Failed Transmission cooler

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Failed Transmission cooler

April 16, 2015, 09:38:29 pm

Well here I go again. Was traveling west on I40 jus oveer the Oklahoma line when I noticed the Allison was in 5th gear and would not shift to sixth. Stopped at the East bound visitor centre to check the tranny fluid WITHOUT shutting the engine off. Glanced at the coolant reservoir and saw red tranny fluid. Looks like the tranny cooler that was installed in Maryland last spring has failed, don't have but 5000 miles on the thing. I am in Oklahoma City at the Allison dealer. Really do not like this cooling configuration where they use the engine coolant to cool the transmission fluid. Will have to call Maryland dealer tomorrow after I confirm it is the xmission cooler that failed. This really rots.

Roland

Re: Failed Transmission coole

Reply #1 – April 16, 2015, 10:29:30 pm

Sorry to hear about this breakdown, Roland. At least you are not out in the boonies...

Re: Failed Transmission coole

Reply #2 – April 16, 2015, 10:31:13 pm

Ouch.

Re: Failed Transmission cooler

Reply #3 – April 17, 2015, 11:39:24 am

That is a bummer! Man, I hope you get this solved and can put it in the rear view mirror soon. To fail that soon... there has to be a reason. Maybe the mounting points are stressing the assembly (not enough give in the mounts?). I feel your pain!
Don

Re: Failed Transmission cooler

Reply #4 – April 17, 2015, 01:32:18 pm

Quote from: acousticart – April 17, 2015, 11:39:24 am

That is a bummer! Man, I hope you get this solved and can put it in the rear view mirror soon. To fail that soon... there has to be a reason. Maybe the mounting points are stressing the assembly (not enough give in the mounts?). I feel your pain!
Don

WHEW ESCAPED THAT ONE. Just talked with the technician, transmission checked negative for glycol. Would not shift into 6th because some plug came loose. The transmission fluid in the engine coolant reservoir came from the old transmission cooler that is can integral part of the original radiator. Technician thinks they probably did not or could not flush that section very well last spring when I had the original problem. All I could see when I got here were $$$$$ flying away. What a relief.

Roland

Re: Failed Transmission cooler

Reply #5 – April 17, 2015, 02:15:06 pm

GOOD NEWS!

Re: Failed Transmission cooler

Reply #6 – October 11, 2018, 03:20:49 pm

Appears the new transmission cooler that was put in four years ago has failed. If that is the case I've had it, just can't throw more $$$$ at this thing. I'm at another 10CB in repairs this year already and the money tree has shed it's last leaf.

So here is the symptom I'm getting. After parking overnight the transmission dipstick indicates a full level of fluid. Start and run the coach dipstick is dry. Transmission overheats in a very short period of time. No transmission fluid on the ground. Same symptom I had four years ago at 12CB to repair.

No more I'm done gonna get it to a salvage yard somewhere. A shame as I just put in 10CB already this year for the brake job and new tires. But enough is enough no more bleeding.

Maybe I could hope for a refrigerator fire.

Roland

Re: Failed Transmission cooler

Reply #7 – October 11, 2018, 03:25:19 pm

Sorry to read of more troubles.

Any sign of transmission fluid in the plastic radiator overflow tank?

Any codes stored in the trans ECU?

Where are you parked?

Re: Failed Transmission cooler

Reply #8 – October 11, 2018, 03:34:13 pm

Roland- very sorry to hear about your issue. The good news is that you have your place in Ajo now, so you and Carmen have a home. We were hoping to see you both at Quartzite in January, but it seems this might not happen. Maybe we can swing by Ajo sometime for a visit.

Maybe someone on the forum would like to buy your new tires and help you out a bit? Just a thought on how to make this better.

Best of luck Roland

Re: Failed Transmission cooler

Reply #9 – October 11, 2018, 03:47:16 pm

Yes, need more info to give reasonable advice:

Any sign of oil in the coolant reservoir (milky/cloudy)?

Any sign of coolant in the transmission fluid or is it still clear pink?

No first hand experience with the Allison 4 speed, but never heard of checking fluid with the engine off. Fluid level engine running, transmission in neutral and COLD will be lower than when warm.

Re: Failed Transmission cooler

Reply #10 – October 11, 2018, 03:56:10 pm

We are in Lakewood NM at an SKP coop park. Level in the plastic overflow tank is higher than it was before this happened. I was low on coolant but not anymore. I was hoping to see transmission coolant on the ground but nada.

HOW IT HAPPENED

Yesterday I drove eighteen miles to have new crossfires installed. Coming back I noticed that the transmission temp was very high. Checked the xmission coolant level and it was very low. Added a gallon with the engine off and it was not at the hot mark, but visible. I let everything settled overnight. Checked the level this morning and it showed full to the hot mark. Ran the engine engaged the transmission and sat there with the engine idling and the transmission in first for a few minutes. Put the transmission in neutral left engine running checked fluid dipstick came out dry. Checked level a couple hours later and fluid was at the full cold mark. Fluid looks clear. Kinda the same symptoms I had four years ago with a failed transmission cooler. Haven't run the coach any distance but with these symptoms I don't want to leave the campground to check anything further. Dipstick should not come out dry with the engine running with the transmission in neutral if stuff is working as it should.

Roland

Re: Failed Transmission cooler

Reply #11 – October 11, 2018, 04:17:03 pm

Roland,

Listen carefully to Brett. Yes, you may have an issue but perhaps not as bad as it seems. While I would not spend another $12K, I would look at possibilities before writing the coach off. If the cooler has failed, possibilities would be to drain the transmission and go to an air to air cooler and then changing fluid several times to make sure all coolant is out of torque converter and transmission. Sure is nice to have the coolant and ATF separated with no chance to mix.

