My Allison transmission is acting up

Topic: My Allison transmission is acting up (Read 2779 times) previous topic - next topic

Re: My Allison transmission is acting up

Reply #25 – June 13, 2014, 10:02:37 am

Chuck, the dealer here said that they had to remove the tranny, they are certain the the solinoids will need attentions as well sat the plates. The engine coolant will also have to be flushed etc. However they won't start the process unless they have all the parts. Kinda don't blame them as the coach will then be occupying a bay and they are a busy outfit. That is the reason for my driving sans accumulator until I can install a transmission cooler. Would not let the temps go over two hundred, but I wonder if it feasible.

Roland

Re: My Allison transmission is acting up

Reply #26 – June 13, 2014, 10:08:39 am

Chuck,

Again, heat is the enemy here and torque converter slippage at idle and first gear will create a lot of heat. Roland has lockup half of second and all of third and fourth so the heat generated will be much less but still there. I watch my trans temp like a hawk.

No, you can't drive without a tranny cooler and expect the Allison to live.

Pierce

Re: My Allison transmission is acting up

Reply #27 – June 13, 2014, 10:18:21 am

Roland,

Trying to read between the lines here. Are you thinking of putting the lines together and perhaps driving to another shop? Or, do you want to get it fixed leaving the radiator alone with the AT lines directly connected to get somewhere to then install a separate cooler? With ATF in the coolant and probably vice versa, both issues should be addressed before any drive. Then you could drive the vehicle to another shop for cooler installation but not to another city in summer heat.

Pierce

Re: My Allison transmission is acting up

Reply #28 – June 13, 2014, 10:28:32 am

Was thinking of getting it fixed, bypassing the accumulator, and driving it to where I or someone can install a transmission cooler. Not sure there is a shop in the immediate area that would install a cooler.

Roland

Re: My Allison transmission is acting up

Reply #29 – June 13, 2014, 10:40:22 am

OK, then contact someone like B&M to see how feasible a separate cooler would be. They have the experience to tell you how far and under what conditions you can drive the coach without a cooler installed.

Pierce

Re: My Allison transmission is acting up

Reply #30 – June 13, 2014, 01:38:36 pm

Just got back from the shop. They could not find the original part or a substitute part for the accumulator. They did however search for a separate transmission cooler and have come up with a cooler that will work with the Allison. Got a quote for parts

5 coach bucks, waiting for the labor quote. Guess when I went to the shop yesterday they were extremely busy and kinda short with me so I got the impression that they did not want to modify. They will not get the parts until the end of next week sometime, don't think I can stay in a Motel 6 that long and maintain my sanity. Going to continue our journey in the toad and come back when the coach is ready.

Roland

Re: My Allison transmission is acting up

Reply #31 – June 13, 2014, 01:40:09 pm

Have you priced a genuine Allison reman transmission?

Re: My Allison transmission is acting up

Reply #32 – June 13, 2014, 01:42:32 pm

Brett, haven't priced the reman transmission, but a big part of the parts cost was for the transmission cooler and associated hydraulic hoses. Will ask though when they call as that might make a difference in total cost.

Roland

Re: My Allison transmission is acting up

Reply #33 – June 13, 2014, 03:03:55 pm

Has the fluid been drained from the transmission and checked for contamination? I'd sure do this before tearing into it. It could be that it is not contaminated, or that it's an insignificant amount, could be the filters caught it. After all, sounds like your ATF has been blowing into the radiator, and level dropping in the trans. Other than a hard shift, wasn't the trans working? I'd sure do some checking before committing to a trans tear down or replacement.

What or where is this accumulator? Maybe I'm wrong but the only one I'm aware of is on the retarder, a hydraulic unit.

Re: My Allison transmission is acting up

Reply #34 – June 13, 2014, 03:22:54 pm

Sounds like this is getting out of hand for a transmission cooler leak. I'm thinking more like Chuck. Have you seen any coolant in the transmission fluid?

