T-Case Front Output Flange - Shot? 1976 FJ40 (1 Viewer)

[cdubatl]

Hi All - I think I know the answer but wanted to confirm, I had a leak on the front transfer case output. Tons of great info on the site so felt pretty good about it. I dropped the driveshaft, unstaked the nut, removed the seal, siliconed everything, torqued it all down, staked the new nut, high-fived the beer fridge.... Came out the next morning and small drips from the dust shield. Doh.

I thought I could get by with a pretty rough output flange. I guess not. Removed the stake nut, pulled everything and looked like it must have leaked between the new seal and the flange.

Questions:
1) Based on the photo does it look like that pitted flange is toast? I think so but am holding out that someone says nah just slap x on it, works all the time...
2) I used a speedi sleeve on the rear before which looks like a larger size ( I kept the install cap and compared it). Is there a smaller speedi sleeve available for the front?
3) If I need to get a new flange, when I search all the usual sites a lot of them look like round bases instead of the square. Are the round base flanges interchangeable?
4) Also, I'm assuming based on things I've seen here that this is considered a course spline with 10 splines. Is that correct?

Thanks everyone.

1st photo is the pretty new seal

2nd photo is the flange I'm assuming is done for - the black coming out of the splines is the RTV from yesterday.

 

[peesalot]

Yeah it’s not new , if you can find a good one for reasonable or you could try polishing that , some sanding tape, and for fine polish I use nail polish strips that I peel off wifeys long foam nail files , works great

 

[Living in the Past]

I would replace it. What you need to know is if you still have stock flanges. Besides the outer shape the bolt holes changed in size and pattern of the four bolts. Need to know year and for 74 model if it has a three or four speed.

What I wonder is the shape of the transfer case in general. The rusted pitted area is inside the seal where the oil is. If the seal is pitted how hard the bearings and gears?

 

[cdubatl]

Thanks. I tried cleaning it but agree in looking for a replacement. Once cleaned up you can see the extent of the pitting.

A newly polished pic. Think it still needs replacing? I imagine gear oil can get past that and a seal. Any recommendations on replacement - try to match existing square base or go round for appropriate year?

The replacement seal is OEM but looks different than the one it replaced. I think the previous lip either wore down over the years or design changed, regardless I would think the lip would help keep it tight. Is this a design change?

As for the transfer case - I wasn't concerned until now. It shifts ok but not smooth. I can get to all the ranges. I didn't think to take a pic while the seal was out. It didn't look perfect but nothing like dirt or baked. The oil was muddish in color when drained but now has all fresh - no obvious debris in the oil collector. It is a 1/'76 with 4speed. I think it is all original as it matches the diagrams in the FSM.

Next search may be on how to "power flush a transfer case without removing it or blowing every seal and gasket"

 

[pjohnson]

I'll just leave this right here...

Cruiser Outfitters

 

[numby]

Speedi-sleeve.

 

[Living in the Past]

Thanks. I tried cleaning it but agree in looking for a replacement. Once cleaned up you can see the extent of the pitting.

A newly polished pic. Think it still needs replacing? I imagine gear oil can get past that and a seal. Any recommendations on replacement - try to match existing square base or go round for appropriate year?
View attachment 2664377


The replacement seal is OEM but looks different than the one it replaced. I think the previous lip either wore down over the years or design changed, regardless I would think the lip would help keep it tight. Is this a design change?

View attachment 2664387

As for the transfer case - I wasn't concerned until now. It shifts ok but not smooth. I can get to all the ranges. I didn't think to take a pic while the seal was out. It didn't look perfect but nothing like dirt or baked. The oil was muddish in color when drained but now has all fresh - no obvious debris in the oil collector. It is a 1/'76 with 4speed. I think it is all original as it matches the diagrams in the FSM.

View attachment 2664412

Next search may be on how to "power flush a transfer case without removing it or blowing every seal and gasket"

If the oil was muddy when drained and pitting in the flange is inside the seal I would be concerned about the condition whats inside. More than just than flange got pitted. Muddy oil suggests it wasn't rebuilt after what ever happen to cause the pitting. Getting a leak fixed might be the least of the problems with the transfer case.

That extra lip is something newer than when these were built. Remember buying seals at least into the mid eighties without it.

 

[tone33]

This thread is helpful - I'm going through the same thing. My flange is also pitted. My truck is a '78 and looks like I have the fine-splined tcase. I've changed my gear oil several times since I acquired this truck and it stays clean, but then again I haven't put a ton of miles on it and haven't been through a whole lot of mud and dirt. You'll notice the seal in my pic is covered is grease and dirt/mud that's hardened. The dirt on the spline in the pic is from where i was scraping it off the outside part of the seal.

My tcase sometimes struggles to go back into 2H - I'm hoping it's not something internal, but I guess there's only one way to find out, unless anyone here has other ideas how to fix tcase shifting issues...

Also, bump for question on square vs round flange? I'm sure the good ole folks at @cruiseroutfit will know the answer..

 

[cruiseroutfit]

This thread is helpful - I'm going through the same thing. My flange is also pitted. My truck is a '78 and looks like I have the fine-splined tcase. I've changed my gear oil several times since I acquired this truck and it stays clean, but then again I haven't put a ton of miles on it and haven't been through a whole lot of mud and dirt. You'll notice the seal in my pic is covered is grease and dirt/mud that's hardened. The dirt on the spline in the pic is from where i was scraping it off the outside part of the seal.

My tcase sometimes struggles to go back into 2H - I'm hoping it's not something internal, but I guess there's only one way to find out, unless anyone here has other ideas how to fix tcase shifting issues...

Also, bump for question on square vs round flange? I'm sure the good ole folks at @cruiseroutfit will know the answer..
View attachment 3091893

View attachment 3091894​

Sorry, I’m not immediately spotting your question on the flange square vs. round profile. What’s your question?

 

[cdubatl]

The shape was the same thing I was uncertain on as well. I ordered the round one from cruiser outfitters and all worked great. Side by side below.

 

[65swb45]

This thread is helpful - I'm going through the same thing. My flange is also pitted. My truck is a '78 and looks like I have the fine-splined tcase. I've changed my gear oil several times since I acquired this truck and it stays clean, but then again I haven't put a ton of miles on it and haven't been through a whole lot of mud and dirt. You'll notice the seal in my pic is covered is grease and dirt/mud that's hardened. The dirt on the spline in the pic is from where i was scraping it off the outside part of the seal.

My tcase sometimes struggles to go back into 2H - I'm hoping it's not something internal, but I guess there's only one way to find out, unless anyone here has other ideas how to fix tcase shifting issues...

Also, bump for question on square vs round flange? I'm sure the good ole folks at @cruiseroutfit will know the answer..

Your post contains your best clue. If you’re having a hard time with the front drive shift collar, perhaps the bearing in the end of the main output shaft that supports the front output shaft and collar is failing. And if the bearing is failing, the front output shaft will not run or sit concentrically . And if the shaft is not sitting/running concentrically, then the seal will not properly seal ANY pinion flange.