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yoke won't go all the way in


Kevin Wiles

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T-10 4 spd transmission (not super t10)

 

The yoke slides in and stops about 60% down.

 

A long time ago when i was measuring to shorten my driveshaft, I thought this must be normal. Since then I've driven very little and very lightly, because I know my driveshaft is too short... I wanted to get a new driveshaft and before I do that I'm investigating about this yoke issue first.

 

Now I've shown the yoke to a driveshaft professional and showed him the point at which the yoke is in the tail as far as it will go and he says thats just not far enough. My current yoke is wearing a notch in itself from the bushing because its not riding right.

 

So what could be causing this oddity? He gave me another yoke to try but my mind is working overtime, maybe this transmission takes some weird rare yoke or something. i'm such a pessimist. He said the yoke should slide in almost to the end of it.

 

Any help appreciated.

I need to get busy if this car is going to make it to the 10th anniversary FGMCC meet.

 

And if you're wondering why I dont just ask these questions to the so-called driveshaft expert, its because you have to tread so lightly around this guy, he's old and cranky and he'll get mad and bite your head of if you're not careful... but he's the best around with driveshafts so I'm just trying to get the most info as I can from you guys so I can learn up on the subject. Please help!

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Kevin, a t-10 tranny takes the same 27 spline yoke as a th350, t-56 and the 4l60. Can you see past the seal to see what is coming in contact with or just remove the "end cone" and see what the obstruction is. Is the yoke one of the longer version where the splines do not go out all the way to the end of the yoke. I have seen this in th400 shafts. The splines don't start until 1"inch in yoke. - Dave

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i tried another yoke to see what happens and it does the same thing, it will only slide in about half way. I took a piece of rod and stuck it in the tail of the trans and rode up and down to see if i felt a burr or any other obstruction on the tail shaft, but i didn't feel anything out of the ordinary. then i went around in circles with the rod inside the tail of the trans to see if there was something obstructing around the outer edges, but again i didnt feel anything. it has the course spline yoke and tailshaft. its not like a th350.

this trans does not have a little end cone to take off and view just the tailshaft area. anyone ever heard of this? and oh lord why me??? why me!!!??!??

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Kevin, it looks as if you DO have a tail housing that can be removed and leave the tailshaft sticking out in full view. It also looks like the yoke simply slips in as far as it goes and bottoms out on the speedometer gear or reverse gear....either way, the two gears are positioned on the output shaft by snap rings, and are non adjustable. There really isn't any way those gears could be installed wrong unless they are too thick and the rear snap ring was left out. The other possibility is the wrong length tailshaft housing?

 

If you measure the depth from the rear seal to the face of the gear inside the trans, does it match with the depth the yoke is going in? or is the yoke stopping before it gets that far?

Here is an explded view if it helps ya

http://www.nastyz28.com/tech/bw-t10.html

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i could stick a small screwdriver or a rod waaaaay up in there before it stopped.... on the other hand, the yoke goes in about 2" then stops. if you take a hammer and tap it it will go another 1/4" or so, but then you have to absolutely baat on the sucker to get it back out. ps my yoke is 4" long .....

 

and there is 1/2" of tailshaft sticking out of the back of the trans and that seems to be the proper amount so that rules out incorrect tailshaft housing. so to review if my yoke only goes in 2" and there is 1/2" of tailshaft sticking out, its bottoming out at about 2-1/2" total spline contact. if I pull it out 3/4" or 1" to prevent jamming and go like that, i'd only have 1-1/2 to 1-3/4" total spline contact. Something is just not right here. I'm afriad if i start tearing the transmission apart i'll be in over my head quickly and end up having to tow the car to the shop ($$$$)

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Hi Kevin, I ran in to this a long time ago when I put a T-10 in my 1967 Firebird that was from a full sized Chevy. I seem to remember there is a bushing that gets in the way. If I remember correctly it had to do with the two piece drive shaft that was in the big cars (maybe a slip yoke in the middle by the carrier bearing?)so the front yoke didn't have to go in as far. I ended up replacing the tail shaft housing and was able to use a normal slip yoke. I wish the details were clearer in my mind but it was 31 years ago. Lol David

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some yolks had to be bolted to the output shaft, then a slip yolk used or a two piece drive shaft, if this trans is from a pick-up truck, that might be the issue here

 

does the end of the output shaft have a threaded hole in it ???

