Badly leaking 700R4 tranny- HELP !!

[Stroker-383]

Hi all,

 

Have got some bad news, was driving my 1972 monte carlo yesterday ( sunday ), and suddenly my tranny starts leaking badly !!

 

I stopped immediatly and checked the underside of the car. It leaked pretty heavy ... but i'm not sure where the transmission fluid is leaking from .... I think it leaks between the torque converter and tranny.... so i was thinking :

- Leaking tranny seal...

- Leaking torque converter ;(

 

I will disassemble the tranny this week to check everything... Hoping to find something that is wrong. (thats leaking )

 

Hoping to find some information about checking the gears properly and checking the fluid... Also i noticed my dip-stick to check the transmission fluid is a bit loose... so that needs to be fixed as well... ( thinking of the fact that the dip stick is leaking ... that can be the problem... But then it wouldnt leak so badly, would it? )

 

I will update here as soon as I've got news.

 

Wish me the best;)

[72MC]

I guess the biggest question I have is where is most of the evidence of new fluid showing up? Is it at the dipstick tube, the front pump, the pan edge, etc, etc? If I hear you correctly and it is dumping out, either the pan come lose or something broke structurally(ie., case, pump, convertor, input or output line, etc). I guess what I am saying is your definition of "leaking badly" is relative. Any pics?? - Dave

[7tonemonte]

It depends on how badly I guess, If its pouring out while its running from about the location your saying, Converter, a little less badly,maybe the front seal?

Either way, sounds like you will be pulling a tranny, best of luck with it

[502ci]

Quote:

Also i noticed my dip-stick to check the transmission fluid is a bit loose... so that needs to be fixed as well... ( thinking of the fact that the dip stick is leaking ... that can be the problem... But then it wouldnt leak so badly, would it? )

Sure it would if it's not seated properly...I'm hoping that's your problem so it will be an easy fix.

[Stroker-383]

Well, I've checked some things today .. While my brother was starting the car, i was checking the tranny etc.

 

When a gear is selected , ( Drive ), it leaks after about 2 seconds, between the torque converter en tranny.... So i pulled away the tranny and torque converter today ... but how can you see or suspect a broken torque converter or tranny...

 

The tranny was shifting as lightly as ever , so i dont think thats the problem. Also when i pulled away the tranny from the torque converter ( when the torque convert. was still attached to the startergear) It leaked oil immediatly, and heavy.

After pulling away the tranny and torque converter, i inspected the tranny.. I put it on the ground , facing the oil pan to the floor, and pushed the attachment side ( from tranny to engine ) , downwords , to check if the tranny is leaking ... this wasn't the issue so i'm thinking the torque converter is the problem.. How can i check the Torque converter?

 

pics coming soon

[7tonemonte]

I had one that was split in my old truck,I think the shop said it was a factory weld, under warranty so it didnt matter to me.

I dont know how to check them, I guess they pressurize it and look for leaks

[Grease]

The 700 has a bad tendancy to pop the front seal out . So bad in fact the factory makes a seal retainer . The retainer was there fix for the problem . When a 700 family trans is out and apart its common to drill the oil drain hole to a larger size . Sorry I dont have my nots handy just now or I could tell you the drain hole size recommended and the retainer part # . i can try to look them up tomooorow .

[Stroker-383]

I'm trying to replace the front seal of the tranny first... see if this will solve the problem...

 

@ grease : Thanks , that would be great!

[stangeba]

Check for a hole or crack in the converter. That's where my leak was albeit a TH350.

Good Luck,

Bruce

[Grease]

Stroker ,if I read my old reciepts correctly the GM part # for the front seal retainer is # 8654491 group # looks like 4.226 . I also use TRANSTAR parts and there part# is 61991 ,which you might be able to purchase at a local tranny shop if you dont have a GM dealer handy .

 

As to drilling the front seal oil drainback it can ONLY be done with tranny OUT and the PUMP TAKEN APART . In that case it would be drilled .281-.313 (9/32 - 5/16 )

[Stroker-383]

Hi all,

 

I bought a new front seal, ( where converter seals of on tranny gear ) here at a local transmission shop ... they have enough.

 

Also purchased the end gear seal ( from gearbox to diff ) Will try and mount those this weekend , and check if thats the problem..

 

Tranny shop says that i maybe need to use some filler rings or spacers to adjust the converter closer to the tranny, to let the seal, seal it perfectly.

 

[CrazyDavey]

Bram...there is no seal between the trans and the converter...both are self contained so I wouldn't worry about that....the converter should be bolted up tight to the flexplate...no spacers....Davey

[Stroker-383]

Well i've checked everything so far .. But got a couple of questions.

 

( Sorry for all the info I am asking for, I appreciate it very much, got a lot of reply's ! Thanks all in advance ) .

 

1)

First I pulled out the front seal , you can see this without seal on picture 1. There is a big aluminium ring inside of the oilpump. ( Pointed on picture 2 , with number 2 )

Picture 1

 

This alu ring is sticking out , about 2 mm.(0,079 inch), is this normal.. or do i have to slighty and gently tap it towards the gearbox so that it is even with the oilpomp edge? ( Check picture 2 - number 2 , where i've done just that ).

Picture 2

 

 

2) Second : I've checked the torque converter for any rough edges on the shaft that is going in to the tranny. So far i can't find any big damage or even small damage isnt there . ( See picture 3 & 4 and it's pointed out again. The number 3 , is where the seal from the tranny has been ( i think ) after blowing it out of the tranny fit number 4 ).

