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OJ Avery

allison trans cooler

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I have a 13 GU with a 3000/4000 series ( I think ) Allison in it.  Serial # 6610336363, cooling system is full of trans fluid so my assumption is the cooler is bad. its an internal one on the back of the trans. I'm not finding much literature on it so any help would be greatly appreciated. Is it as straight forward as the parts diagram shows? Do's and don'ts ?

Thanks!!

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Hello??..is this thing on lol?? another question, I am having no luck finding any literature on this thing. I pulled the cooler and put it in the parts washer tank and put about 30# of air to it , no leaks. what is the typical pressure running through the cooler??

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We have no dealings with anything Allison at our shop even though we sell quite at few new ones with Allison trans in them. We send them to our authorized Allison dealer 

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you won't get too many guys on here experienced on Allison trans, as said it is mostly a dealer thing....  I've worked on the B400/500 but in a bus application, not too different to what you have... we have laptops and trans dyno to use so I am not going to point out any bush repairs as failure is costly with an Allison... and they don't work for too long with antifreeze in the clutchplates so hope you got there early and nothing leaked back into the trans.

buses have a remote cooler because the retarder mounts at the rear but similar in application to what you have, an oil core inside a coolant can..!!!! I assume yours is an oblong unit under the output flange??. it is probably the source of your problem, but we don't see too many of that fault just blocked up with debris or cracks causing coolant drips...we remove them on a semi-regular basis for reverse flushing and pressure testing

if the oil core has a leak we scrap the whole unit, we just fix the can.

pressure inside the trans is up to 300psi so we use Transynd not ATF

literature would be generic and there are manuals on ebay and how to videos on youtube (try 'Allison 4000')

you have to be an approved Allison shop to get the on-line manual and they are VERY specific to serial number, especially for parts pages, I made my own up for all our variants but never printed the cooler section, or pto..!!.

we pressurise the coolant side to 100psi immersed in a water tank, the reverse flush is done on a machine with a air/hyd pump and pushes about 150psi through them....not sure how you would hook up the hydraulic side on your unit

if you get totally stuck I get back to my old shop occasionally, books are there, but I think you need info quicker

hope this helped

BC Mack

 

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Thanks BC Mack and Mack Pro. I contemplated sending the cooler out for pressure testing because even though I didn't know what the pressure at the cooler typically was, I knew I wouldn't be able to simulate it. But I went with a new cooler. Second try of course. I ordered everything before I took it apart, I ordered a 7 plate and this has a 17 plate cooler. Yes the cooler is below the output shaft. We've started servicing the Allison's here, and typically anything more than that we send to a Allison dealer, but I figured this wasn't a complicated process so we decided to keep the truck here. We have a couple hundred 13-15 Mack GU with the Allison and we've experienced very few problems.  Thanks again , I can always count on both of you to help out.

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I'm having troubles locating Allison service bulletins, specifically Allison sil 18-TR-98

Any help would be appreciated

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On ‎7‎/‎25‎/‎2018 at 5:15 AM, OJ Avery said:

I'm having troubles locating Allison service bulletins, specifically Allison sil 18-TR-98

Any help would be appreciated

I'm on vacation right now, will try to dig it out when I get back, if we have access to that one... hope you're in no hurry

BC Mack

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to get oil in the cooling system you are getting trans pressure leak.you need to know what the trans pressure is.

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On ‎7‎/‎25‎/‎2018 at 5:15 AM, OJ Avery said:

I'm having troubles locating Allison service bulletins, specifically Allison sil 18-TR-98

Any help would be appreciated

Sooooo, I get back to the tranny shop and see #1 guy there.... he searches the database and nothing comes up.... so we did a word search of all our on-line manuals and find it as a reference for one of the assembly sections... but no 'go to' button..... the text refers to water or glycol check

as I mentioned before, water or glycol is kryptonite to these trans as the bonding glue holding the friction surface to its disc is water based and as the debonding occurs the friction surface comes apart... end of tranny

he's going to dig deeper and get back to me if he can find info, but his comments were to flush the trans, flush again, filters, filters, run with synthetic and do lots of samples... make sure there is NO water or glycol coming back on the oil reports.

not sure what your change frequency but we used ATF changing at 24,000km, now we have gone to Transynd at 72,000km changes, samples at 24k.... with retarders we were boiling the oil on downhill runs, synthetic took the heat with no issues... now the coolant overheats and warps the engine block..!!! can't win with hills...

BC Mack

 

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Posted (edited)

Our newer Allison 4000 and 5000 series on Bus application (2015 and up) have the stack plate type trans coolers under the drive shaft. Plate type coolers always seem to have a higher failure rate. The old standard pressure testing both sides may not show signs of leakage. Your test won't produce heat which is a large cause of plate type cooler failure. It's the only spot your coolant and auto trans fluid mix. Change it and flush both systems real good. 

Edited by bbigrig
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So everything seemed to go well until last week. I heard from the residency mechanic that when its got a full load it shifts hard 1-2 and there's a code for a solenoid. Haven't seen the truck yet, will keep you updated. Thanks for all your efforts, I appreciate you all!!

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12 hours ago, OJ Avery said:

So everything seemed to go well until last week. I heard from the residency mechanic that when its got a full load it shifts hard 1-2 and there's a code for a solenoid. Haven't seen the truck yet, will keep you updated. Thanks for all your efforts, I appreciate you all!!

don't panic yet..!!!!!

depending on mileage (ours are toast at 350km of city work) it could be simply a piece of debris stuck in the valve body.... N-D-N-R a few times on the keypad when at idle may be all it needs.... it's one of the most common complaints we get.... check the code and the manual will run you through the problem, pressure checks etc, if you have to drop the pan that will expose the valve body and solenoids, if you have to remove any wiring be careful with the clips on the solenoids as they get brittle with the heat and the wiring can also 'snap'...

BC Mack

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