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Need another inch............

5K views 47 replies 15 participants last post by  Jebchevelle 
#1 ·
No...that's NOT what she said last night...0:)

I had a driveshaft made 2 years ago, after the stocker exploded through the traps at the track...

Ever since, it's had a mild vibration.
I "assumed" that I had simply hurt something else, and just lived with it...

Long story short....

Spline engagement at transmission yoke is barely over an inch, taking into consideration the shaft's length in regards to the seal...and has 1-5/8" of travel between where it is at ride height, and where it is when fully inserted onto the output shaft.

So, I think I'm about an inch short on total length, namely output shaft spline engagement ???

It doesn't even appear to be fully inside of the tailshaft housing bushing...

I have 2 options, I THINK....

One is to have/buy/make a 1" longer slip yoke, which is obviously the cheapest "fix"...

OR...

Another custom built driveshaft...

Has anyone here been in this predicament?

My yoke's length (just the part that slides through seal) is roughly 3-5/8", but I have seen one, while searching, that is 4-5/8"

Would that safely CURE the problem of my total length of driveshaft being 1 inch short?
 
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#2 ·
Seems to me that if you have been racing with the "short" driveshaft as it is that the longer slip yoke would be a logical improvement.
OTH, since you already had a driveshaft explode on ya - you know the correct fix..
 
#3 ·
It's actually been amazingly smooth, considering it has been this way since (I just checked) July of 2014... :surprise:

I'm leaning towards a new yoke, because there never seemed to be any problem, aside from a mild vibration...I should have taken a quick video of the movement it has, when all bolted up and car on a drive-on lift...
 
#4 ·
Unrelated question:

Notice from your signature that you once used a QFT SS-830. Do you have that carb available for sale?
 
#11 ·
I believe their website said they were 4-6 weeks behind? I can't wait that long....

In other news, I pulled the tailshaft housing off to check the bushing, and the egg shaped output shaft bushing fell out with it....now I get to yank the old Turbo 400 out once again...

Stopped at my transmission guys shop and he said it's an easy fix, but tranny has to be completely disassembled to replace it....

I have a new Spicer 1 inch longer yoke coming. That will put the yoke fully engaged into the tailshaft housing bushing, but not bottomed out.

Looks like I will still be back together and able to make the Outlaw Streetcar Shootout, so I may also swap in a looser converter...while it's apart again....
 
#12 ·
I got my Strange driveshaft thru Summit...had it in about a week. I was sweating the measurement thing till it was installed and sitting on the ground....my measuring skills are not good most times. :)
 
#14 ·
Bob,I might have mentioned this before,but have you ever had any dealings with Ron Hash?He's the driveshaft guy right across from Md Performance,called Perry Hall Power Equip.Ron is a little quirkey,but no one knows drivelines like him.He would be a good guy to talk to about drive line issues.
 
#18 ·
Bob,

I might be wrong here but I thought you can remove the tail housing from the transmission and then replace the bushing. It has been a while that I worked on a TH 400 but I think there is a snap rink holding the housing even after the bolts are removed, you can compress it at the tangs and the housing slides off.

I also had to buy a new, longer shaft when I recently switched to a 9" Ford.
 
#19 ·
This is not the tailshaft housing bushing...that one is actually fine, and still where it is supposed to be.

This is actually a transmission housing bushing for the output shaft itself that somehow dislodged from the housing...trans guy said I was lucky I didn't destroy the whole transmission...

I didn't see (in video) this until I climbed under to remove the tailhousing...



What blows is that I have THREE lifts, but all were tied up, so I started, what should have been a simple job, on the ground, using jackstands, and now I get to drop it back down, so I can spin the car around on GoJacks, and push it to one of the lifts after work today...lol.

.
 
#20 ·
OK, my bad I misunderstood you.

Anyway, at least it is a cheap fix although labor intensive. I got mine apart as well, in the process of installing A/C. One of theses days I just drive it more then what I work on it and sink money into it.
 
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#21 ·
I know this has been sorted - but just a comment on getting a driveshaft manufactured for any that may have the need. I purchased from Precision Shaft Technologies in FL. Great customer service, fast turn around and nice piece (and price). Check out yellowbullet.com for - I would venture to say 100% positive comments/reviews.
 
#23 ·
Their prices look very encouraging. Thanks for the tip.

When you (or the shop) change out the bushing, fit the "top hat" style version of that bushing. The standard design output shaft bushing has a propensity for working its' way loose in the Turbo 400. The flange on the top hat bushing prevents that.
You don't happen to have a brand name or part # by some chance, do you?
 
#25 ·
I actually got one of those, and it is sweet looking....but I found there's another issue...

Just left the driveshaft place, and the transmission place, dropping stuff off...

The problem is, I have a truck transmission, with the threaded hole on the output shaft, which originally used a stationary transmission yoke.

There is a raised "stop" that is actually part of the output shaft, that will not let any yoke slide on more than 3" from the very end

This prevents the "slip yoke" from having enough area for the yoke to slide

I had 1-5/8" total length from where yoke used to sit, to it being totally bottomed out, but still had about 1.5" of yoke tube showing.

SO....

The Turbo 400 is coming apart, hopefully today. Then I can go grab it, and get the output shaft's raised section machined down, so any yoke will be able to slide into the transmission fully...

Since the driveshaft is still too short, no matter what, as soon as transmission is back, then I can get the CORRECT "at rest" measurements, and get a new driveshaft made. I actually did go to the local guy, and he was OK TODAY....so, new tube, balanced, and the machining of the output shaft for 300, so guess that ain't too bad.....and surely could have been worse.
 
#26 ·
glad your getting it fixed, $300 does not sound bad around here it is $150 for a shaft if you provide the yoke and u joints.
 