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Alright, you tried two differnt yokes, and they both behave the same, so we can probably rule that out. My next guess is either a problem with the splines on your output shaft (a burr or dent) or the shaft itself isn't straight. I guess it wouldn't hurt to inspect the rear bushing to be sure it's fully seated in position and not slightly crooked.

 

So to sum up the problem; you have two yokes and neither one will slide all the way into the trans. If you apply force, the yokes will travel a bit further in (still not far enough), but then become bound up on the shaft?

 

I think you are going to need to remove the extension housing and really inspect the output shaft and see if the yokes slide over it when the extension housing isn't there.

It looks as if you just remove the speedo gear, undo the bolts that hold the extension to the transmission case, and then pull the whole extension rearward to expose the output shaft. It's that simple. Nothing is going to fall out except some gear oil.

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i am being told by another source i might have a twisted output shaft on the trans. and that this statement alone says twisted shaft:

 

Quote:
i could stick a small screwdriver or a rod waaaaay up in there before it stopped.... on the other hand, the yoke goes in about 2" then stops. if you take a hammer and tap it it will go another 1/4" or so, but then you have to absolutely beat on the sucker to get it back out.

 

how do I remove the tail housing and what should i expect, is this a fairly easy job or will i have to start dismantling things that i'll get in over my head.???

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I think you are going to need to remove the extension housing and really inspect the output shaft and see if the yokes slide over it when the extension housing isn't there.

It looks as if you just remove the speedo gear, undo the bolts that hold the extension to the transmission case, and then pull the whole extension rearward to expose the output shaft. It's that simple. Nothing is going to fall out except some gear oil.

 

 

I guessed a bent shaft, or buggered splines, but twisted shaft is a good guess also! Whatever it is, it sounds like it's going to be a problem with the output shaft.

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  • 2 weeks later...

UPDATE UPDATE UPDATE

The T-10 is getting a good rebuild

 

Small Parts Kit

Blocking Rings

Syncronizers

Gaskets

 

AND the big expense... A new main shaft.

 

Going to a 27 spline.

 

Should be out of the shop in a few days and then i'll install it back in its home in the coke machine a few days later. Then its all about getting a new driveshaft shortened.

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yes, bent main shaft

 

Seems to be a common problem on an already hard to find T-10 Main Shaft.

 

Found a box of T-10 parts at Super Chevy, same problem warped main shaft. crazy

 

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  • 2 weeks later...

got the tranny back from the shop and after a lot of screaming, kicking, and groaning, got it back in there installed. Now it has the same tailshaft spline count as a turbo 350. Took a stock monte driveshaft, and tried to test it out, but the front yoke balancer is hitting a part of the outer case of the transmission so to make a long story short i'm going to try another driveshaft today, one without a balancer.

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Correct me if I'm wrong but I believe the balancer is only there to help smooth out any drive line NVH (noise vibration harshness) making the Monte Carlo a step or two better than lesser cars of the day. Our cars also have rubber insulation pads for the rear transmission cross member, that lesser cars do not have. On your race car, it will never be missed.

Bruce

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got a normal driveshaft with regular yoke and found out it will need to be cut about 5/8" of an inch frown

 

This sucks, I was hoping that driveshaft would work. Atleast the 70's engine compartment is done. grin

 

I didn't know what was going on under the coke machine on saturday. i was asked to push the clutch in, then proceeded to hear screaming, moaning, groaning, whining, etc, etc. shocked

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ok in the end, I had to shorten a stock driveshaft 1-1/8". Its back in the car now, and I drove it for about 20 minutes yesterday. I'm getting a driveshaft loop tomorrow also, the one from metco motorsports.

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