4R70W Tailshaft Leak

Joined: May 20th, 2004, 11:45 pm

September 7th, 2005, 1:38 pm #11

The rear 'seal' is a dust seal -- not a pressure seal so you are probably just overfull. Drain it down a bit and then check back in.

It's easiest to pull the tailshaft off (jack the tranny, remove x-member, driveshaft, unbolt tailshaft...) and replace the seal off the car.
I've been on the road most of this month so I haven't tackled this yet. Before I go and buy parts, is the "rear seal" more than just the rubber boot on the back of the transmission? If it's just that rubber boot, that couldn't really be the source of my leak, could it?

'69 Mustang Convertible
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Joined: May 20th, 2004, 11:45 pm

September 7th, 2005, 1:40 pm #12

I recently swapped a 4R70W into my '69 Mustang. The transmission works great with the Baumann controls, but I have a fairly bad leak from the rear. Is this most likely just the output seal/bushing? What else might cause that? Also, what all is involved in replacing both - do I just pull the housing off and do it, or can it be done with the housing in place?

Thanks!

EDIT: Probably wishful thinking, but is there anyway an overfull case can lead to a output seal leak? I think I may have overfilled the transmission quite a bit initially since I had a broken dipstick -

'69 Mustang Convertible
I've been on the road most of this month so I haven't tackled this yet. Before I go and buy parts, is the "rear seal" more than just the rubber boot on the back of the transmission? If it's just that rubber boot, that couldn't really be the source of my leak, could it?

'69 Mustang Convertible


'69 Mustang Convertible
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Joined: November 18th, 2004, 4:20 am

September 7th, 2005, 3:11 pm #13

The rubber boot is a dust seal. It is part of the actual seal.
The oil seal portion is in farther.
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Joined: May 20th, 2004, 11:45 pm

September 7th, 2005, 10:20 pm #14

Thanks Stuart - got the part this afternoon - looks just like a rear end housing seal inside. I'm pretty sure I'll find that I damaged the old one when I stuck the smaller yoke in there and wiggled it around -

'69 Mustang Convertible
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Joined: May 20th, 2004, 11:45 pm

September 7th, 2005, 11:24 pm #15

I've been on the road most of this month so I haven't tackled this yet. Before I go and buy parts, is the "rear seal" more than just the rubber boot on the back of the transmission? If it's just that rubber boot, that couldn't really be the source of my leak, could it?

'69 Mustang Convertible


'69 Mustang Convertible
Okay, I finally got under there again today. I haven't removed the tailshaft housing, but there is a ton of play in the output shaft. I can wiggle it a good 1/8" or so either way. Is that most likely a bad bushing, or could something else be wrong? What would cause the bushing to go bad like that? I didn't have any driveline vibration, so I don't think it's out of balance.

'69 Mustang Convertible
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Joined: November 18th, 2004, 4:20 am

September 8th, 2005, 12:27 am #16

Is the wiggle with the drive shaft removed?
if so, no problem.
If there is lots of movement with the shaft in either the bushing, yoke or both are worn.
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Joined: May 20th, 2004, 11:45 pm

September 8th, 2005, 2:01 am #17

It only wiggles with the driveshaft out - when it's in, it's a solid fit. You'll definitely make my day if you tell me the shaft should have some play without the yoke in there!

'69 Mustang Convertible
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Joined: May 20th, 2004, 11:45 pm

September 8th, 2005, 8:03 pm #18

I recently swapped a 4R70W into my '69 Mustang. The transmission works great with the Baumann controls, but I have a fairly bad leak from the rear. Is this most likely just the output seal/bushing? What else might cause that? Also, what all is involved in replacing both - do I just pull the housing off and do it, or can it be done with the housing in place?

Thanks!

EDIT: Probably wishful thinking, but is there anyway an overfull case can lead to a output seal leak? I think I may have overfilled the transmission quite a bit initially since I had a broken dipstick -

'69 Mustang Convertible
 
Last edited by 69convert on September 9th, 2005, 10:23 pm, edited 1 time in total.
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