#30 ·
That was what I had thought about doing myself.
The biggest there for me was the output shaft bushing was pushed out into the tailshaft housing.

It had to come apart and trans guy had an already machined output shaft.

I just got back from picking it up. Actually watched him disassemble and re-assemble it...Everything looked great, including the main housing, so I had a little good luck.

And I still may be able to use the nice yoke I bought... :D

Won't have the driveshaft until I get the trans back in and give him the actual measurements though. He said, probably Tuesday.
 
#31 ·
My th350 shaft bushing is showing signs of wear now so I know the pain had mine up on a lift yesturday and the new real seal is seeping checked shaft play and there is a little bit of play. I think if memory serves though I can just pull the rear housing ona short shaft th350 and replace it was gonna dig out my trans book to see. Glad you got yours fixed and it looked good other wise.
 
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#32 ·
You should be able to use a thin blade screwdriver and a small hammer between the seal lip and housing and it'll deform itself and pop out.

I can't finish mine up until midway through next week, but I also bought a new converter, since it was out anyway... 0:)

Should be a little quicker next time out, with the converter swap, and smooth running drivetrain, but we shall see.
 
#33 ·
I meant the bushing not the seal I just changed the seal when I got the correct lenth drive shaft. I was told by a friend the bushing can be changed without taking the trans out of the car on the th350.
 
#35 ·
yes I was reading my old tech manual and from what it looks like I will have to pull the trans out. I was offered a builder trans from a local scrapper might pick it up and rebuild it to go in I have not rebuilt a th350 in 12yrs lol did a th400 about 8 yrs ago so been a while if I had the money would get a trans from Jake shoe with converter, but just not that set right now. he is doing converter and trans packages now he had a nice th350 with a ultra bell I was gonna get for the vega but plans fell through on my end bills and what not.
 
#36 ·
Yes, i went with a longer yoke. Sonnax has a longer Yoke, very affordable and it is a work of art. Been in my car since this time last year with zero issues. I got mine from Summit. Search on Sonnax's website.
I too have a new Strange driveshaft that ended up being 1" too short. I have contemplated a longer yoke instead of having a new shaft built but I wonder if this is the best fix? Wouldn't it be best to lengthen the shaft to get the ujoints closer to the transmission to lessen the chance for vibration or am I over thinking things?
 
#37 ·
having it retubed is the best method but many have gotten away with using a longer yoke just rebalance the shaft with the new yoke or you will have vibrations.
 
#38 ·
Just to UPDATE:

~ Turbo 400 disassembled, replaced output shaft bushing, and output shaft was replaced with one that had the "stop" machined off of it...
All internals look like new (as they should after 2 months, lol)

~ New driveshaft made, new Spicer solid u-joints, one inch longer than the other.
Car has NEVER felt so smooth before...ever.

~ Since transmission was out anyway, I changed torque converter...
Had 2900-3300rpm 10" Transmission Specialties converter (aka Summit Nitrous converter, flashed to 3500-3600)
Now have 3700-4100rpm 10" Transmission Specialties converter (aka Jegs XHD converter, flashes to 5100-5300)

Head out yesterday to Test & Tune...and car launched great, sounded great, felt great, then blew a coolant hose "cap" off at top of 1st gear...actually split it, not blew it off... :(

Pulled to side of track as quickly as possible, but ruined the lane for an hour or so...felt like an ass, and a dummy for totally forgetting to drain and refill with water like I do every Spring...pissed at myself about that.
Installing some bushing plugs directly into manifold and water pump so that never happens again...

https://youtu.be/U7dbODSf0FQ

.

.
 
#44 ·
Bob
You and I must have the same kinda luck, last week on my way to the track the upper radiator hose collapsed. The day before I had driven it to the scales and left the radiator cap loose and it had spit coolant out but did not over heat just covered the windsheild on the highway at 90mph. I washed off all the coolant and made sure the cap was tight. The next day as I was driving to the trck the upper hose was sucked shut and would not come back to shape even when I tried to add water. I went to autozone as they are closest parts place and we could not find a prebent hose to fit the hose that was on it was a carquest part number and had been cut to fit. So I have a brand new flex hose as the upper hose. It fits great and has a spring so it won't collapse like the old one. It looks fine and does the job I refilled it with water I did the swap in the parts store parking lot lol they kept trying to get me to buy antifreeze as I kept filling a 16 oz water bottle from their drinking fountain I kept telling them the track does not like you to run anti freeze lol. Mine did fine after the hose swap never got above 195. Hope you have better luck then me next time.
 
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#45 ·
Yup, my luck sucks for the most part....I try to do stuff "right"...and, ya get used to having everything you do turn to shi#...but like my boss says..."There is ALWAYS someone who is worse off than you"...and that's 100% true.

In the overall big picture, I'm pretty pleased...my relief driver/mechanic just needs to be able to reach the pedals, and he's set. :smile2:

anyway...
Flushed it out thoroughly after work yesterday, grabbed some Redline Water Wetter, and 3 gallons of distilled water, plugged the intake and water pump threaded holes, and clear and non-slippery now...so there won't be a next time... 0:)
 

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#47 ·
Short answer:
I liked it last time I used it...

But, I honestly haven't used it in about 10 years.
The car I used it in (supercharged small block Ford) was maybe 75% strip, 25% street and it never, ever ran hot with straight distilled water and a bottle of the Water Wetter, so I really only added it this time because I figured it couldn't hurt.

This car is driven a lot more, so I'm curious to see if the results are the same as with a 50-50 coolant/distilled water mix (and 180 thermostat).
The car has always stayed right on 180* unless the AC is on, and I'm in traffic...then it'll creep up to 195-ish...then drop down as soon as the car was moving again.
 
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