DIY Automatic Transmission Hose (Upper) Replacement

[jreed]

My upper transmission hose developed a leak several years ago (at ~130k miles). It showed up as a slow seeping of ATF from the lower crimp, large enough to keep the metal line below the crimp wet with fluid.
The upper transmission hose is apparently the less common one of the two hoses going to the transmission to develop a leak, but I'm not the only one who has experienced it.
I am grateful to the advice that was posted here about transmission hose leaks, parts sources, repair options, and how to replace leaking upper transmission hoses:
https://www.matthewsvolvosite.com/forums ... 0&p=270124


In the photo below you can see the two hose clamps I installed a while ago on the crimp to try to slow down the leak -- the hose clamps did not have any effect. The photo was taken after removing the battery and the battery tray (and disconnecting the cruise control pump under the tray), which was helpful to get access to the hose.

Overview of area after removal of battery and tray

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After keeping an eye on the leak for a while and worrying about it, I decided to go for an OEM replacement hose, mainly for peace of mind. I figure if the leak became large it would allow all or most of the fluid to leak out while the car was running and then potentially allow the transmission to overheat or be damaged… an expensive problem. The Volvo replacement hose cost about $90 from Waltrip including shipping. Note that this hose is the AT fluid outlet hose: it connects to the lower part of the transmission and the upper part of the radiator.

The part number is 9180542 (note this is the part number for model years up to and including 1998)

Upper transmission hose part 9180542

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The first step is to clean up around the top and bottom hose connections and the nearby areas so you avoid getting any dirt into the transmission. Then I used a pair of snap ring pliers to remove the clip. These little pliers made the job a lot easier than prying with a screwdriver or using needle nose pliers (both of which I have used in the past when doing fluid changes).

Clip removal with Snap Ring Pliers

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Once you get the clip off at the top, the upper hose will pull straight out from the radiator.

Upper hose loose

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Next you have to remove a bolt that holds a support clamp about half way down the solid metal part of the line. This bolt is difficult to reach. From below the car I used a slim flexible wrench with a 12mm 6pt deep socket to break the torque and loosen the bolt. Once it was loose I removed it with the finger tips on my left hand, which could just barely reach between the subframe and the transmission. If I had to do it again I would break the torque from below but then loosen and remove the bolt by reaching down from above in the engine compartment.

Slim long-handle flex-head ratchet (useful tool!)

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Then I cleaned up the lower connection again to remove most if not all of the dirt and grease around the bolt and tube.

Area around lower tube cleaned up

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Then I loosened the bolt with a 10mm socket.

Loosening bolt with 10mm socket

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I placed a catch pan under the connection, expecting a lot of fluid to drain out once I removed the tube, but it didn't happen that way. Only a small amount ( about 4 ounces / ~100 mL ) drained out.

Disconnected and draining (a small amount of ATF)

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One thing to watch out for when you remove the tube: make sure the o-ring comes out with the tube, and if not remove it before installing the new tube. When I pulled out my tube the oring was left behind in the body of the transmission… You can see it in the picture below:

Old O-ring is still captured inside hole -- need to remove!

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I removed the o-ring with a pick tool, trying to be careful not to scratch the surface:

Using pick to lift out old o-ring without scratching metal

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I wiped out the opening with a towel to make it as clean as possible.

Once you have the upper and lower connections loose, and the mid-way bolt removed, you are ready to remove the old line. I pulled it out from the top of the engine area. I made a note of how I had to twist, turn and slide the hose while removing it because I figured the new one would have to be installed with the reverse motions to get it snaked back down into the correct position. This turned out to be almost true.

After getting the new hose jammed in a time or two, I figured that the protective cap on the end of the new tube (which was not present on the old tube) might be preventing the passage of the new tube down into position. I clipped off the top flange of the protective cap to make it narrower (see image below).
I also compared the old hose with the new hose and found that the new hose has a slightly different bend pattern than the old hose (both hoses are OEM, just one was made in 1996 and the other in 2012). You can see in the image below that there is a subtle difference in the bend path between the two hoses -- the old hose has a sharper bend than the new one:

New hose (left) and old hose (right), side by side, showing the sharper bend in the old hose. Installation of the new hose is slightly different than the old hose because the bend is different.

