2001 Patriot Thunder Beaver C-12 trans problem

[Loren Harris]

Hi, does anyone know why this happened: I was cruising until I started going down a small hill with my Beaver RV and I used the jake brake retarter which always has worked perfectly in the past and the transmission automatically shifted down to the "5" range and the trans stuck in that range even after getting back on flat freeway. Then I noticed the trans temperature was going up so I stopped for an hour and then started it up and everything worked fine for the rest of my 100 and some miles. I don't know if it was the retarder or the trans giving me a problem. I was towing my Saturn at the time. Anyone has any information or maybe the same thing happened to them please let me know before I go out again. Hate to take it to a shop but might have to do it. I have Good Sam extended warranty and maybe that would cover the problem. Depends on the price and my $500 deductible. Loren Harris. 661-943-1739. 2001 Beaver 425 C-12 Patriot Thunder.

[Edward Buker]

Loren,

I am not sure about the temperature and how hot the transmission actually got. When you use the jake brake (which is not a retarder, a retarder is another braking device that resides within the transmission that we do not have) you should not see much of a temperature rise unless the engine for some reason has its temperature rise. The transmission is cooled by the engine coolant so it will nearly mimic the engine coolant temperature.  I have noticed that when you engage the jake brake and it invokes a downshift you will remain in that gear until the throttle pedal is used again even though the jake has been turned off. Not sure if that was what you were observing, but if it was that is normal.

Later Ed

[Ron Johnson]

I need to go at least 63 mph before my PT will shift from 5th to 6th .. until then it does feel 'stuck' in 5th.

[Gerald Farris]

Loren,
I will need more information before I can say if you have a problem or not. Like what speed were you driving and what was the throttle position when the coach would not shift out of 5th gear? Also what where the driving conditions when the transmission began to heat-up, and what temperature did it reach?

It will probably be nonproductive to take the coach to a shop unless you can duplicate the problem. However, it may be a good idea to have the local Allison shop run a fluid analysis if you are not certain about the fluid condition.    

Gerald

[Neal E Weinmann]

Has the exhaust brake mechanism been properly maintained/lubricated so that it operates correctly?

[Loren Harris]

Thanks for all of your answers. I did have low coolant in the engine which was about 4 of the large liter Pepsi type bottles low. I never had this problem before but in my first report I never mentioned the engine coolant being low so maybe that was the problem since it works fine now. The jake brake works fine and everything else. It just sorta scared me since this has never happened in 60K miles. I had it service last year completely by Caterpillar so thought everything was fine then. I will take your advice and simulate the problem since I didn't do it after that. I only went to where I was going as lightly as possible and all worked fine. I will address this again if it happens or if I get any answers to what I did wrong or whatever happened. But now that I know the trans is affected by engine temp I am sure it was the engine coolant being low if anyone would like to comment on that. Thanks, Loren Harris.

[Joel Ashley]

If your coolant got below the minimum level sensor in the expansion tank, it could trigger your Check Engine light on your instrument panel and the engine into limp mode to protect itself.  Your angle on the small hill may have been just enough to affect the tank sensor.  You should be aware that an unreprogrammed tranny will not shift to 6th gear until your road speed is around 63 mph, and will drop back to 5th if your speed subsequently falls to around 58.  But it doesn't really sound like you actually went into limp mode... you would have seen a more radical power change, and you made no mention of a Check Engine lamp.

Joel

[Edward Buker]

Loren,

You never mentioned what the temp of the transmission was and if you noticed what the engine temp was. Coolant flow through the components can be affected if the coolant is too low and you were down a gallon or so. I would check the coolant level and watch it closely for awhile to be sure you do not have a leak somewhere. If during your service the coolant was changed it could be it was never completely filled. Sometimes there is air in the system and after any coolant change some addition needs to be added after the system is run and cools.

If you now know that the coolant system is full and then you really do see an abnormal temperature excursion you should bring it in and have the problem sorted out. Write down the normal engine and transmission temps and what each of those read during any temp excursion that concerns you to share with the shop.

Later Ed