RV Trip Planning Discussions

Go Back   iRV2 Forums > POWER TRAIN GARAGE FORUMS > Allison Transmission Forum
Click Here to Login

Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-30-2018, 10:05 AM   #1
Senior Member
 
mhughes's Avatar
 
Monaco Owners Club
Join Date: Sep 2007
Location: Lancaster, CA
Posts: 547
Groan or grunt noise

After driving through the mountains of Montana and Yellowstone last spring transmission shifting became very erratic. Extremely hard down shifts and flare between gears.

As I approached home, about 800 miles later, shifting got better but far from normal. Decided to change filters. The drained Transynd was far from clear having a slight muddy appearance and an efflorescent sheen. Mileage was 65k. Bought used so I don't know if any prior service had been done.

On the next trip shifting improved greatly after about 800 miles but still an occasional flare and hard shift. Noticed a "groan" or "grunt' between 2nd and 3rd. Fairly pronounced.

Took the coach to the Allison dealer in Coburg who connected a laptop and test drove for about 30 minutes. No codes. Fluid level OK. Did correlate the groan to the torque convert lock up event. Tech suggested a new TCU but had none in stock. Since heading to Salt Lake anyway and they have an Allison distributor there I decided to have another shop take a look.

Salt Lake replaced the TCU, verified fluid levels and test drove another 20 minutes. Tech reported that they didn't notice much change in behavior. Suggested that for another $2k they would pull the control valve assembly and inspect it. As for the groan they said they were not sure of the cause and that torque converter failures were uncommon unless it was a trash truck. Opted to let the issue get worse and headed off to South Dakota.

Groan hasn't changed but shifting gradually got back to normal with only one or two hard shifts and flares.

Any comments or suggestions would be greatly appreciated.

Trans model 3000MH
Mileage now at 67K
__________________

__________________
Mike and Wanda
2008 Safari Cheetah 38PDQ, 350 C7, TRW, F/R X-Bars, F/R Watts, FSD, STP, TST, RF18, SeaLevel II, 800w Renogy PV, 2016 F150 4x4, Blue Ox, AFO, LSL TC
mhughes is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 09-30-2018, 11:33 AM   #2
Senior Member
 
Skip426's Avatar


 
Join Date: Apr 2011
Location: Powell River, B.C.
Posts: 17,708
Any chance the noise could be external of the transmission ?

Lock up; particularly in the lower gears, where RPM and engine torque are at their highest ; puts added load on engine/trans mounts , and you could have the motor mount brackets contacting the frame ; bottoming out the mount ; transferring engine vibration to the whole coach.

If you've had harsh shifting issues for a while , the mounts may have sustained some damage.
__________________

__________________
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.
Skip426 is online now   Reply With Quote
Old 09-30-2018, 11:49 AM   #3
Senior Member
 
mhughes's Avatar
 
Monaco Owners Club
Join Date: Sep 2007
Location: Lancaster, CA
Posts: 547
The noise occurs only during torque converter lockup event between 2nd and 3rd gears. Heavy or light throttle. Never occurs at any other time or gear.

In Coburg the Freightliner/Allison dealer spend more than an hour on the hoist examining the rear suspension and motor mounts. No issues found other than a slight adjustment of ride height.
__________________
Mike and Wanda
2008 Safari Cheetah 38PDQ, 350 C7, TRW, F/R X-Bars, F/R Watts, FSD, STP, TST, RF18, SeaLevel II, 800w Renogy PV, 2016 F150 4x4, Blue Ox, AFO, LSL TC
mhughes is offline   Reply With Quote
Old 10-01-2018, 09:51 AM   #4
Senior Member
 
mhughes's Avatar
 
Monaco Owners Club
Join Date: Sep 2007
Location: Lancaster, CA
Posts: 547
Another odd issue. May or may not be related to current problems. Starter has begun to grind gears. This happens about every 3rd or 4th time I start the engine. Engine usually starts on the second or third try.
__________________
Mike and Wanda
2008 Safari Cheetah 38PDQ, 350 C7, TRW, F/R X-Bars, F/R Watts, FSD, STP, TST, RF18, SeaLevel II, 800w Renogy PV, 2016 F150 4x4, Blue Ox, AFO, LSL TC
mhughes is offline   Reply With Quote
Reply

Tags
noise



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wind noise and crackle noise Bowl300 Newmar Owner's Forum 6 01-05-2017 07:18 PM
Start Your Day with a Groan pumper9x9 RV'ing Humor & Crazy but True Stories 2 08-14-2016 05:38 AM
Transmission Shudder/Groan MartinP Allison Transmission Forum 14 07-02-2013 07:41 PM
Brake-pedal groan... Richard 34A Winnebago Industries Owner's Forum 9 04-02-2008 05:58 PM

» Featured Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 07:48 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2019, vBulletin Solutions, Inc.