Help! drive shaft doesn't bolt to 489 carrier case.

[Agentstu]

Help! I just switched from a 742 case to a 489 case in a 8 3/4 attached to a 1969 roadrunner. The problem is the drive shaft appears to be short or the 489 case is smaller than the 742 case. Now the drive shaft doesn't reach the 489 case. How do i fix this?

 

[67 coronet]

the two third members should be almost the same length.are you positive you didnt do anything else?did you just swap out 3rd members or did you switch axle assemblys?

 

[Cranky]

Shouldn't be any difference in the length. How much longer does the drive shaft need to be?

 

[Bad Sport]

When you pull the shaft back to meet the carrier how much of the front slip yoke is exposed? The slip yoke should not be bottomed out in the trans.

 

[Agentstu]

The 742 case was an open and the 489 was a sure grip. The only thing i did was remove the 742 center section and install the 489 center section. For some reason i have about an inch or so seperation from the drive shaft and 489 case. Didnt have this problem with the 742 case.

 

[Bad Sport]

See post #4

 

[Agentstu]

The slip yoke doesn't touch the flange on the 489 center section. I tried pulling the drive shaft closer but it doesn't move. I also read online that the b bodies came with two different drive shafts depending on what size engine.

 

[Cranky]

Just pull the shaft back to the rear yoke and bolt it up then check to see how much of the front slip yoke is showing.

 

[Agentstu]

Can the drive shaft move back and forth? If that's the case maybe i didn't pull hard enough. I bench press 275, so i think i pulled hard enough, but i will try again.

 

[Agentstu]

I have to work today so i will check back in tomorrow for updates and the conclusions.

 

[Bad Sport]

Yes it moves, hence the term "slip yoke". The yoke in the trans slides in and out. Once bolted up you do not want the yoke bottomed in the trans as it can break the tailshaft. Conversely you don't want too much of it out of the trans either.

 

[Garys1969RR]

I have changed several 3rd members in 69 RR and 70 Super Bee. Only thing I had to sometimes change was the companion flange on the carrier. There are 2 different widths. Also your drive shaft has to be pushed into the transmission a little to even get the rear u joint out of the 3 rd member. Did you push the drive shaft into the trans a little to disconnect it?

 

[daredevil]

Doesnt make sense. Front driveshaft yoke slides on trans output shaft. Maybe you pried the rear and shaft apart and its stuck on the trans shaft.Theoretically the problem you have is impossible.

 

[benno440]

pull shaft out of gearbox reinsert to gearbox slowly and gently then bolt it to your carrier

 

[RustyRatRod]

Just pull the drive shaft back and bolt it in.

 

[Agentstu]

Wow I can't believe it was that easy. I pulled on the drive shaft with a little muscle power and bam problem solved. It bolted right in with no problems. This website is the best thing since mashed potatoes and gravy. Thanks for all the help.

 

[Garys1969RR]

Sure, Agentsu. I also have a 1969 Road Runner I just went thru the entire car mechanically. Even re built a motor for it. So anything you need to know, we can help you. Good luck!

 

[RustyRatRod]

This website is the best thing since mashed potatoes and gravy.

No it's not. Not the way my wife fixes um. YUM.

 

[Photon440]

No it's not. Not the way my wife fixes um. YUM.

I'll be there for dinner.