Thread: Mild vibration at speed

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Is this a new build, or something that's been in use for a while when the problem started? Automatic trans?

I'm thinking maybe torque shudder. What you describe would likely be a problem in the trans, not the TC it's self. It seemed to be fairly common on ford trucks, alot of times a fluid and filter change would take care of it if caught early enough. I'm far from an expert, just adding a new idea to the mix.

Its a new build. TH350 trans, 9" Ford open rear, 3.00 gear. Transmission is rebuilt, so the fluid/filter in it should have less than 100 miles on them.

Originally Posted by joeybsyc

and see if i can find a place that can balance it, i heard the driveshaft shop in town doesn't do that (go figure) but that a semi-local machine shop does. In an unrelated "event", I snapped off my throttle cable right in front of my buddy's house... He egged me on into gagging on the throttle a little, and when i did, the Lokar cable pulled right out of the clip at the carb end. The return springs did their job, but I've decided that cabe is a pretty lousy design... did a band aid fix to get it home, but will be re-engineering that too I think.

Be sure and take the rear U-joint with you to the machine shop when you have the driveshaft balanced.
And the front yoke remains attached.
They need em so they can set the shaft up in the machine.

(I'd give Deuce's 180 degree driveshaft flop a shot before doing anything else.)

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Here's what you need for throttle linkage.

Just call it a one strand, non-deflected throttle cable.

Originally Posted by DennyW

That one strand non-deflected throttle cable, looks like the same one I made up for my Nephew on his project. A nice piece of hot roll, and little heat, bend a 90º, and thread the end, and Wa-La. A Cable is born. I polished it, and clear coated it.

I'm glad to see that I'm not the last rod builder who prefers throttle rods instead of cable.

Granted, throttle cables can make life easy and in some cases are a necessity, but I see way more problems with them than with throttle rods.

Aside from a little work - threading, cutting to size, buffing etc. - making a throttle rod is no big deal.
I use 1/4" stainless rod and quality Heims from a bearing house.

Heims are about $5.00 - $7.00 each nowadays.
Including the stainless rod there's about $12.00 in the one shown above and nowadays it can still be done for less than $15.

Fwiw, the little firewall gizmo shown where the throttle rod goes through the firewall is a fume/heat sealing device that has a Teflon floater that moves as the throttle rod rises and falls as it operates.
Takes into account transverse torque movements as well.
Shown in the two pics of my 31 below.

Originally Posted by DennyW

That looks very nice for sure. On my Nephews, his throttle bar linkage extends to the outer firewall, so his was really easy. I just bent the rod on one end, drilled the hole in the rod, to allow for a washer on each side, and a small spring clip to finish it off. The other end, I used an old time ball and socket for the adjuster, and simply threaded the rod. I tried to keep it old looking to match his 64 Chevy truck. I'll have to get a couple pictures to show.

Where did you pick up the gizmo at ?

Thanks.
My own idea and you're looking at a couple of different ways to do it.


The 32 has a step machined into the aluminum escutcheon.
The smaller in diameter Teflon floater sits inside the step which is slightly deeper than than the floater is thick.
It also rides on a 'full-size' Teflon backing plate.
It's worked well for a lot of miles - perhaps 35,000 or so.
The hole drilled in the floater is 1/4" as is the throttle rod.
Ater a few hundred miles the fit became a bit loser and wear after that was virtually non-existent.


The 31's gizmo is a litte different.
I was going to do a tech article on making them and wanted to show another way to do it for rodders who didn't own a lathe.

Basics are, there's a Teflon backing plate, a Teflon floater and a Teflon ring between aluminum escutcheon and Teflon backing plate.

The aluminum escutcheon is a simple flat piece cut out with a hole saw and finished with file and 3M abrasive pad in a drill press using a mandrel.

The 31's Mark 2 version looks like it will operate just as well as the 32's prototype that's machined etc.

The pic should give you an idea how it's constructed.

I guess that's enough of highjacking Joey's thread . . . today....

Well, i took the U joint out at the rear, rotated it 180 and reinstalled it... It didn;t cure anything completely, but i swear it feels a little better... might just be me getting used to it though. I didn't do anything with the front U joint. The rear felt nice, and was new looking, no sticky spots or anything. I also adjusted the master cylinder rod and made the rod a bit longer so i didnt have to push the pedal as far down to get brake... seemed awesome when i left this morning, but about 30 miles down the road my front brakes (maybe rears too) were dragging severly and were almost locked up. Why would this happen after driving that long without a problem? My guess is that the piston actually had slight brake pressure applied at all times, and after 30 miles the heat built up enough that the brakes actually wanted to lock due to heat expansion. Anyhow, i cranked the rod shorter again, and they seem fine now... anyone ever have this problem? (I know i shoulda started a new thread, but since everyone around here seems to read everything anyhow, i'll just ask here. Thanks!

Joe. Do you know anything about the torque converter in your roadster? Has it been rebuilt? These can be a cause of driveline vibration also. Some converter rebuilders do not do a good job balancing these once they have been rebuilt. If you can't find the cause of the vibration, you may have to remove the converter to flexplate bolts and slide the converter back and check to see if the vibration goes away. This will tell you if it is in the drivetrain or the engine.

Originally Posted by C9x

I'm glad to see that I'm not the last rod builder who prefers throttle rods instead of cable.

I too prefer the rod ...



It was the only way to do it back when I started ... and I just never saw the need to buy a store bought cable thingie when I could make a rod up easily. I do paint mine " Discreet BLACK "

Originally Posted by DennyW

I like your trans kick down switch also.

Thanks ... the factory ones for a Turbo 400 are so large, bulky and unsightly ... mine is a little home made bracket with a Jones-Lambson switch