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Installing the new hose was a little more difficult than the old hose. I had to snake it in from the top and then go down below and guide it into position, with a couple iterations, until I got it right.
Snaking it in from the top (orientation seemed to be critical):

Snaking in the new hose. The starting orientation and sequence of turns seemed critical. You can practice on the old hose a time or two until you get it right. The new hose goes in almost the same way.

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And finally getting the hose positioned at the bottom:

The cap has been clipped to allow it to fit between transmission and sub-frame. You may have to alternate between pushing and turning from above in the engine compartment and pulling and turning from below near the transmission.

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Then I connected the tube to the transmission… I removed the protective cap and lubed the new (green) o-ring with some fresh ATF (I used Castrol Dex-Merc fluid)

O-ring lubed with fresh ATF

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Then I installed the bolt and tightened it up… no torque spec. I just tightened it up by hand using a 'reasonable' amount of torque. There was no old thread locker on the bolt when I removed it and I didn't apply any when re-installing.

Back up top, I cleaned out the fitting at the radiator and lubed the o-ring and the transparent plastic spacer on at the upper end of the line:

O-ring and spacer at top lubed with fresh ATF

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I was a little curious about the transparent plastic spacer on the new hose, so I did a side-by-side comparison with the old line. The old line had the spacer (a little yellowed after years of use) too:

New hose (left) and old hose (right) side by side. Both have a transparent plastic spacer.

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Then I inserted the upper end of the line into the radiator connection:

Upper hose inserted into radiator.

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And installed the clip by spreading it and sliding it on. Note that the connector is asymmetric… the wider flange is flared and must go towards the radiator.

Installing clip by spreading and sliding it on and over the connection. Note the clip has an orientation -- the flared end goes towards the front of the car.

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I installed a couple of tie-wraps around the clip to hold it securely.

Next you have to install the bolt mid-way along the new line. From the top you can reach down and around the black plastic case on the front of the transmission and get the bolt started and partially tightened. This is a difficult step to photograph. The blue tip of my gloved hand at the center of the photo below is at the bolt location. Access it limited: I pretty much had to do it by feel and glimpse.

Installing the line support clamp bolt by feel

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Once you get the bolt installed and mostly tight, I found it easiest to go back underneath and tighten up the bolt from below. Visibility here is also limited. If you have a slim flexible wrench and sockets you should be fine. Possibly a flexible-head ratcheting 12mm wrench with a long handle would also work, but I found the offset provided by the deep 12mm socket was helpful to provide clearance.

Tightening up the clamp bolt with a slim flex-head long handled ratchet and a 12mm 6pt deep socket.

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Then I measured out the amount of fluid that had been caught in the drain pan and found about 3 ounces. I was surprised how little had drained -- I had purchased a larger quantity of DexMerc in anticipation of having to replace several liters of fluid.

I figured about an ounce more than what I caught must have been missed or wiped up and absorbed on a towel or rag, so I added back 4 ounces of fresh fluid, filling through the transmission fluid dipstick in the usual way.

Funnel in place to add ATF back through the dipstick hole.

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I did this repair three days ago and so far no leaks and all is well.
Good luck!

[cn90]

Thanks jreed,

I have leaks in BOTH hoses (Upper and Lower), each hose is $85 + shipping cost from Volvo.
I cannot justify to myself spending $170+ on these hoses, so.....

I will replace them soon but will re-use the factory hose metal fittings:
- Cut and remove the crimp area.
- Install generic trans hose.
- Use new clamps.

So my total cost estimate will be less than $10.

These hoses don't hold much pressure at all, maybe around 5-10 psi and that is it.

I will update this thread later with photos.

[jreed]

Thanks for the feedback... Your approach sounds like it will work and you're going to save a lot of money, which is great!

In my situation the car is driven by my wife sometimes on long trips, so it seemed to me that putting in an OEM part was the best move for me. The OEM part lasted for 130-160k miles and about 16 years, so hopefully I won't have to worry about or pay any more attention to this new hose for many years and miles to come.

