OH NO!!! tranny intercooler failed and created a catastrophe!!!

[pilot_man_dan]

My wife was driving on a highway doing about 55mph when she said it slipped out of gear and would not accelerate. She was able to pull over and call me. She said the transmission was in D, but when she pressed the gas it was as if the car was in neutral. I asked her if she could shift into 2 or 1, and she said she physically could not. She could shift into reverse, but it still wouldn't move. Eventually she was able to get it to limp off the main highway. She said she couldn't go any faster than 15 mph.

When I got there I saw a decent sized puddle of what appeared to be foamy tranny fluid on the ground, but it wasn't under the transmission - it was dripping from the front right of the vehicle. It was coming from the engine coolant overflow bottle.

I had it towed to a local tranny shop, and they told me the transmission intercooler had a crack in it somewhere, and it leaked into the radiator, causing trans fluid and antifreeze to mix. There is trans fluid in the cooling system, and antifreeze in the transmission.

They are replacing the radiator and performing 4 flush and fills of the transmission and the engine. They say they can get the car back up and running again, but because of the ethylene glycol getting into the trans, it will attack the clutch plates and eventually the transmission will fail.

my questions to you:

Any of you heard of this happening? The guy at the shop said it's common, but this is the first Honda he's seen with this problem.

What are the chances of my transmission failing quickly? I'm worried it will start slipping and I'll have to pay for a full rebuild (which is not cheap!). Any insight on this?

I'm thinking about trading it in and letting it be the dealer's problem! I've been thinking about getting into an 08-10 Pilot for a while now anyways

[rocky]

Yes there are threads with this reported. Sorry to say but you now hAve a high chance of tranny failure.

[jl_ss]

Happened to our 2005 25K miles ago. No problems since.

[pilot_man_dan]

@rocky

i searched piloteers for threads on this but i didn't come up with anything. do you have any links you can share? thanks!

[rocky]

Using radiator in the search function, and not going back too far in time, brought up many threads. Have selected these for you.

Help!!Transmission Issue Help!!!

Help! Possible Transmission Problem

Might be worth posting in those threads requesting a follow up from the OPs

[onu2002]

How and why is it possible for the two fluids to mix?

[jl_ss]

Originally Posted by onu2002

How and why is it possible for the two fluids to mix?

Bad design. Both antifreeze and tranny fluid run through the radiator to be cooled. Apparently seperated only by a thin wall at some location that is subject to corrosion.

[jl_ss]

Originally Posted by rocky

Yes there are threads with this reported. Sorry to say but you now hAve a high chance of tranny failure.

It is dependent on how early it was caught, whether it was run to the point that there was no movement due to clutch slippage, and how soon the fluids were removed.

Ours was caught immediately and not driven to the point of slippage. Wife noticed the puddle start as she was exiting the Pilot at a store. She then drove to the Honda dealer which was 1/4 mile away. The fluids were immediatley flushed multiple times. Best case possible. Haven't had a problem with the tranny since.

[krazykarguy]

It's not necessarily a "bad design", as just about every automatic transmission-equipped car I've worked on in the last 15 years has utilized a portion of the radiator to cool the transmission. It's an industry standard practice.

I would say that this type of failure can be chalked up to not enough failure testing 10 years ago when the Pilot was initially being torture tested.

Nissan has had a bunch of identical failures with the Xterra.

[theirishscion]

Originally Posted by jl_ss

Bad design. Both antifreeze and tranny fluid run through the radiator to be cooled. Apparently seperated only by a thin wall at some location that is subject to corrosion.

Yes, probably one of the better arguments for changing your engine coolant on time. Also perhaps an argument in favor of changing the 'it doesn't exist' ATF filter that's in the return line from the radiator, try to keep back-pressure in the radiator low. This happened on our 1983 civic, and the transmission ran fine for another 10+ years after it was repaired, albeit with fairly low annual mileage.

If concerned, I wonder if a super-aggressive ATF changing schedule for 30,000 miles after the incident might help avoid a failure, or is it too late the moment the friction material is exposed?

