L, as in limited slip differential.
Don't know about all the other numbers (I suspect part numbers) but again the 41/10 are tooth counts on the ring (large) gear and pinion (small) gears.
Thread Starter
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
It was definitely rust. I took a wire wheel to it and there was pitting underneath. I'm not sure I'll be able to save the plug but I'll try.
I'll take a look but I think the rust was below the oil line so I'm not sure how it would have formed.
Thankfully, the gears looked well oiled and had no play.
I sanded and repainted the cover. I hopefully will be able to reinstall tomorrow.
With the rear mounted 40 gallon tank, I'm going to have trouble getting the gear oil in without a pump.
Thank you.
I'll take a look but I think the rust was below the oil line so I'm not sure how it would have formed.
Thankfully, the gears looked well oiled and had no play.
I sanded and repainted the cover. I hopefully will be able to reinstall tomorrow.
With the rear mounted 40 gallon tank, I'm going to have trouble getting the gear oil in without a pump.
Thank you.
Thread Starter
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
Last question (I hope).
The bolts came off relatively easily.
I noticed they (the bolts) had some grey (dried) stuff on them.
Is that dried grey stuff the silicon gasket material i can't tell what color the gasket material under the cover was), some type of thread sealant, or ???
Thank you.
The bolts came off relatively easily.
I noticed they (the bolts) had some grey (dried) stuff on them.
Is that dried grey stuff the silicon gasket material i can't tell what color the gasket material under the cover was), some type of thread sealant, or ???
Thank you.
Fleet Mechanic
Joined: Jul 2011
Posts: 1,667
Likes: 5
if theres no rust or pitting where the ring and pinnion mesh, you should be fine. the cover bolts commonly get silacone or sealant on them during assembly.
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FTE Leadership Emeritus
Joined: May 2001
Posts: 13,653
Likes: 6
From: Cabot, Arkansas
Last question (I hope).
The bolts came off relatively easily.
I noticed they (the bolts) had some grey (dried) stuff on them.
Is that dried grey stuff the silicon gasket material i can't tell what color the gasket material under the cover was), some type of thread sealant, or ???
Thank you.
The bolts came off relatively easily.
I noticed they (the bolts) had some grey (dried) stuff on them.
Is that dried grey stuff the silicon gasket material i can't tell what color the gasket material under the cover was), some type of thread sealant, or ???
Thank you.
That is grey silicone sealant. If there was a gasket under there somebody added it after the fact. That grey sealant was the only thing sealing it from the factory.
Refill the diff with synthetic 75W-140. Skip the friction modifier.
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
Thanks. Purchased Mobil 1 synthetic gear oil (75-140) for the rear and (75-90) for the front.
Just not sure how I'm going to refill it with that tank in the way.
Really don't want to purchase a pump if I can avoid it.
Other posts have suggested adding the friction modifier (1 oz at a time) if I hear a clunking sound. Not sure why I would hear clunking from the rear wheels since I don't think they turn. ???
Just not sure how I'm going to refill it with that tank in the way.
Really don't want to purchase a pump if I can avoid it.
Other posts have suggested adding the friction modifier (1 oz at a time) if I hear a clunking sound. Not sure why I would hear clunking from the rear wheels since I don't think they turn. ???
9 ECHO 1
Joined: Aug 2009
Posts: 12,467
Likes: 58
From: Missouri
The clunking noise you will hear will happen when you turn if there is not enough LS additive. This is because the clutchs will have too much grip and your outside tire will literally be dragged as it will be traveling the same distance as the inside wheel, but as we know, the outside wheel actually has further to go and needs to spin faster, but with no LS additive it will essentially be locked to the inside wheel.
But again, dont worry about it. If you notice some clunking, go to a dealer and get some LS additive, but you shouldnt have any problems.
Thread Starter
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
I am on level ground, am filling up a Dana 80 on a DRW truck and have filled 5 quarts and am still not at the fill line. I don't have any visible leaks.
Help - is this normal?
Help - is this normal?
Thread Starter
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Laughing Gas
Joined: Jul 2012
Posts: 856
Likes: 63
From: Los Angeles/Ventura, CA
Mike,
I agree - 8.5 pints is what the manual says.
I still seem to be about 1.5" below the bottom of the fill plug. I guessing I should just keep adding fluid until it leaks out.
My bigger problem right now is with the fill plug on the transfer case. In my other post, I note that the plug no longer goes in the whole way - it only goes in about 60% with an Allen wrench.
David
I agree - 8.5 pints is what the manual says.
I still seem to be about 1.5" below the bottom of the fill plug. I guessing I should just keep adding fluid until it leaks out.
My bigger problem right now is with the fill plug on the transfer case. In my other post, I note that the plug no longer goes in the whole way - it only goes in about 60% with an Allen wrench.
David