Probably not that expensive to have it towed from Ajo to Puerto Penasco. Lots of mechanics there that can do work for a fraction of the price. Probably tow also for a fraction of the price. Glad to call contacts I have there if you might consider it.

I've never liked trans coolers but that's water over the dam now.

Good luck. Really sorry to hear this.

Pierce

Re: Failed Transmission cooler

Reply #12 – October 11, 2018, 04:24:51 pm

Roland,

I was thinking about something like this with an electric fan. 25-Row Dual Pass Fluid Cooler

or: 1030606-DS-12 - BD Xtrude Transmission Cooler with Fan - Double Stacked...

Mounting a trans cooler on the radiator face might be a good idea and would take advantage of the existing fan(s).

With your Allison locking up in the higher gears, not that much heat is generated except in first and part of second gear.

Pierce

Re: Failed Transmission cooler

Reply #13 – October 11, 2018, 05:21:42 pm

Roland sorry to hear about the problems, I had a silver bus with a 892 Allison 4 speed, and had a stand alone trans cooler with a fan and it worked great, just some food for thought. Good luck my friend.

Re: Failed Transmission cooler

Reply #14 – October 11, 2018, 05:48:02 pm

Roland, sorry to hear of your problems. I hope there will be an easy and not too expensive solution. Good luck!

Re: Failed Transmission cooler

Reply #15 – October 11, 2018, 05:59:59 pm

Roland, here is a picture of what is in our coach. I believe it is available from O'reilly's
The mount for the tranny cooling radiator is welded to the frame.

Re: Failed Transmission cooler

Reply #16 – October 11, 2018, 08:18:07 pm

Roland take the advice change the Trans oil and separate the cooler. You could bypass the cooler with the correct fluid level and take it for a short drive to verify the Trans is not damaged further then get an air cooler. Company near me makes cement mixers they have a fantastic fluid to air cooler made for high flow with large fittings. Look to see who makes heavy duty equipment and see if they will sell you a cooler.

Although if you do sell it for salvage I am imagining your coach going with a line up of parts scavenging foretravel owners in tow trying to get their wish list filled first.

Re: Failed Transmission cooler

Reply #17 – October 11, 2018, 08:55:37 pm

Wow! Sorry to hear Roland.

Pierce seems to have a good plan for you even if you don't jump right on it........not much deterioration of your FT in that New Mexico climate.

Good luck.

Re: Failed Transmission cooler

Reply #18 – October 11, 2018, 09:02:11 pm

Sorry to here of your problems my friend, hope you can work through them and keep on going. But I do completely understand all the leaves gone on that side of the money tree. JMHO I would have to be looking in used bin for a transmission and cooler.

Re: Failed Transmission cooler

Reply #19 – October 12, 2018, 11:52:01 am

When I read your HOW IT HAPPENED, what comes to mind is that the tranny ATF fluid is too low, which I think you know. Why not add more for now to see if the correct level settles out again.

Does the radiator coolant look like it is mixed with oil, which must separate out on top of coolant after sitting for a while.

Is your tranny cooler separate or part of your radiator.

How did the previous year's repair show its face that made someone think that the tranny cooler failed. This current problem while looking the same, could be different.

In a previous coach, we did bypass the bottom of radiator tranny cooler and add two not-real-large radiator-looking tranny coolers with fan behind. We were able to position the new radiators in the air stream while driving.

Re: Failed Transmission cooler

Reply #20 – October 12, 2018, 12:22:23 pm

While the earlier Allisons w/o lockup will produce a lot more heat, the later coaches with lockup should not need a large ATF to air transmission cooler. Something to think about in the older coaches as this failure could be a game changer.

If the cooler has the internal tubes brazed the choice of coolant is not as critical but soldered tubes may react to some coolant formulations.

Nice if members who may have changed over to ATF to Air coolers would document all the fittings, hoses, cooler(s), the route the hoses took plus how and where the cooler was mounted.

Pierce

Re: Failed Transmission cooler

Reply #21 – October 12, 2018, 05:58:26 pm

OK I admit it. I panicked. Getting close to my move to Ajo and concluded the worst without any diagnostics. Not the transmission cooler. Finally got a chance to get under the coach this afternoon and I found the problem, I also found a bonus problem. One of the hydraulic hoses coming out of the transmission is leaking. Leaks when under way from what I can see. Not leaking enough to stop me from going to Ajo next week. Just a six hundred mile hop from here. Will be able to schedule repairs in Phoenix. Second problem may be more serious. Looks like the right rear wheel seal is also leaking. Gonna have to take a closer look at that tomorrow. Nothing I can personally do about it I'll have to check with a shop in Carlsbad NM. Make an appointment for early next week. Not easy to find a shop I can trust around here.

Roland

Re: Failed Transmission cooler

Reply #22 – October 12, 2018, 06:07:06 pm

Dang. I wanted those tires. You coming through Deming, btw?

Re: Failed Transmission cooler

Reply #23 – October 12, 2018, 06:45:57 pm

Any good truck repair shop can do the wheel seal, not motorhome specific.

Re: Failed Transmission cooler

Reply #24 – October 12, 2018, 06:47:16 pm

BUT (yes, big BUT) the oil may have leaked onto the brake pads. If so you need to do a rear axle brake job.

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