Transfer case seals leakage.
Posted: Fri Jul 10, 2015 3:54 pm
The GMC CCKW
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Transfer case seals leakage.
Page 1 of 1
Re: Transfer case seals leakage.
Posted: Sun Jul 12, 2015 1:12 am
Hi Fernando,
Looks like you are getting some practice making gaskets
. I just did the same job on my truck last winter. Are you going to replace the shift shaft seals, too?
How do your driveshaft flanges look? Mine were in pretty bad shape. Lots of pitting on the sealing surface. I'm thinking that those old leather seals must either hold water, or possibly the have residual tannic acid in them - which attacks the metal in the flange. ( I think that modern nitrile seals are far superior to the old leather ones. )
I was going to install sleeves, but I thought I would see if I could clean them up first. If you have access to a lathe, it is pretty easy. I'm no machinist, but I was able to get them all looking smooth and shiny again.
Basically, what I did was find a piece of scrap aluminum to use as fixture. I drilled four holes in it to attach the flange (these pics are from the differential flanges, but it is the same procedure). I then put the flange in the chuck, spun it on the lathe, and trued up the OD of the fixture. I then stopped the lathe, turned around the piece and stuck the fixture in the chuck, then turned the lathe on again, then cleaned up the flange.
Once you have the fixture, you can use it for any of the flanges, since the bolt pattern is the same. It helps to make the bolt holes slightly oversize, so that you can true up any flange first by gently tightening the bolts, checking and adjusting run-out using a dial indicator, then tightening them down.
Depending on how bad the flange is, it only takes a couple of passes to clean it up. Maybe 0.005" to 0.007", which is well within the range of the new, modern seals.
Its also a good idea to put a little sealer on the ends of the splines, near the retaining nut and washer, to keep and oil from seeping out through the splines. I used this stuff made by Permatex. It is a silicone sealer specifically formulated for use with gear oils.
http://www.permatex.com/products-2/prod ... ker-detail
So far mine are not leaking yet
Best Regards,
Looks like you are getting some practice making gaskets
. I just did the same job on my truck last winter. Are you going to replace the shift shaft seals, too?How do your driveshaft flanges look? Mine were in pretty bad shape. Lots of pitting on the sealing surface. I'm thinking that those old leather seals must either hold water, or possibly the have residual tannic acid in them - which attacks the metal in the flange. ( I think that modern nitrile seals are far superior to the old leather ones. )
I was going to install sleeves, but I thought I would see if I could clean them up first. If you have access to a lathe, it is pretty easy. I'm no machinist, but I was able to get them all looking smooth and shiny again.
Basically, what I did was find a piece of scrap aluminum to use as fixture. I drilled four holes in it to attach the flange (these pics are from the differential flanges, but it is the same procedure). I then put the flange in the chuck, spun it on the lathe, and trued up the OD of the fixture. I then stopped the lathe, turned around the piece and stuck the fixture in the chuck, then turned the lathe on again, then cleaned up the flange.
Once you have the fixture, you can use it for any of the flanges, since the bolt pattern is the same. It helps to make the bolt holes slightly oversize, so that you can true up any flange first by gently tightening the bolts, checking and adjusting run-out using a dial indicator, then tightening them down.
Depending on how bad the flange is, it only takes a couple of passes to clean it up. Maybe 0.005" to 0.007", which is well within the range of the new, modern seals.
Its also a good idea to put a little sealer on the ends of the splines, near the retaining nut and washer, to keep and oil from seeping out through the splines. I used this stuff made by Permatex. It is a silicone sealer specifically formulated for use with gear oils.
http://www.permatex.com/products-2/prod ... ker-detail
So far mine are not leaking yet
Best Regards,
Re: Transfer case seals leakage.
Posted: Sun Jul 12, 2015 6:11 pm
Put a little dab of Permatex Aviation Form a gasket on the bolt threads or they may weep.
Also, it this is a Banjo xfer, use M211/M135 NOS seals. They are a lot better. You may have to push the U-joint flange into the seal them mount the flange. They are tight, but do not leak.
Also, it this is a Banjo xfer, use M211/M135 NOS seals. They are a lot better. You may have to push the U-joint flange into the seal them mount the flange. They are tight, but do not leak.
Re: Transfer case seals leakage.
Posted: Mon Jul 13, 2015 6:14 pm
Hi Mudflap.For a while I am only making gaskets.Who did all my service is my mechanic Joseph.We only changed two transfer case seals front and rear.I will not change the shift shaft seals.My driveshaft flanges were not so bad. Excellent job you did.No more leak.Regards.Fernando.