Question: Procedure to replace transmission cooler shut off valve on 1999 986

[DanaWDavis]

I let me son borrow my ’99 Boxster to drive his girlfriend around. Had to have it towed home the next day because it was spewing coolant. In fact, the whole system was drained. Got it home and traced the problem to what appears to be a ruptured automatic transmission cooler shut-off valve. Looks like the business bit is all plastic. This sits directly above the AT selector linkage. My manual, from Bentley Publishers, has no procedure on how to replace this thing. Looks to me like I need to remove support braces from underneath, and most likely the transmission selector linkage just to get at the thing. Would have been nice to be able to get at it from the trunk, but doesn't appear to be way. Is there a written procedure out there?

[illusionist]

Hello DanaW, did you manage to fix this? I have the same problem and would like to know how you got to the part. It seems to be a major PITA to get to from the top and I might have to drop half the car to get to it from the bottom....

[JFP in PA]

Fun to get at, but if not repaired, can kill the transmission. Fix it.

[illusionist]

Thanks for the quick reply JFP. There is no thinking about it, I gotta fix this because all the coolant is out. I think it drained 70% if not more from the leak...

Have you done this job? I dont want to tear apart the car if there is an easy way to do this...

[JFP in PA]

We have done several (we are a shop), none of them were fun. Easiest way is to pull the trans mount and lower the assembly slightly to make room. I have read that some people have changed them in place, but they must have very small hands and like to work without seeing what they are working on. Good luck..............

[illusionist]

Thanks JP. I will attempt this next week. Will post an update. Currently waiting on parts to come in from PP.

[illusionist]

Hello JFP:

I finally got the parts in yesterday and attempted the job today. I managed to get the old valve off and the new valve in (almost).

I removed the cross braces, metal plate, half exhausts and disconnected the half axle on the passenger side.

The problem I am running into is that the left side of the valve (input to the ATF cooler) is not completely snug with the hose. There is hardly any room to wiggle it into proper seating. I figure I'll have to drop the transmission a little bit like you suggested.

How do I go about doing that? So I remove both mounts or just the one on the passenger side? How low can I drop without wrecking havoc on all the ATF / Coolant lines and the electrical connectors?

Any help is appreciated.

Thanks.

[JFP in PA]

Originally Posted by illusionist

Hello JFP:

I finally got the parts in yesterday and attempted the job today. I managed to get the old valve off and the new valve in (almost).

I removed the cross braces, metal plate, half exhausts and disconnected the half axle on the passenger side.

The problem I am running into is that the left side of the valve (input to the ATF cooler) is not completely snug with the hose. There is hardly any room to wiggle it into proper seating. I figure I'll have to drop the transmission a little bit like you suggested.

How do I go about doing that? So I remove both mounts or just the one on the passenger side? How low can I drop without wrecking havoc on all the ATF / Coolant lines and the electrical connectors?

Any help is appreciated.

Thanks.

Both mounts have to come out, and you will need to support the engine and gearbox while doing that. You will then need to slowly lower the trans until you have enough room, usually just a couple inches at most(it will still be a tight working area, but manageable). As you will be working around what ever is holding everything up, think about its placement before you start as moving it after the mounts are out becomes a major pain.

[illusionist]

Success At Last...

JFP... Thank you my man for all your tips and suggestions!!!!

Couple of pointers for folks attempting this yourself:

1. Get yourself a set of hose clamp pliers. These look like regular pliers with a long cable attached to them. I picked up mine from Sears (Craftsmen).

2. You will need to remove the engine cover (from top), remove the metal plate, cross braces, sway bar, half exhausts and disconnect the passenger side Dive Shaft.

3. You will need to remove the Torx Bolt (#A in picture) to create some play in the metal hoses and this in turn gives you some room to work with.

4. Start by disconnecting the clamp to the right side of the valve (C), then proceed to remove the clamp on the left side of the valve (B).

5. Pop the old valve out and then fix the new one in connecting the left side first (B) and then the right side (C).

6. On my car, the cylinder of the old valve (D) was mounted vertically. This caused the cylinder to touch the chasis, which over time (and over bumps) caused the cylinder to disintegrate, apply pressure on the valve housing and caused it to crack (my guess). When I reinstalled the new valve, I installed it so that the cylinder (D) is horizontal.

I did not drop the transmission as I could not for the life of me, figure how to remove the passenger side mount.... I took me about seven hours, but thats because I tore up a CV boot and spent about 2-3 hours replacing that.

This is definitely a doable job, but make sure you have lots of beer nearby and a friend who doesn't take offense to your cusses. Good Luck!





Ps: why open the top engine cover? 1. For added lighting 2. I ran the hose clamp pliers from top and had a fried squeeze them while I positioned the latch from the bottom.

[JFP in PA]

Glad you worked through it, now go enjoy the holiday..........

[illusionist]

Ha! I wish... My holidays are spent working on the first love of my life..

JFP, I have one more question. I cant figure how to remove the transmission mount on the passenger side. The ATF cooler seems to get in the way of the third bolt (on top). But even if I manage to remove the third bolt, I cant remove the mount because the ATF cooler is in the way. Any tips how I could remove this mount?

I have a spare mount I purchased last year and could not swap the passenger side out....

Originally Posted by JFP in PA

Glad you worked through it, now go enjoy the holiday..........

[Sputbert]

Hi All, first post.
A friend brought his 1998 Boxster in for this repair. It turns out to be pretty simple:
Raise and support the car.
Remove the aluminum underplate, and unbolt the 2 bolts that hold the rear bracket to the trunk floor. This bracket won't come out, but you can move it one way or the other to improve access. Remove the E-clip on the Tip relay lever and slide the lever off the pivot pin. Remove the 2 T40 bolts that hold the relay lever bracket to the trans case. Remove the spring hose clamps toward the pipes (away from the valve.) Do all 4 if you can, but I couldn't get to the one on the front of the valve. Remove the vacuum hose from the pod at the top of the valve. Twist the valve a bit and it will come loose. It comes out with the relay bracket. Once out, find the single Phillips screw that holds the valve to the bracket and remove it. I had to whack the white side hose nipple to get the valve to pop out of the bracket. Don't worry, you're throwing the old valve away. The hoses are 18mm ID, available in bulk or for big $ from Porsche. Each hose is 50-60 mm long. installation is the reverse. If the clearance is really tight and you're worried about bending the pipes, slide the hoses onto the pipes first, then install the valve and slide the hoses into place. Silicone spray is your friend. This job can be done in less than an hour , not including fill/ bleed.