Author Topic: 79/403 replacement driveshaft yoke  (Read 566 times)

TOG 6

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79/403 replacement driveshaft yoke
« on: July 07, 2022, 10:35:49 AM »
Swapped the THM350 fir a 200R4.
The driveshaft slip yoke has a ridge that's eating the rear tranny seal - I need to replace with a new one.

I see like 5 different yoke lengths for a 350/400 yoke -- any idea which is the right one?
Any idea how many splines?

No, I cannot currently just look under the car.

Thank you

81Blackbird

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Re: 79/403 replacement driveshaft yoke
« Reply #1 on: July 07, 2022, 10:51:21 AM »
Had that happen to me years ago.  Got a sleeve that was pressed over the yoke to solve the problem.

tajoe

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Re: 79/403 replacement driveshaft yoke
« Reply #2 on: July 07, 2022, 03:59:22 PM »
I have a few drive-shafts, and took some dimensions for you. Maybe it'll help. I agree with the poster above. Put a sleeve on it, and save a few bucks, unless you're Donald Trump. The diameter of the yoke on a TH400 is almost 2", (1.885...approx.), and the diameter of the yoke on a TH350, early Muncie, P/G, and probably a 200 is almost exactly 1 1/2". So if you can find a sleeve, make sure the ID isn't 2", but more like 1, 1/2".
"You can sell an old man a young mans car,
but you can't sell a young man an old mans car"
                                       Bunkie Knudsen
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TOG 6

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Re: 79/403 replacement driveshaft yoke
« Reply #3 on: July 08, 2022, 12:02:33 PM »
Thanks for the info on the yoke diameters - but what I really need is the total length.

tajoe

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Re: 79/403 replacement driveshaft yoke
« Reply #4 on: July 08, 2022, 12:46:09 PM »
Swapped the THM350 fir a 200R4.
The driveshaft slip yoke has a ridge that's eating the rear tranny seal - I need to replace with a new one.

I see like 5 different yoke lengths for a 350/400 yoke -- any idea which is the right one?Any idea how many splines?

No, I cannot currently just look under the car.

Thank you

What are you thinking? The yoke is too long, and on heavy bumps, it's bottoming out and smashing the seal axially? When you install the driveshaft, and the car is off the ground, (so can can see under it), load the rear suspension so the rear is at its normal ride height, and see how much engagement the yoke has on the seal. I'll take some yoke length measurements later, so you'll know what is there.
"You can sell an old man a young mans car,
but you can't sell a young man an old mans car"
                                       Bunkie Knudsen
<

Re: 79/403 replacement driveshaft yoke
« Reply #4 on: July 08, 2022, 12:46:09 PM »