Pierce

Re: My Allison transmission is acting up

Reply #35 – June 13, 2014, 03:27:20 pm

Roland, I have been reading your dilemma. Your coach is different than ours, so the terminology is not clear to me.

We have a transmission retarder which has an Allison accumulator that activates the retarder and it is not related to cooling. We also have a transmission cooler that flows transmission fluid from and to transmission, and to remove heat from transmission fluid, the cooler also has engine coolant flowing in and out, but the two fluids are not in contact with each other. I can see that if the cooler insides deteriorate they could allow engine coolant to flow to transmission and vice versa.

Do you have a retarder and if not, is the 'accumulator' your transmission cooler? And is the Cummins shop installing an air cooled transmission cooler.or another type of engine coolant - transmission fluid cooler?

I have heard that our type of accumulator and our transmission cooler may no longer be available, so we all could face similar issues.

Good luck.

Re: My Allison transmission is acting up

Reply #36 – June 13, 2014, 03:45:42 pm

Chuck makes sense on not having coolant in the transmission, because the transmission fluid pressures are probably much higher than the coolant, which tops out about 15 PSI, limited by radiator cap setting.

Re: My Allison transmission is acting up

Reply #37 – June 13, 2014, 04:08:21 pm

1. The transmission fluid is contaminated. The shop took fluid out of the tranny and it was colored like my antifreeze. So although a lot of tranny fluid wound up in the antifreeze for the engine there was some "cross contamination". Shop says only way to assess what needs to be done is to look inside. They will only replace what needs to be replaced. They do not feel that merely flushing the tranny is the appropriate approach although they did give me that option.

1a. The tranny was shifting OK but was a real slam shifting down to first gear. I had to add three quarts of fluid before it was visible on the stick without the engine running. With the engine running it "disappeared".

2. I called the parts department In NAC and described my issue. They said it sounded like a bad transmission cooler. The part number they gave me 29506669 is described as an accumulator. The shop here says that us an incorrect part number as it mounts on the side of the radiator whereas my defunct piece is on the bottom. The Allison shop cannot find a new cooler for my tranny, it is no longer manufactured and there is no replacement therefore they will install a separate tranny cooler.

3. I do not have a retarder so perhaps "accumulator" is not an appropriate description of the bad module. The bad module is my tranny cooler.

I hope this clears things up a bit.

Roland

Re: My Allison transmission is acting up

Reply #38 – June 13, 2014, 04:21:08 pm

Roland..

So what option are you taking..

pull the transmission for an inspection or flush.??

Hans

Re: My Allison transmission is acting up

Reply #39 – June 13, 2014, 04:32:38 pm

Actually, a leak between transmission and coolant OFTEN does the following:

When driving, ATF is generally under more pressure so ATF gets into the coolant.

With engine off, ATF pressure drops to zero and the pressure cap on the coolant system gives the cooling system higher pressure, so coolant flows into the transmission.

Re: My Allison transmission is acting up

Reply #40 – June 13, 2014, 05:12:50 pm

Quote from: sfbmw – June 13, 2014, 04:21:08 pm

Roland..

So what option are you taking.. pull the transmission for an inspection or flush.??

Hans

I am taking the remove transmission and fix whatever needs to be done. They told me they would only replace and charge me for what needed to be replace. I inquired what a reman mission would cost, they found one for 8coach bucks but no core credit. Reman mission more than total labor cost. So I Opted to repair mine. I am happy that they will be installing a separate transmission cooler, no more issues with cross contamination. I contemplated driving with the transmission cooler bypassed and installing a xmission coole myself but decided I am better off letting them take care of it.

Roland

Re: My Allison transmission is acting up

Reply #41 – June 13, 2014, 05:20:16 pm

As an aside to this thread, I called Joe Triana today he returned my call. Agrees that I stand a good chance of overheating the xmission driving without a cooler. Re-enforces my belief that we have good support in NAC for a 20+ year old coach. How many SOB can make that claim? With all the issues I have had I would still would not have anything but a Foretravel.

