Transfer Case Seal Replacement (1 Viewer)

[rstoddard]

I bolted the Retainer on, dry, with original gasket. No movement on the clutch input shaft gear at all. How should I proceed now? The old gasket looks okay, but I doubt it will make a good seal if it's supposed to seal out oil. Should I use a thread sealant on the retainer mount bolts?

Related question: I'm trying to make guide bolts to mount to top Bell Housing. I had a 1/2"-20 fine pitch on one side and what looks to be a metric bolt on the other side. I can't get the 1/2"-20 to fit into the hole that has (assumed) metric size fine pitch bolt. Do you know what the stock bolt hole is for that BH? I have a 6" 1/2"-20 I can stick in the hole, but I thought I would check before I tap it. The metric looking bolt seems a little loose in the hole, so I don't know what is up.

Ron

 

[h82crash]

Why did you remove the bearing retainer? In the interest of clarity, let's stop calling it a clutch gear. It is a transmission input shaft.

When you say the input shaft doesn't move at all, does it still turn smoothly? If so, seal it and yes, the bolts too if the holes are open to the inside.

If the bushing is still round and mostly smooth, it is probably fine. You cannot be sure, however, unless you remove the clutch and put a centering tool in and seeing if it has too much clearance. It should fit, a close slip fit and turn smoothly.



Not sure what bolt went into that bellhousing.

 

[rstoddard]

Why did you remove the bearing retainer?

I should have clarified that I was responding back to 65swb45. This has been a running thread so the explanation goes back to the fact that it was recommended that I replace the lip seal on the “input shaft.”

In the interest of clarity, let's stop calling it a clutch gear. It is a transmission input shaft.

I’ve only been using that description/term because that is how it is defined in the Muncie Transmission Manual pages I have, which use that nomenclature. Makes sense since it technically connects to the Clutch Hub, which is rotated by the flywheel when engaged. I have no issue if “transmission input shaft” is the more universally accepted name.

When you say the input shaft doesn't move at all, does it still turn smoothly? If so, seal it and yes, the bolts too if the holes are open to the inside.

If the bushing is still round and mostly smooth, it is probably fine. You cannot be sure, however, unless you remove the clutch and put a centering tool in and seeing if it has too much clearance. It should fit, a close slip fit and turn smoothly.



Not sure what bolt went into that bellhousing.

Thanks for your feedback and comments. I appreciate it. Mark (65swb45) asked me to bolt the retainer on to see if it was holding the bearing and shaft without any movement. I was looking for guidance from him on whether I should replace the gasket (or do anything else in terms of sealant/FIPG). I appreciate your advice to use the sealant on the bolt threads.

Ron

 

[h82crash]

I’ve only been using that description/term because that is how it is defined in the Muncie Transmission Manual pages I have, which use that nomenclature. Makes sense since it technically connects to the Clutch Hub, which is rotated by the flywheel when engaged. I have no issue if “transmission input shaft” is the more universally accepted name.

Ron

It wasn't a criticism. I was initially scratching my head when I first read "clutch gear. " I realized quickly and can see how some could call it such. And maybe the technical writers thought it was more descriptive that way. But, it's not a gear, it is a spline connection.

Anyway, looks like you're making progress.

 

[rstoddard]

It wasn't a criticism. I was initially scratching my head when I first read "clutch gear. " I realized quickly and can see how some could call it such. And maybe the technical writers thought it was more descriptive that way. But, it's not a gear, it is a spline connection.

Anyway, looks like you're making progress.

No problem. I didn’t consider it criticism.

The really hard part is going to be getting the tranny and TC back in.

 

[65swb45]

1. Since you have a new gasket, use it.
2. Apply a very thin coat of sealant. My current preference is a grey RTV sometimes referred to as FIPG. For that particular gasket a contact cement would be ok too.
3. As @h82crash pointed out, it’s important to seal the bolts too, and the fipg is good for that.
4. As far as the bellhousing bolts go, I m not sure how to advise.
Proceeding on the assumption that you’ve got a Toyota 3speed bellhousing, only two of the four holes are threaded, and they are metric. Since the GM transmission relies on the bellhousing having four threaded holes, they would have either had to put nuts inside the bellhousing, or tap it oversize, and ream the ears on the transmission accordingly.

 

[rstoddard]

It’s really weird. One hole on the BH is a perfect 1/2”-20 while the other is M12-1.25. Both are on the top. The bottom bolts both mounted from the inside of the BH into the Tranny and are 1/2” course thread. I assume the tranny bolt holes are OEM. My Tranny was designed for the Gama Goat so that may be why the bolt holes were added.

You mentioned previously about cleaning the tip of the Input Shaft with Emory Cloth. What grit? My retainer nose cone could use some cleaning too, but I didn’t want to put grooves with a course grit. Would a fine grit or steel wool be better?

 

[pb4ugo]

4. As far as the bellhousing bolts go, I m not sure how to advise.
Proceeding on the assumption that you’ve got a Toyota 3speed bellhousing, only two of the four holes are threaded, and they are metric. Since the GM transmission relies on the bellhousing having four threaded holes, they would have either had to put nuts inside the bellhousing, or tap it oversize, and ream the ears on the transmission accordingly.

