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Need some help with leaky diff/vac lines at back of manifold


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Hey All,

Doing a bunch of work on the 955 CTT and ran into a couple of snags. 

First, this was my first time pulling the intake manifold. I mixed up some of the vacuum lines at the rear of the manifold. I can hear a loud hissing noise while the engine is running but all the lines are connected. Doing the coolant T's, I disconnect the gaggle of lines and Im 99% sure that at the end of a long day, I crossed some around. Does anyone have a picture or diagram of where the hoses at the back of the intake are suppose to be? 

Second, I am also doing a coolant flush. I drained it at the plug on the bottom of the radiator and caught 1.5-2 gal of coolant. How can I drain the rest from the block? When I bought the car, it started leaking coolant and I topped it off with several gallons of distilled water before throwing in the towel and having it towed. Therefore, I would like to drain as much of the system as I can and fill it with the correct dilution. 

Last one - I have fluid leaking at the input of the front differential. I have attached a photo of it as well. What's it take to R&R this one? On my last car (Audi), the diff output flange seals were the culprit for these kinds of leaks. 

Outside of that, it was surprisingly smooth sailing. Did the coolant T's, CET replacement, torque strut, and valve cover/spark plug/cam seals. The DIY articles here are very helpful! 

Thanks for the help guys!
 

File_000 (5).jpeg

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1 hour ago, dpatel710 said:

Hey All,

Doing a bunch of work on the 955 CTT and ran into a couple of snags. 

First, this was my first time pulling the intake manifold. I mixed up some of the vacuum lines at the rear of the manifold. I can hear a loud hissing noise while the engine is running but all the lines are connected. Doing the coolant T's, I disconnect the gaggle of lines and Im 99% sure that at the end of a long day, I crossed some around. Does anyone have a picture or diagram of where the hoses at the back of the intake are suppose to be? 

Second, I am also doing a coolant flush. I drained it at the plug on the bottom of the radiator and caught 1.5-2 gal of coolant. How can I drain the rest from the block? When I bought the car, it started leaking coolant and I topped it off with several gallons of distilled water before throwing in the towel and having it towed. Therefore, I would like to drain as much of the system as I can and fill it with the correct dilution. 

Last one - I have fluid leaking at the input of the front differential. I have attached a photo of it as well. What's it take to R&R this one? On my last car (Audi), the diff output flange seals were the culprit for these kinds of leaks. 

Outside of that, it was surprisingly smooth sailing. Did the coolant T's, CET replacement, torque strut, and valve cover/spark plug/cam seals. The DIY articles here are very helpful! 

Thanks for the help guys!
 

File_000 (5).jpeg

Welcome. 

Have a look at the below thread which I have loaded some pictures with notations to identify and locate the various pipe of the manifold and changeover valve (controls the divertor valves). 

Did you check the little one way check valves whilst you was in there? I mentioned which direction they work. 

 

Don't have any info on the diff leak but I do have a front diff bearing whine at speed around 120kph which I'm still looking for someone who stripped and replaced the bearing for some advice on feasibility of the DIY repair. If you do any work pls post info with pics thanks. 

 

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Those pictures are very helpful, thank you! I checked the lines and they are connected correctly. I can not see or feel any obvious leaks on the drivers side from where I hear the hissing. I have the sinking feeling that I will need to pull the manifold again. Maybe I did not get it seated correctly :/ 

 

I'll keep the thread updated about the diff. I also have some sort of diff noise but only when accelerating around 25mph. I plan on dumping a half bottle of Lucas oil stabilizer in with fresh gear oil. 

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1 hour ago, dpatel710 said:

Those pictures are very helpful, thank you! I checked the lines and they are connected correctly. I can not see or feel any obvious leaks on the drivers side from where I hear the hissing. I have the sinking feeling that I will need to pull the manifold again. Maybe I did not get it seated correctly :/ 

 

I'll keep the thread updated about the diff. I also have some sort of diff noise but only when accelerating around 25mph. I plan on dumping a half bottle of Lucas oil stabilizer in with fresh gear oil. 

Yes Likely the manifold gasket is not seated correctly. I assume you put new green gaskets on? 

Advisable to replace the throttle body gasket o-ring as well and give the throttle body a clean and alignment after clearing codes when reassembled. 

Have you checked your AOS and 3 way check valve works properly? 

 

 

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On 12/18/2016 at 0:39 PM, lewisweller said:

Yes Likely the manifold gasket is not seated correctly. I assume you put new green gaskets on? 

Advisable to replace the throttle body gasket o-ring as well and give the throttle body a clean and alignment after clearing codes when reassembled. 

Have you checked your AOS and 3 way check valve works properly? 

 

 

 

Yup, the intake gasket was not seated correctly! On the plus side, removing and replacing the intake is straightforward for me now. 

Thanks for the tip on the throttle body. I did that a couple of months ago when I purchased the CTT. 


Looks like the leaky seal on my diff is part #16 in the diagram below. Had the same issue on the input shaft of the rear diff in my Audi. Gonna mark up this project for a later date. 

 

 

 

Capture.PNG

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1 hour ago, dpatel710 said:

Yup, the intake gasket was not seated correctly! On the plus side, removing and replacing the intake is straightforward for me now. 

Thanks for the tip on the throttle body. I did that a couple of months ago when I purchased the CTT. 


Looks like the leaky seal on my diff is part #16 in the diagram below. Had the same issue on the input shaft of the rear diff in my Audi. Gonna mark up this project for a later date. 

 

 

 

Capture.PNG

Result! 

 

Let us know how the oil stabiliser works on the diff noise pls. 

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I put a 50/50 mix of Lucas oil stabilizer and gear oil into the front diff and it is quieter now.  Not gone entirely but the whirring/grinding noise on acceleration is much less audible.

 

It looked like my front diff had been flushed at some point and was overfilled. Hopefully that was the reason for the leak.  

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