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Discussion Starter · #1 ·
My project vehicle has a 700r4. When the driveshaft was made up the first shop didn't do a very good job welding one end. The second shop fixed it but the total length ended up 1/2" shorter than what I initially wanted. The slip sleeve will go in 4 1/2" if slid in all the way. Once installed it's pulled back 3" to bolt it at the rear, leaving 1 1/2" engaged. Is this too little engagement??

Second problem. I noticed a puddle of tranny fluid below it today. It appears to be dripping from the front u-joint. The rear seal area appears to be dry. Is it possible for it to be leaking down the centre of the slip yoke?? When I unbolted it at the rear and shoved it into the tranny, fluid gushed out at the u-joint. The yoke supposedly came from an Astro van that was equipped with a 700r4.
 

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The shop that built my drive shaft built it with 3/4" clearance. Concerning the leakage from the front U joint, if the transmission was being filled for the first time and all the fluid was put in before the engine was started it will leak out as you described (this happened to me). For a TH350, TCI recommends adding 4 quarts initially then topping off after engine is started.
 

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Discussion Starter · #4 ·
Something else I just noticed. Not running the tranny fluid is over full and I think it looks a bit pinkish? Could it have antifreeze in it? Is my custom made rad from the local rad shop leaking into the cooling lines??
 

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murrsue,

I think there is an "O" ring that goes in the slip joint so the fluid does not leak out of the end of the yoke.

As for your question about the coolant getting into the transmission I would have to say no. The fluid pressures in the transmission are much higher than in the cooling system. So if your engine was overheating and leaking coolant out you would see the "scum" foaming out of your overflow tank.

Scholman
 

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murrsue said:
My project vehicle has a 700r4. When the driveshaft was made up the first shop didn't do a very good job welding one end. The second shop fixed it but the total length ended up 1/2" shorter than what I initially wanted. The slip sleeve will go in 4 1/2" if slid in all the way. Once installed it's pulled back 3" to bolt it at the rear, leaving 1 1/2" engaged. Is this too little engagement??

Second problem. I noticed a puddle of tranny fluid below it today. It appears to be dripping from the front u-joint. The rear seal area appears to be dry. Is it possible for it to be leaking down the centre of the slip yoke?? When I unbolted it at the rear and shoved it into the tranny, fluid gushed out at the u-joint. The yoke supposedly came from an Astro van that was equipped with a 700r4.

many ( not all) 700/4L60 trannys have a sealing sleeve with an O-ring in them . The yoke on the drive shaft will have a small hole in the center plug at the end of the yoke splines.

in the photo there is a sleeve on the out put shaft of the trans for the yoke.

:cool:

 

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1 1/2" slip is OK. The leak is probably due to a vent hole drilled in the welch plug in the slip yoke. This hole is there for late style trans with a sealed slip yoke "can". There are two waysto fix this. Install the yoke seal apparatus on the output shaft or weld the hole shut. Do not use silicone in th eyoke tube.
You CAN get coolant into transmission fluids thru the radiator cooler. If the fluid looks like strawberry milkshake, that is bad. One ounce of water in a trans will degrade the clutch bonding and the trans will fail. This is not a good scenario and there is no flushing that will cure the problem, only rebuild. This is not an uncommon problem in the trans repair field.... :(
 

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coolant in trans

I agree that you can bleed rad. coolant into trans.One possible way is when you shut off motor presure in trans goes away,but coolant presure stays up for a while.Also,I would want more slip area on yoke,may be OK tho.
 

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Tranny fluid leaking Thru the slip joint???

You can have fluid from the radiator leaking into the trans,yet still have no fluid from the trans leaking into the radiator, or vice versa.

This can happen because the surface tension is different between the two fluids.

Also chazmac is right, if this trans has water in it, it needs to come apart, before it comes apart.
 

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Every driveshaft maker I've heard of says this about driveshaft engagemen to the transmission. Push yoke all the way in and retract it 1(one) inch. Measure for your new driveshaft at this point. Your yoke is probably wobbing with output shaft which is deforming the seal lip and allowing fluid to leak.
It is new driveshaft time, pal.
 

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Discussion Starter · #12 ·
best way to check for tranny cooler/rad leak

I need to check the tranny cooler portion of the rad to see if it's got a leak. I was thinking about plugging one side and putting low pressure air to the other side and watching the coolant for bubbles. Sound good?
 

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trans cooler

Have worked in a rad shop,i've seen plenty cooler leaking.If your fluid look PINK AND FOAMY,you need a new cooler and poss. tear down of trans.I don't think your test will tell you more than just looking at fluid. real bummer tho!
 

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Discussion Starter · #14 ·
pink tranny fluid

Well I drained the tranny and the fluid is a milky dark pink. I disconnected the tranny cooler lines at the rad and hooked up some air at 15psi and I got no bubbling in the rad coolant at all. I left the pressure on and put the cap on the rad for a couple of hours and no pressure built up inside the rad that I could tell.
Now I'm left to wonder how the moisture got in. The 700r4 was used but was supposed to have been rebuilt with about 35000 miles on it. When I drained it last winter to install new wiring inside for the torque lock I don't recall the tranny fluid looking funny. The tranny sat empty attached to the motor in the chassis for a year until this winter when I put the truck cab back on. After I got it wired and fired up the motor I filled the tranny, a couple of quarts at a time while running the gear indicator up and down a few times. It's only been backed in and out of the shop a few times and then last week I drove it to the end of the block and back, up to about 30mph to see if it was shifting okay. It sat for a week until I noticed fluid coming out of the welch plug in the slip yoke and tranny was over full and pink. I guess I'm in for a rebuild now. Maybe I should have the rad rechecked at the shop that built it.
 

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"Don't need no V/8"-grandpaw
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flush

Do you have t/convertor drain plug,I don't think so.If its really milky then I would remove and flush t/convertor. Its hard to clean out when it mixes. Antifreeze does not play good with other things.
 
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