61 GMC Hydramatic yoke

[padresag]

that what it says for the shifter; that loks like the name that they put on that' but it is still a hydramatic trans and not a hydromatic.
Hydramatic trans is a reg GM name
ron

[padresag]

Originally Posted by Str8axle

First pic: embossed on shifter mount

Second pic: tag on side of transmission case

My apologies to Surfdaddy. Didn't mean to hyjack your thread.

Let's look at it this way; Surfdaddy has a hydramatic trans in his truck. what you have is a hydramatic trans which was modified by B&M automotive and their modification has been branded "Hydro-Stick", but it is still
basically a hydramatic trans
ron

[Str8axle]

Originally Posted by padresag

that what it says for the shifter; that loks like the name that they put on that' but it is still a hydramatic trans and not a hydromatic.
Hydramatic trans is a reg GM name
ron

You're looking WAY to far into this. I never said that I had a "Hydromatic", I said that mine was a "Hydro" (meaning a B&M unit). Then, you asked for some proof of my claim. I merely answered your questions. I'm well aware of the fact that they are all Hydra-matics.

Evidently, I was misunderstood.

[padresag]

Originally Posted by Str8axle

You're looking WAY to far into this. I never said that I had a "Hydromatic", I said that mine was a "Hydro" (meaning a B&M unit). Then, you asked for some proof of my claim. I merely answered your questions. I'm well aware of the fact that they are all Hydra-matics.

Evidently, I was misunderstood.

i doubt it . you were using hydro referring to the yokes for a hydramatic

[Str8axle]

Sorry, never heard anyone say that they had a yoke for a "Hydra"...

[padresag]

tough to admit isn't it
ron

[Str8axle]

Whatever.......

Surfdaddy, good luck with your leak.

I'm done..
Posted via Mobile Device

[j.kirn]

Originally Posted by padresag

tough to admit isn't it
ron

you were both wrong right,

[padresag]

Originally Posted by j.kirn

you were both wrong right,

how were we both wrong?
ron

[MusicMan70]

how were we both wrong?
ron

Here's a Hydra; and a Hydro...

[Surfdaddy]

Well I got to look at the back of the trans this weekend. There is definitely a line about 1 ½ inches back from where the seal is sitting while the truck is parked. The yoke also seems to be pretty far out from the shaft and there is not a plug or seal on the back of the yoke. My guess is that the truck driving down the freeway or road is bouncing, (worn out rear shocks), and allowing fluid to seep by. That doesn’t explain the fluid leaking after sitting though. I’ll start looking for a new yoke and see if there is a plug that will come with it. I guess I should have taken pictures but didn’t think about it until now. I’ll try and get some tonight.

[padresag]

Originally Posted by Surfdaddy

Well I got to look at the back of the trans this weekend. There is definitely a line about 1 ½ inches back from where the seal is sitting while the truck is parked. The yoke also seems to be pretty far out from the shaft and there is not a plug or seal on the back of the yoke.

perhaps you should just undo the d/shaft at the back and see how far forward that you can push the yoke in. then pull it back about 3/4". that is where it should be sitting. possibility that the d/shaft is to short?. the yoke may not be entering the bushing. can you take a picture of how it is now?. these things are difficult to diagn without being there and seeing the whole thing . if it is a stock setup, there shouldn't be any problem with length. you never know though if someone has changed something and it makes it more baffling
ron

[Surfdaddy]

I’ll take pictures tonight. I feel pretty dumb asking questions without giving visual clues. When I had the transmission pulled I noticed that there wasn’t a bolt holding the yoke on the output shaft, and the yoke was allowed to move on the shaft. I asked on this forum and was shown by a number of people that this is correct. The front of the shaft is necked down like you would expect from a splined shaft and I thought that it should move in and out and the yoke on the trans should stay stationary. I’ll take pictures tonight and post later. The PO may have had the drive shaft cut since the truck was near the bump stops with a 1200 lb camper on it since it was picked up from the dealer's lot in 61 but that's taking a wild guess.