Picture 3

Picture 4

 

3) Third: Check picture 5, the rear seal ( As i called earlier : Seal thats between tranny and diff - i didnt know the name - Is leaking also... So i am going to change that to.

 

 

The seal is pointed out on the picture with number 5 written on it... The green arrows and number 6 , is :

- Is it normal that you can move the tranny axle up-down- and sideways ... (so in a radial way , not in a axial way) for about 0.157 inch ??

Picture 5

 

 

Hope that you guys can help me with this ... after knowing this i can build in the tranny this weekend ( sunday ), and driver hopefully on monday!

 

Best regards and thank in advance!

Bram

 

 

 

 

[Grease]

In the first 2 pictures where you are showing the bushing for the torque converter , DO NOT push it in . It is fine where its at . IF you push it in it could /will damage the pump .

 

In the last picture where you show the tailshaft seal(extension housing seal) ,yes the tail shaft (axle ) will move about with the drive shaft out . Once the drive shaft yoke is installed it locates the shaft correctly ,as the Yoke rides on the tailshaft (extensionhousing bushing when you should see once you remove the seal .

 

They ( tranny shop ) wouldnt/didnt sell you the seal retainer for the front ? You really should use one .

[Grease]

In pictures 3 & 4 the points(tips) of your arrows are showing where the pump rides on the nose of the torque converter . The 2 notched ( cut out ) spots are what drives the front pump . The wear marks showing where your #3 & #4 are is where the bushing rides . If you look slightly to the right of #4 there is a black line ,that is where the seal rides .ITs probly 3/4" from this line to the weld . That last 3/4" is where you may find slight rusting/pitting , because it is outside the seal and exposed to moinsture . Be sure to clean all the way to the weld and put light coat of oil or grease when you install into the new seal .

Aslo when you slip the comverter back into the new seal/pump make sure you rotate it and feel it engage the pump (2 notches). When its engaged correctly it should slide all the way in and have just about 1" of space ,when measured from a flex plate mounting surface ( the flat edge of the 3 mounting bolt towers)to a straight edge held across the bellhousing surface of the trans .Even the pilot stub should not touch the straight edge held across the bellhousing end .

Also like the tail shaft end it may seem a bit sloppy in the bushing . That is corrected when you bolt the converter to the flex plate .

[wallaby]

I agree, the seal rides much closer to the weld. Grease is right: you can see where the seal rides just to the right of your #4 in this picture.

Be careful when you install the new seal; you don't want to bend or disfigure it at all. Go around the edges with tiny taps to drive it slowly into place. Also when it comes time to install the converter, avoid letting the weight of the converter rest on the edge of the seal...get the converter all the way in before you stop supporting it.

[BowtieThunder]

I would venture to say if it was dripping oil then it has to be either the convertor seal or the pump seal thats leaking.If it was the convertor leaking or cracked it would be throwing the oil down in a line pattern

[Stroker-383]

Okay thanks all... So i will need to pull the bushing for the torque converter back .. about how far does it need to stick out??

 

What is there to damage .. the polyester / rubber white ring behind it , sits perfectly and has room...

 

Now i just need to find a way to pull the bushing back

[BowtieThunder]

No you dont pull the bushing back.Leave the bushing be.You have a leaking seal

[Stroker-383]

So the bushing can be left alone then :

 

I can leave it like this ? :

[Mike 57]

Yes leave it like that

[Stroker-383]

I think you misunderstood me :

 

The bushing WAS sticking out for about 2 mm.(0,079 inch) .. I tapped it inwords... as you can see on the picture..

 

So do i need to pull it back out .. so that it sticks out for 0,079 inch or can i leave it like this .. ( Tapped in ... )?

 

( Thanks !! )

[Winston Wolf]

It should look like this:

 

 

 

 

 

You may also want to get this to prevent seal blow-outs. The pumps can only take a couple seal installs before they won't hold it in just by the seal/pump friction fit.

 

 

Read this for converter position, you may need shims. I did.

 

The best way to be absolutely certain that the converter is fully indexed into the front pump is to place the transmission/converter assembly up against the back of the engine. The bolt lugs on the converter should not be touching the flex plate. There should be a gap between the flex plate and the converter bolt lugs. With the transmission bolted to the engine, this gap should be approximately 3/16” but no more than ¼”. (If the gap is larger than ¼”, precision shims must be installed to obtain the proper gap before the converter bolts are installed.). Before installing the bolts into the converter lugs you will need to slide the converter forward to the flex plate. If a gap doesn’t exist, the converter isn’t indexed into the pump properly. To get it to index into the pump, you need to continue turning the converter, at the same time, applying slightly inward pressure until it fully engages. Another easy way to check when using a full size converter is to try and slide your fingers between the converter and the pump housing. If you can, the converter isn’t fully engaged. This test doesn’t apply to the smaller v-6 or small diameter high stall converters.

[Stroker-383]

Thanks alot , that makes stuff a lot easier.

 

Looking at your bushing in the oil pump ... yours is even more tapped inside of the oilpump ... so i can just leave mine as is.

 

 

I will read the install manual properly for installing the torque converter. Thanks for info

[Stroker-383]

Hi all,

 

Well after putting it back together a couple of days / weeks ago.. It's driving like a beauty again! Had some problems with my tires , so had to get some new ones .. same size etc. ( I have more grip now! )