Stock transfer case on stock transnission ('78 40) is leaking behind parking brake drum. It sounds like, from what I hear, a common problem in these. I have not looked in the manuals yet and I am sure some on this board has had to replace this seal. Any tricks or suggestions?
XFER OUPUT SHAFT LEAK
- Thread starter 78mustard40
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Yup. Common problem. You'll need to replace transfer seal, and permatex where the seal implants into the brake housing. Where the rear output shaft rides on the seal there may be a groove. If you can catch your fingernail on the groove, it will contribute to the leak. SOR (or NAPA, if you know the part number) sells a Speedi-Sleeve which is basically a metal cuff that slides over the shaft to cover the groove. It is a good idea to put permatex on the teeth at the end of the output shaft when you reassemble it, too. Took all four steps for me to achieve a leak-free state.
Replacement of the seal is pretty straight forward. After draining the t-case, remove the driveline, parking brake drum, cable, shoes and backing plate. You will then be able to pull the seal and replace it.
The problem lies with the parking brake drum. The surface where the seal rides is usually grooved on older trucks, so replacing the seal is only a temporary fix. The groove will let oil past the new seal also. If this is the case for you, there are three common solutions to the problem.
1. Replace the parking brake drum with a new one. Or a newly welded and remachined one.
2. Speedi sleeve the grooved surface. Speedi sleeves are available from Chicago Rawhide or SOR
http://www.vsm.skf.com/usa/Automotive/index.html
http://www.sor.com/sor/cat068.tam?xax=16977&page.ctx=cat068.tam
3. Mudrak machines the output seal / speedometer retainer to accept dual seals. I've tried the speedi sleeve routine with limited success and will be going the Mudrak route next. My friends who've done the double seal swear by it.
http://www.mudrak.com/products.html
The problem lies with the parking brake drum. The surface where the seal rides is usually grooved on older trucks, so replacing the seal is only a temporary fix. The groove will let oil past the new seal also. If this is the case for you, there are three common solutions to the problem.
1. Replace the parking brake drum with a new one. Or a newly welded and remachined one.
2. Speedi sleeve the grooved surface. Speedi sleeves are available from Chicago Rawhide or SOR
http://www.vsm.skf.com/usa/Automotive/index.html
http://www.sor.com/sor/cat068.tam?xax=16977&page.ctx=cat068.tam
3. Mudrak machines the output seal / speedometer retainer to accept dual seals. I've tried the speedi sleeve routine with limited success and will be going the Mudrak route next. My friends who've done the double seal swear by it.
http://www.mudrak.com/products.html
- Thread starter
- #4
Thanks for the info guys. Just talked to Gary @ Mudrak's, nice guy, told me to send mine to him and for $50.00 he will do the machining and install the 2 new seals also. I owe you a 
for that info Shipwreck.
for that info Shipwreck.I tried the speedi sleeve approach to no avail. Waste of about$40, not to mention the time and frustration. Went to napa bought a single seal $3.50. The only thing I did different was use the old seal to drive the new seal all the way to bottom of housing putting the rubber part of the seal in a different position on the shaft. Also put some sealer at the end of the output shaft to keep oil from seeping around splines. My emer. brake works again and no embarrashing puddles of oil in other peoples driveways. If your seal was bottomed out might try leaving flush with out put shaft housing. But if you can get shaft maschined for $50 dollars that would be the best way to go.
If I remember correctly, you don't have to remove the brake shoes, etc. Just loosen the brake cable (at the firewall), and there was enough clearance to remove the whole assembly w/o dismantling it all. All I had to do was swap out seals (no speedi sleeve). Just make sure you compare your new seal with your old, test fit your seal on the brake hub (or whatever you want to call it). You could take the hub, seal, and some vernier calipers down to your Schucks, or wherever you go, and check out some different seals. Some of the guys who work at my local Schucks are total monkeys, but if you can get them to pull out the right part catalog, you can get seals, etc. based on mating surface dimensions. (The seal they gave me first didn't come into contact with the shaft, nor the t-case housing.
The napa oil seal is#17754 manufactured by CR or Chicago Rawhide demensions are 45X62X8---It does fit--- but still just a single seal. Did you know that leather was the first bearing, used on wagon wheels so as not to wear out the axles? Greased with animal tallow. Sorry I'm cooked I'll shut up.
