redsscamaroboy

iTrader: (7)

98 Z28
4L80E swap
Which slip yoke do I need ?
99 truck transmission donor.

Used TH400 yoke but having issues with noise and vibration.
Over 50 mph has a harsh vibration from around Trans area.
Didn't have any vibration issues with the TH400 w/trans brake.
Used same driveshaft.
Any help is greatly appreciated.

redsscamaroboy

iTrader: (7)

A bunch of views , but no one has any info to share?
Come on gearheads, help a fellow car guy out.
Thanks in advance

wht/73

I would assume it was balanced when it was shortened?
Maybe a weight fell off?
Could be drive line angle too.

redsscamaroboy

iTrader: (7)

It was balanced when made for the TH400, D&R driveline made it.
The yoke can be rocked by hand at the tailhousing like its very loose fitting in the 4L80E . I got this car as a project car my friend built before his passing . I'm trying to get it sorted out to be race ready to see what it can do ,but this vibration is not gonna let that happen.
I think in need to verify the driveline angle is adding up , it's got a Moser 12 bolt and a short body mount Spohn Torque arm so there is adjustments available.

I see posts where people talking about a tailshaft housing bushing that's wears out and I need to know more about that to verify what's going on with it too.

Thanks for the ideas.

wht/73

Sorry about your friend.
Is it possible that the driveshaft isn't long enough and there's very little yoke engaged in the output shaft letting it pivot on it?
How far in does it go into the trans?

redsscamaroboy

iTrader: (7)

Thank you.
Car was in indoor storage for 4.5 years before I was offered the chance to pick it up and finish it.


I thought the yoke looked a little short , but , I haven't done a TH400 or 4L80E swap in an F-Body before so I have nothing to compare this with. <br/>

redsscamaroboy

iTrader: (7)

Current driveshaft has a Counterbored yoke , I noticed the output shaft has a threaded hole in the end.
So that makes the 99 truck a fixed yoke (donor),right?
Looks like this is the needed slip yoke.

http://www.dennysdriveshaft.com/p69_..._on_truck.html

Anyone care to comment on this being the needed yoke for my 98Z28 4L80E swap?

Thanks in advantage , David

wht/73

Mine was the same tailshaft. I used a 400 yoke that my trans guy gave me.

wht/73

That looks just like the one I used.

redsscamaroboy

iTrader: (7)

If I could post a video, I have a short video that shows how much the tail shaft moves without the driveshaft and how much everything moves with the driveshaft installed.
You can even hear the slop as it clunks and bangs with just slight pressure.
Trans has less than a few hundred miles on it , unfortunately I do not know who rebuilt it though. My friend only put around 25 miles on it before he passed and didn't tell anyone what he was doing to try to repair this.

Car went 11.01@127 on a Trans braked TH400, this setup was what he was working on and never got to finish and I am trying to sort out pieces and parts and previous work done to be able to complete the project.
Cars a Beast ,just vibrates like crazy about 50 mph and don't even think about doing a brake stand (sounds like it's gonna explode) low mph barely break traction kind of brake stand .
I read about one case where the poster found his tailshaft housing. Having had .025" wear and was out of round due to irregular wear from pinion angle issues and driveshaft whip (balance issue).
Still banging my head

redsscamaroboy

iTrader: (7)

Is that a shim under your Trans mount?

wht/73

Yes. That's The thickness of the ds loop that mounts to the top of the mount. The dam xmember sits to low and dizzy hits the firewall..so the shim/loop is needed.

redsscamaroboy

iTrader: (7)

Ok , got it. 👍🏽
Wondered if it was helping the pinion angle with the 80e swap.

wht/73

it could be hurting it! If so I need to get out the bfh and tweak the firewall!

SoFla01SSLookinstok

Would be cool to see the video. So is the tail shaft pretty solid with minimal movement? I actually had an experience with a slip yoke/vibe issue. Installed a new driveshaft/yoke. right away felt a vibration. Checked angles. Found it was actually the slip yoke itself. Must have been a cheaper unit that had too much clearance between the splines. Installed a new Mark Williams slip yoke. Fit like a glove/no more vibrations. Hope you get it figured.

redsscamaroboy

iTrader: (7)

Thanks for the input.

This ISN'T my trans, just a video I found that is very close to mine for movement

DailyGTO

That seems like a lot of play in that shaft. You said its the same driveshaft that didnt have vibrations before, but with the 4l80 there is a vibration, and there is a ton of play in the output shaft, so I would definitely be looking at the 4l80 being worn out. As to why the 4l80 is worn out, I dont know. Could be from improper driveline angle, or if the slip yoke is not playing nice with the output shaft etc.

FWIW, for my 4l80 swap I used the same yoke you listed from Dennys Driveshaft and it worked without issues at 128 mph on a stock foxbody driveshaft.

redsscamaroboy

iTrader: (7)

Thanks for the input, the 4L80e was only 25 miles old when I picked up the car so I can't see why it would be in bad shape. (Doesn't change anything if that's the case though,worn is worn.)
I am planning on picking up the Dennys Driveshaft yoke listed and checking the pinion angle . After that I am in over my head with what's next .

wht/73

I'd rather see the movement with the driveshaft installed. I would think there will be movement in any tailshaft without the yoke installed.

wht/73

I'll check and post mine before I put the DS back in.
Mine makes no noise.