| Transmission downshifting [message #290101] |
Sun, 08 November 2015 07:57  |
tgeiger
Messages: 518
Registered: February 2006
Location: kansas city
Karma: -1
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Senior Member |
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I noticed coming back from camping last weekend my motorhome would downshift from 3rd to 2nd doing 50 mph and it wouldn't shift up to 3rd until I manually went down to 2nd and then back up to D and then it would kick up to 3rd. I've check the transmission fluid and it seems to be good level . I have noticed a hissing noise under the dash when I let off the brake. I have had trouble with mice in the coach and am wondering if those little s$&ts have chewed on something that has caused a vacuum issue? Anyone experience a hissing noise related to the brake peddle coming back up after use. It does stop hissing when peddle comes back up after I pressed on it.
Tom Geiger
76 Eleganza II
KCMO
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| Re: [GMCnet] Transmission downshifting [message #290102 is a reply to message #290101] |
Sun, 08 November 2015 08:40  |
Bruce Hart
Messages: 1500
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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Senior Member |
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Tom,
Like gene states"Go Here"
http://gmcws.org/blog/
Than "Go Here"
http://www.bdub.net/
"Here"
http://www.bdub.net/GMCLinks.html
Scroll down and open Manuals
Scroll down to bottom of page and open:
THM425 Trouble Shooting 1973
Go to page 11 in manual for a flow chart.
On Sun, Nov 8, 2015 at 6:57 AM, tom geiger wrote:
> I noticed coming back from camping last weekend my motorhome would
> downshift from 3rd to 2nd doing 50 mph and it wouldn't shift up to 3rd
> until I
> manually went down to 2nd and then back up to D and then it would kick up
> to 3rd. I've check the transmission fluid and it seems to be good level . I
> have noticed a hissing noise under the dash when I let off the brake. I
> have had trouble with mice in the coach and am wondering if those little
> s$&ts
> have chewed on something that has caused a vacuum issue? Anyone experience
> a hissing noise related to the brake peddle coming back up after use. It
> does stop hissing when peddle comes back up after I pressed on it.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
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Unsubscribe or Change List Options:
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: [GMCnet] Transmission downshifting [message #290107 is a reply to message #290102] |
Sun, 08 November 2015 12:41 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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The drop in vacuum through the cruse control , if located close to the
transmission modulator connection at the intake can cause that problem.
If nothing else look at the connection at the intake manifold and see that
it is a dedicate one, not sharing with another.
On Sun, Nov 8, 2015 at 6:40 AM, Bruce Hart wrote:
> Tom,
>
> Like gene states"Go Here"
> http://gmcws.org/blog/
>
> Than "Go Here"
> http://www.bdub.net/
>
> "Here"
> http://www.bdub.net/GMCLinks.html
>
> Scroll down and open Manuals
>
> Scroll down to bottom of page and open:
> THM425 Trouble Shooting 1973
>
> Go to page 11 in manual for a flow chart.
>
>
>
>
>
>
> On Sun, Nov 8, 2015 at 6:57 AM, tom geiger wrote:
>
>> I noticed coming back from camping last weekend my motorhome would
>> downshift from 3rd to 2nd doing 50 mph and it wouldn't shift up to 3rd
>> until I
>> manually went down to 2nd and then back up to D and then it would kick up
>> to 3rd. I've check the transmission fluid and it seems to be good level
> . I
>> have noticed a hissing noise under the dash when I let off the brake. I
>> have had trouble with mice in the coach and am wondering if those little
>> s$&ts
>> have chewed on something that has caused a vacuum issue? Anyone
> experience
>> a hissing noise related to the brake peddle coming back up after use. It
>> does stop hissing when peddle comes back up after I pressed on it.
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>
>
>
> --
> Bruce Hart
> 1976 Palm Beach
> Milliken, Co
> GMC=Got More Class
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Transmission downshifting [message #290109 is a reply to message #290101] |
Sun, 08 November 2015 14:16 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Mice could have chewed kick down switch wires and shorted them. On gas pedal upper fulcrum. Also to adjust, slide by hand to more sensitive, then depress the pedal once all the way and it self sets. But wires can't be chewed and shorted.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Transmission downshifting [message #290166 is a reply to message #290101] |
Mon, 09 November 2015 16:46 |
tgeiger
Messages: 518
Registered: February 2006
Location: kansas city
Karma: -1
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Senior Member |
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Ok guys, will take a look at these things. Tried dryer sheets, mice made nest out of them...then moth balls around the tires...I think they just used them as a step stool to get up on the tires...now its going to be peppermint oil sprayed through the coach...hey at least it smells like Christmas inside it. Thanks for the good advice, I'll take a look at those items and see if I see anything from those little mongrels.
Tom Geiger
76 Eleganza II
KCMO
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| Re: Transmission downshifting [message #290186 is a reply to message #290166] |
Tue, 10 November 2015 12:59 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Senior Member |
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tgeiger wrote on Mon, 09 November 2015 15:46Ok guys, will take a look at these things. Tried dryer sheets, mice made nest out of them...then moth balls around the tires...I think they just used them as a step stool to get up on the tires...now its going to be peppermint oil sprayed through the coach...hey at least it smells like Christmas inside it. Thanks for the good advice, I'll take a look at those items and see if I see anything from those little mongrels.
I don't have mouse problems, but if they act anything like Pack Rats, the only thing I have found that keeps them away is light. A couple of light ropes under, or around the coach does the trick for the rats or one of these:
http://www.rid-a-rat.com/
I have a Rid-a-Rat under the hatch of the coach and under the hood of anything else I park outside and I can testify that they work on nocturnal rodents.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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