Roland

Re: My Allison transmission is acting up

Reply #42 – June 13, 2014, 06:07:43 pm

Roland, Thanks for sharing the details with us and Brett makes it clear that coolant is in the transmission and it sounds like internal exam is the best long term route. Good luck.

Re: My Allison transmission is acting up

Reply #43 – June 13, 2014, 06:21:58 pm

Perhaps I will state what I will do differently: I absolutely would check with the closest Allison dealer for the price on an Allison factory reman. Then have the dealer where the coach is located install and THROUGHLY flush the lines.

I still don't know what accumulator you are talking about, but either James Triana or Allison could certainly address that.

And, I would have the radiator repaired or replaced. External transmission oil coolers can easily OVER-cool in cold temperatures. You don't want ATF really hot OR really cold.

And, for those who want to add an external oil cooler, Hayden and many others make them in enough different sizes to accommodate your transmission. I would install it BEFORE the in-radiator cooler, That way, if in very cold temperatures, at least it would have a chance to warm slightly. A better solution IMO would be to have ball valves that would allow you to send ATF through the extra cooler in the summer and straight to the radiator cooler in winter.

Brett

Re: My Allison transmission is acting up

Reply #44 – June 14, 2014, 08:08:14 am

Quote from: wolfe10 – June 13, 2014, 06:21:58 pm

Perhaps I will state what I will do differently: I absolutely would check with the closest Allison dealer for the price on an Allison factory reman.

Brett

I am at an Allison dealer. They searched for a replacement cooler (what I was calling the accumulator, my error) without any success. They did price out a reman Allison at $8'000 with no core credit. Decided to fix mine instead, my choice. The separate cooler will be mounted in the engine compartment and that may mitigate the excess cooling. In any case this was the Allison dealer's recommendation and I went with it.

Roland

Re: My Allison transmission is acting up

Reply #45 – June 17, 2014, 08:54:10 am

Roland,

Replacing my lift pump yesterday, I looked down and thought "hmmmm, what is that thing." About 8" in diameter, hydraulic lines running in, coolant line connecting it to radiator, and realized it's an external closed loop transmission cooler, installed in radiator circuit. So, it appears to me this is most likely the accumulator referred to in your posts. Just a thought, if you can't find an exact replacement for that piece, it's a pretty standard item in the marine industry, commonly called a "gear cooler", gear being the transmission. Items like this are spec'd by horspower, line size, corrosion resistance, and connection configuration. Hydraulic fluid flows through a loop inside, cooling water flows around loop, heat is transferred. Most are cupro nickel as the cooling is by seawater.

While I realize you've already got the solution figured out for your situation, I owe you an apology for questioning the existence of the accumulator. If possible, don't junk this part. It may well be repairable, I've got a guy who does these sort of things.

Re: My Allison transmission is acting up

Reply #46 – June 17, 2014, 09:11:27 am

Chuck, if I understood correctly the shop is not going to remove the cooler, accumulator, or whatever that thing is called, they are just going to cap it off. Now in the event that they do remove it I will make sure that I keep the thing and see if it can be repaired.

Roland

Re: My Allison transmission is acting up

Reply #47 – June 17, 2014, 09:33:34 am

I believe FT replaced one when I was in Nac this jan on a friends coach it was 3,000 bucks.

Re: My Allison transmission is acting up

Reply #48 – June 17, 2014, 09:54:25 am

John, when I called NAC they did not have any for my coach. Told me they had been discontinued by Allison. The Allison dealer in Hagerstown could not find any replacement parts either. Don't believe they searched any marine industry applications though, but didn't know about that back then. I did find a couple on e-Bay but the bidding was closed and the parts were no longer available. Unfortunately, my contribution to the Hagerstown economy is going to be a bit more than three coach bucks.

Roland

Re: My Allison transmission is acting up

Reply #49 – June 17, 2014, 10:37:02 am

I will check and see but I think it was a transmission cooler. They thought they would have to retrofit it but it fit in.

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