[padresag]

but then again one wouldn't think that anything is out of place. then again he may have buggered a d/shaft somewhere or sometime and found one that was close and put it in to get home and then never put it back the way it should. lots of scenarios with these old things
ron

[j.kirn]

Originally Posted by MusicMan70

Here's a Hydra; and a Hydro...

[Surfdaddy]

Here are some photos of the driveshaft and yoke assembly. As you can see the yoke seems to be out pretty far. I was thinking that there might be a slip joint where the yoke and the drive shaft are joined, since there is a Zerk fitting. I haven’t pulled the drive shaft to see if it moves or not.

[padresag]

that looks fine . just looks like the seal is leaking. whether it is the seal or the yoke at this point you will find out when you pull it out. I would just get a speedi-sleeve for the yoke when you pull it if it is required. they last for quite a while and buy you a lot of time to find another if needed. just micr. the shaft for the proper size ahead of time. they are not difficult to install
ron
http://www.skf.com/files/344136.pdf

[Surfdaddy]

So I went to put a new seal in and removed the yoke. The yoke looks too short to allow the yoke to move in and out on the output shaft. The drive shaft has a slip shaft in it and I don’t think both the yoke and the drive shaft should be allowed to move I think it should be one or the other. The drive shaft was very stiff and pulled all the way back which was pulling the yoke out of the seal. There is a threaded hole on the output shaft and it looks like the yoke should be bolted in place. The question is what thereads are this bolt. It looks to be ½-20 but the bolt won’t start. Anyone have this happen. Looking at the Hydra-Matic manual on line they call for a "special Bolt" I have no clue what that might be.

[Str8axle]

That's definately a bolt on yoke. I'll check my manuals and see if I can find the bolt size for you.
Posted via Mobile Device

[padresag]

then there should be a washer and a bolt that goes in there. the washer should just fit and it will be a fairly thick one(same as you would find behind a pinion nut. you may have to chase that thread with a tape in case it is buggered a little.
who took it apart?. you or the trans shop?. I would also give the yoke a little polish job and put a little lubrication on it when you reinstall it. I would also take that slip yoke apart and clean it up and grease it up so that it moves freely.
if you cannot find a washer, you may have to find someone to machine one up for you; thick enough so hat it doesn't suck in when you tighten it up.
I have an sm420 4 speed outside. will check in the morn if it has a bolt and washer similar to what you need.
ron

[Surfdaddy]

If I need to I can machine a washer. I found one that fits from Home depot but it’s not hardened or very thick but the size is right. The trans shop took everything apart and put it back together I gave them a master rebuild kit. I noticed the threaded hole and asked about it and how short the yoke was and how I couldn’t see how it could possibly seal if the drive shaft is moving back and forth. The guys at the shop assured me that this was normal and if things leaked they could seal everything with silicone. I went back once for a seal leak and they tried to charge me for it as well as adjusting the shift points (250 bucks) I told them that the adjustments and leaks should be under warranty which is why I took to a shop since I don’t have too much experience with rebuilding automatics. They did the work, under warranty, but the side seal still seeps, but I will never go back to them.

[Str8axle]

Did some checking in the manuals, nothing about bolt size. Maybe grab a tap set and see which one fits. That'll tell you your thread size.

[Surfdaddy]

After looking at the hole and thread I thought the size would be a 1/2-20 thread. The threads were petty messed up at the start point and I had it looked like the tap wouldn't work, I thought maybe it was a 1/2 -24 (hence the "special bolt"). So I went to Trans-Matic in Glendale and the owner had a trans in the back and pulled the bolt off and gave it to me. I checked it and it's 1/2-20 so I retapped the hole and that worked. So far no leaks. That also cured the vibration that would happen at higher RPM's. now that that's cured I have been able to notice a higher frequency vibration that is constant above 45MPH. It's not severe but I can fel it in the wheel (like a slight buzzing) and I can hear something but it's very faint. Maybe wheel bearings or something but I haven't been able to spend any time to figure it out yet.