[cn90]

I know the ATF is many vehicles carry low pressure because I looked it up the pressures.
Also in my 2007 Honda Odyssey van, the ATF hose is a plain hose that attaches to a nipple on a radiator with a simple clamp.
Volvo engineers overkilled with this hose!

[wheelsup]

Volvo over engineered a lot of stuff 20 years ago. Not sure what it's like now though. Stuff that used to be metal is now plastic and so forth.

Great writeup OP, excellent pictures.

[cn90]

I just want to add a few quick notes for those who want to replace only the O-rings:

- O-rings 6842413 (radiator side) and 968757 (trans side)...$3/each should be replaced.
- The "Sealing Ring" 6842414...$4/each is basically a "shock absorber" to prevent damage to the radiator as the hose sways back and forth when the engine runs. The sealing is accomplished by the O-ring mentioned above and not by this "Sealing Ring".
In most cases, the "Sealing Ring" can be re-used. Of course, it is your choice to re-use the "Sealing Ring" or not.
If you want to save $8, then re-use the "Sealing Ring".

- The Clip has a WIDE side (radiator side) and NARROW side.
It is very easy to make this mistake, and if you make this mistake, the hose will not "click" into the clip ---> hose comes out later causing massive ATF fluid loss. This happened to me a few years ago when my mechanic changed the Rear Main Seal, during install he reversed the clip w/o knowing it. I lost tons of ATF on the highway, scary experience!

- So the bottom line is:
* Install the clip with proper orientation.
* Wrap a screw-type clamp around the clip to secure it.

PS: Those who want to flush the ATF, search for the DIY by "MadeinJapan".

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[cn90]

For those who want to rebuild the hose yourself, here is the tip using cut-off wheel, new hose and clamp.
The whole thing should cost less than $10 (the cut-off dremel wheel or angle grinder is about $20 tool at hardware store):

http://www.starquestclub.com/forum/inde ... pic=125941

----------
DIY using new hose and clamps. This will cost less than $10.
- Get an angle grinder at hardware store for $20. Wear goggles and grind the metal crimp on the line, taking care not to damage the barb fitting and the round metal line.
The key thing: don't cut all the way through the crimp, when it is getting to 90% finish, use a pair of cutting pliers to cut it.
- Install new EPDM hose with appropriate I.D.
- Use 2 clamps on each end and loosely attach them first, make sure you can rotate the hose with respect to the barb fitting for now.
- Install the hoses.
- Do the final tightening of the clamps in the car so the orientation of the fitting is correct.
- This technique works when you deal with system with pressure less than 200 psi, which is the case here.

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[cn90]

This is an entertaining video to see: garden hose (probably single-ply and not the triple-ply) and a single Oetiker clamp.
The hose starts to leak at 23 bar (above 250 psi) at the other end, not at the end with the single Oetiker clamp:





With the exception of the hose from PS Pump ---> Steering Rack which carries very high pressure (10,000 psi etc., therefore for this hose buy a new one from dealer), you can rebuild your other hydraulic hoses as I mentioned above because:

- Notice the video above: single Oetiker clamp can easily handle 300 psi. When rebuilding your own hose: use 2 clamps.

- The EPDM transmission hoses you buy at the auto parts store can easily handle pressure up to 400-500 psi. Just read the package information. Good Year Trans Cooler Hoses have a burst pressure of 1,000 psi:

http://www.goodyearep.com/productsdetail.aspx?id=10534

- The operating pressure of:

1. Auto Trans Cooler line is about 5-15 psi or so, way below burst pressure.

2. Turbo Oil Cooler lines is about 10-70 psi or so, also way below burst pressure.

3. PS Return Line: 30-40 psi.

Now you can see that you can rebuild your hydraulic hose for some $10.

[jreed]

For reference the outer diameter of the rubber section of the upper automatic transmission hose is 16mm (measured by calipers, which matches what is printed on the exterior of the rubber "9.5 x 16mm") and the inner is listed as 9.5mm. I didn't cut into the hose to verify, but the odds are that it is 9.5mm.

9.5mm inner diameter and 16mm outer diameter

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[matthew1]

Jreed, missed this two weeks ago... now scheduled for VRD inclusion. Very nice DIY!