[pilot_man_dan]

Originally Posted by theirishscion

If concerned, I wonder if a super-aggressive ATF changing schedule for 30,000 miles after the incident might help avoid a failure, or is it too late the moment the friction material is exposed?

the mechanic i spoke with said once antrifreeze gets in the transmission it does damage immediately. he said it's not a question of if the transmission will fail, it's a question of when

[jl_ss]

Originally Posted by pilot_man_dan

the mechanic i spoke with said once antrifreeze gets in the transmission it does damage immediately. he said it's not a question of if the transmission will fail, it's a question of when

Going on 30K additional miles without an issue since it happened.

[jl_ss]

Originally Posted by krazykarguy

It's not necessarily a "bad design", as just about every automatic transmission-equipped car I've worked on in the last 15 years has utilized a portion of the radiator to cool the transmission. It's an industry standard practice.

I would say that this type of failure can be chalked up to not enough failure testing 10 years ago when the Pilot was initially being torture tested.

Nissan has had a bunch of identical failures with the Xterra.

I'm not saying using the radiator to cool the transmission is bad design. The bad design is allowing an area to be thin enough to corrode and allow the fluids to mix in the 100K mile time frame. Especially when it has the potential to take out the tranny.

[theirishscion]

Originally Posted by jl_ss

Going on 30K additional miles without an issue since it happened.

The information contained here; Automotive Questions and Answers - while getting a bit 3rd hand, seems pertinent. It sounds like once you've got some antifreeze in the system, you're potentially in real trouble. Of course, the friction materials Honda use in their rather unusual transmissions are perhaps not subject to this sort of degradation, who knows. I wouldn't bank on that though.

In case that link breaks, I'll post the meat of it here;

This was enough of a problem that GM issued a TSB, number T-93-107 dated June, 1993, on dealing with the problem. From the bulletin:

Models Affected:
All 1993 And Prior Cadillacs With Automatic Transmission

Antifreeze contaminated transmission fluid will cause friction material breakdown and seal degradation. The binder in friction material may dissolve causing material to flake off.

Just changing transmission fluid is not acceptable. Friction material and seals that have been exposed to antifreeze, even for a short time, will eventually show damage. The torque converter cannot be completely drained so contamination would still be present when the remaining fluid circulates through the transmission.

If fluid is contaminated with antifreeze:

Locate source of leak and repair/replace radiator as needed.
Replace transaxle with SRTA or completely overhaul (including ALL internal/external seals and friction material).
Replace torque converter. The torque converter may contain friction material that must be replaced.
Flush transmission cooler as directed in Service Information Manual.

If it were my car, and I was out of warranty, I'd be inclined to have a super-aggressive flush done immediately. Then drive 100 quick miles and have a 2nd flush done (and yes, I'm aware Honda recommends against transmission flushing, but in this case, it sounds like the real goal is to get as MUCH of the contaminated fluid out as is humanly possible, and a hot flush on a machine is surely the best way to do that short of tearing the transmission down.) Probably best to flush with plain ATF, no special cleansing additives, since we're just trying to displace as much of the old fluid as possible.

Just a thought, anyway.

[qwikz74]

Originally Posted by theirishscion

If it were my car, and I was out of warranty, I'd be inclined to have a super-aggressive flush done immediately. Then drive 100 quick miles and have a 2nd flush done (and yes, I'm aware Honda recommends against transmission flushing, but in this case, it sounds like the real goal is to get as MUCH of the contaminated fluid out as is humanly possible, and a hot flush on a machine is surely the best way to do that short of tearing the transmission down.) Probably best to flush with plain ATF, no special cleansing additives, since we're just trying to displace as much of the old fluid as possible.Just a thought, anyway.

I would do this myself a few times just to get everything out of the torque convertor maybe even less then 100 miles. Pain in the butt but luckly it isnt that hard on these things. Make sure your using the Honda ATF fuild.