Skip to main content ↑ ↓
Topic: Transmission problem? (Read 1264 times) previous topic - next topic

Transmission problem?

We started hearing an odd sound that is mid ranged the goes high low, high low. I have heard something like it, but it was confined to the rear of the coach driver's side, about where our def fill is.
The sound started low this morning, all gauges were normal, it would come and go.At first we thought it might be the tires making it, due to the road. Then it became steady. We stopped once and got a engine check light. My DH, checked as much as he could and reset the fuel cap, light went out. We stopped a second time and could really hear this oo-woo sound as we started to pull out. Then as the motor reved more, it lessened, but was still there under the other noises. Will check transmission fluid once engine cools and the thunderstorm quits. Any ideas?
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723

Re: Transmission problem?

Reply #1 –
Is the "check engine light" something new? What were your coolant and tranny temps right before the light came on? Could be a hydraulic pump noise or PS pump noise. Check trans fluid level, color of the fluid and then smell it. How about any fault codes for the engine or transmission?

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Transmission problem?

Reply #2 –
Hard to diagnose over the web, but here are some questions that might help you/a shop:

Is it road speed dependent? (in other words, does the sound change directly with how fast you're going)?

Is it engine RPM dependent (does the sound change directly with the RPMs - thus changing as you move through gears but being similar between gears as you accelerate in that gear's "band"?

Does it happen at idle/in neutral with the parking brake on?  If so, what happens as you increase the RPMs of the engine (keep your foot on the brake)?  If it happens at idle, can someone go outside and listen (with the engine bay door open) and possible narrow down where it's coming from while the other person runs the RPMs up and down?

Is it primarily on one side of the rear or is it hard to tell?

Once warmed up, use the Allison keypad to check transmission fluid level (manual in the Media section here).

If you're handy, and have the right wrench, check the fluid level in the differential.



That said, as I was typing this one thing that came to mind is the hydraulic fans/PTO.  This is a known issue with the 2007-2010 Cummins engine'd coaches, pre-DEF - mostly the Phenix, but I recall some discussion of Nimbus sort of being included, although no known failures on a Nimbus  documented the last time this was discussed.  Yours is a 2012 Nimbus with DEF so might not be suspect but worth investigating through FT. 

Am driving my last Foretravel !!!!!

Break down on I-10 (fan pump failure)

Defect notification - Who has responsibility to notify and repair?
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Transmission problem?

Reply #3 –
Most diesels will have a quite noticable resonant frequency depending on the rpm and load.
Old Phart Phred, EIEIO
89 GV ored 36' #3405 300 hp cat 3208 ATAAC side radiator, mountain tamer exhaust brake

Re: Transmission problem?

Reply #4 –
Also check rear axle fluid level.
Dan - Full timing since 2009
2003 U320 40' Tag 2 slide

Re: Transmission problem?

Reply #5 –
Thanks for the help, we will explore several of these leads. Some in the morning, before we start calling.
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723

Re: Transmission problem?

Reply #6 –
Quote from: AC7880 –
Also check rear axle fluid level.

Especially if the noise only occurs when in motion and "service third member" was part of the service that resulted in low engine oil a couple of months ago Wondering who is at FT in Nacogdoches
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Transmission problem?

Reply #7 –
Do yourself a favor and have the transmission looked at by Allison and the engine with Cummins. Remember, FOT has no experienced or serviced qualified personal to work on transmissions, engines, or rear ends. As an owner of a 2007 Nimbus, we have stayed clear of FOT in these aspects. Yes, they can change the oil if you trust them. I did once and found the oil filter hanging on by a few threads. Enough said.
Bob
Bob & Kathy
2007 Nimbus
Full Timers
Retired Charter Bus Owner/Operator

Re: Transmission problem?

Reply #8 –
Just an update: retarder had been turned off. Axel level good. Oo-woo noise still notice. But when we pulled in to park, the camp host was talking with DH and said that it was the engine. He had heard the same noise on his parents RV and they ended up at Cummins for a bearing replacement.  So once we depart HWH, we will locate a Cummins place to get it checked out. And probably Allison too.
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723

Re: Transmission problem?

Reply #9 –
Update: 3, stopped at Cummins and they diagnosed a hydraulic driven fan that cools the engine. But said it wasn't a Cummins part.  A call to FT ended up with Mr. Triana calling back. He gave us info to go to Omaha Cummins, who work on RV's and that the fan is just stuck in a fast position. We will be able to make it, but our mileage is going to be in the very low numbers.
Again thanks to all of you who helped, it is great to have support.
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723

Re: Transmission problem?

Reply #10 –
Could use up 60hp in the fast position. Glad you got it. I suspected it might be hyd pump/motor noise. Cheap and easy fix.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Transmission problem?

Reply #11 –
Quote from: pugmom –
Update: 3, stopped at Cummins and they diagnosed a hydraulic driven fan that cools the engine.

Thanks for posting the diagnosis  ^.^d  Let us know how the repair goes.
Learn every day, but especially from the experiences of others. It's cheaper!  - John C. Bogle

2000 U320 36' non-slide / WildEBeest Rescue
2003 U320

Re: Transmission problem?

Reply #12 –
Quote from: pugmom –
Update: 3, stopped at Cummins and they diagnosed a hydraulic driven fan that cools the engine. But said it wasn't a Cummins part.  A call to FT ended up with Mr. Triana calling back. He gave us info to go to Omaha Cummins, who work on RV's and that the fan is just stuck in a fast position. We will be able to make it, but our mileage is going to be in the very low numbers.
Again thanks to all of you who helped, it is great to have support.

I cannot right now think of the name for the company that makes the controller for the hydraulic fans but there will a unit by the engine. Normally, when the coach is idling the fans should be off or not turning. Only when you are driving the coach, the fans start on low and then move automatically to high when more cooling is needed. Stop in traffic and the once stopped the fans will stop too. Now, if the fans like on my coach were to be running when stopped, then you will hear whet sounds like bearings going bad in the fan area. This is caused by cavitation due to low hydraulic oil pressure in the lines since the fans in the first place should not be running. Finally, when they check out the unit and find that the fans do work on low and high speed, then the problem goes back to Foretravel to reprogram the computer to operate the fans normally. We had this issue and dealt with it over three years until I was able to convince FOT to check the programing and low and behold, the programing was never done. Imagine that. This cooling system is much different than in coaches dating back in time.
Bob
Bob & Kathy
2007 Nimbus
Full Timers
Retired Charter Bus Owner/Operator
 

Re: Transmission problem?

Reply #13 –
Thanks Bob,
Good info, sounds exactly like what our fan is doing. We did not notice any problems with the fan, until our problem with the nox sensor this spring. I am now wondering if perchance the programming got messed up when Cummins of North Ft Worth worked on the engine. We are not happy with their work, anyways.
Will have the Omaha Cummins do a check and if it is programming, then will make an appointment with FOT since we will be down that way by late October.
Just wish that the side effect of this wasn't the coach sucking fuel, we have dropped from an average of 7 mpg to between 4-5 mpg. At $2.79 it makes a difference. :o
Lynn and Linda Day and Harry the pug
RIP: Tank 01-2008 to 03-2020
2012 Nimbus 42' build 6555
ISX12-500hp
2015 Jeep Grand Cherokee
MC# 17723