The stk sm420 bolts installs the same way as you describe on w/the Toyota b/h. It's unique to the 420.

The upper trans mounting bolt holes are not threaded and the bolts thread into the bellhousing from the outside,⁸ and the trans lower mounting holes are threaded. The lower bolts go thru the bellhousing from the inside of the bellhousing and thread into the sm420 lower mounting holes, which are threaded.

This is why folks should get the gm 420 bellhousing and clutch fork with the 420 tranny when bolting it to a chev engine. The gm 420 b/h is open on the bottom w/a inspection cover.

 

[pb4ugo]

It’s really weird. One hole on the BH is a perfect 1/2”-20 while the other is M12-1.25. Both are on the top. The bottom bolts both mounted from the inside of the BH into the Tranny and are 1/2” course thread. I assume the tranny bolt holes are OEM. My Tranny was designed for the Gama Goat so that may be why the bolt holes were added.

You mentioned previously about cleaning the tip of the Input Shaft with Emory Cloth. What grit? My retainer nose cone could use some cleaning too, but I didn’t want to put grooves with a course grit. Would a fine grit or steel wool be better?

My guess is someone stripped the metric threads and retapped the hole to SAE, or they had to relocate the hole to match the 420 mounting flange and drilled and tapped. I am more familiar w/a sbc's, not sure what needs to be done to adapt a 420 to your application.

 

[rstoddard]

I don’t recall. I got the BH 20 years ago. I don’t recall tapping it, unless the threads were stripped when I got it.

 

[pb4ugo]

I don’t recall. I got the BH 20 years ago. I don’t recall tapping it, unless the threads were stripped when I got it.

Well at this point it doesn't really matter. I feel comfortable saying, Toyota didn't do it. Keep in mind when it was probably done, a 1/2-20 tap was easier and cheaper to to find than a metric tap.

 

[rstoddard]

1. Since you have a new gasket, use it.
2. Apply a very thin coat of sealant. My current preference is a grey RTV sometimes referred to as FIPG. For that particular gasket a contact cement would be ok too.
3. As @h82crash pointed out, it’s important to seal the bolts too, and the fipg is good for that.
4. As far as the bellhousing bolts go, I m not sure how to advise.
Proceeding on the assumption that you’ve got a Toyota 3speed bellhousing, only two of the four holes are threaded, and they are metric. Since the GM transmission relies on the bellhousing having four threaded holes, they would have either had to put nuts inside the bellhousing, or tap it oversize, and ream the ears on the transmission accordingly.

Mark, I got some gaskets from Advanced Adapters. I believe this one goes between the Adapter and the TC. Do you want me to ship it to you? I could probably send overnight or 2-day.

Ron.

 

[65swb45]

Should be finished later on this morning Ron.

 

[rstoddard]

Should be finished later on this morning Ron.
View attachment 2897672

Sounds & looks good. I waiting to hear about a minor surgery that is being scheduled. Not sure exactly when I can get out to pick up (either before or after). Is shipping possible?

I nearly have the transmission back in. The last 1/4-3/8 has been very tight. It didn’t slide completely in and snug. Couldn’t push that final gap. Assume it is having trouble getting into the bushing. All the bolts align. Is it wrong to drawn it in? It could just be a be a tight fit around the r
Bearing Retainer housing.

Ron

 

[rstoddard]

Sent USPS Overnight P1 guaranteed delivery by 6PM tomorrow (Wednesday).

 

[rstoddard]

Is P/U next Thursday 1/27 going to work? Between 12-2pm?

 

[rstoddard]

If you’re going to try that, I’d recommend pulling the top bolts out of the front motor mounts (to keep from breaking them) as well as keeping watch over your fan/ shroud clearances and valve cover to firewall.

Things can easily get pinched while you’re being focused on the underside.

Mark, I got the Transfer Case back in but I’m having trouble getting the motor mounts lined up. I didn’t have a problem getting the lower mounts aligned since they allow a little “wiggle” room to get things aligned. The problem is the right front (top) mount is off a hair and I can’t get it aligned to get the top bolt in. I loosened the bottom bolt of the mount, but it doesn’t allow any adjustments front to back ( just right to left). I’m off about 1/3 of the bolt size. It’s like the engine is just slightly twisted and it leave the engine side mount pushed slightly towards the back, and slightly out of alignment with the frame side. I don’t know how to “pull” it forward and lifting and pushing on the tranny or BH hasn’t seemed to help.

The only options I could think of were : (1) losses the other mounts, Start the engine and hope it shakes itself into alignment, or (2) loosen the other mounts and get a engine hoist and see if I can lift and pull the engine into the necessary alignment.

Thoughts?

Appreciate your help!

Ron

 

[65swb45]

You definitely need to start with the other mounts loose. Two floor jacks, one under the oil pan and one under the transfer case will help. With the battery tray out of the way, you can lever a 2x4 between the motor mount ear and the front axle housing for leverage.

There is occasionally a lot of jockeying involved, and none of it is high tech.

 

[rstoddard]

Great advice! Yes, the 2X4 on the axle helped push it into alignment with the help of a dozen or so blows from a hard steel pipe on the board to urge it on, and a little lift on the oil pan and TC. THANKS!!!