| Stranded near Green Bay [message #366183] |
Mon, 16 August 2021 19:10  |
nchapekis
Messages: 165
Registered: February 2004
Location: Ypsilanti, MI
Karma: 0
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Senior Member |
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Drove about 400 miles from southeast Michigan to the UP yesterday with no issues, until tranny started downshifting to second on flat roads while doing about 55 mph (3:42 final drive). Was able to get it to upshift by releasing accelerator, but then would downshift again when I tried to accelerate. Checked vacuum lines and replaced modulator, but no change. Unfortunately I did not install the new modulator correctly and it started leaking. Tried to reinstall, but too much fluid leaked out and I can no longer move the coach onto a curb to get under it. Can anyone provide assistance or recommend a reliable, honest shop in the area that would be willing to actually work on it? I did locate a tow truck with a wheel lift nearby, just not sure where to have it taken.
If I can get the modulator reinstalled, Manny recommended disconnecting the downshift solenoid, which if the culprit, would allow our vacation to continue.
Thanks in advance.
Nick Chapekis
Ypsilanti, MI
former owner - 78 Kingsley
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| Re: Stranded near Green Bay [message #366185 is a reply to message #366183] |
Tue, 17 August 2021 00:40  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Hi Nick, Here is a second try. I lost the first try and I am typing a shortened second one.
You have what looks to me like a loss or weak vacuum to the modulator. I would be checking or replacing the two vacuum lines going the modulator. Between those two lines is a thin steel tube. That tube can become obstructed with rust or carbon. When that happens you get no or reduced vacuum to the modulator. On mine I had to remove the tube, apply 100 PSI shop air pressure to the modulator end and heat the engine end with acetylene or mapp gas. IN your case (on the road) I would just get enough vacuum hose and make the whole run in new hose. If that works, You can fix it properly later after you return home.
One last thought. Dan Gregg had a similar problem to yours. He said he thought it was the governor. I told him NO but he ignored me. He got a rebuilt governor from Wally and fixed his problem. That ought to tell you that Ken does not always know what he is talking about.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Stranded near Green Bay [message #366187 is a reply to message #366183] |
Tue, 17 August 2021 08:19 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Nick check the surrounding vacuum lines on top of engine. There was a 2” section of hose off a “T” on same circuit that had chaffed through on friends coach. Easy fix.
John Lebetski
Woodstock, IL
77 Eleganza II
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| [GMCnet] Re: Stranded near Green Bay - Conclusion (we hope). [message #366194 is a reply to message #366193] |
Tue, 17 August 2021 19:42 |
sgltrac
Messages: 2797
Registered: April 2011
Karma: 1
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so a vacuum leak?
Sully
Bellevue wa
On Tue, Aug 17, 2021 at 5:39 PM Matt Colie wrote:
> Nick is back on the road, but with really poor cell coverage. It barely
> works for voice.
>
> Nick found a tow driver and transmission guy. That guy looked at and
> understood the problem. I was told he cleaned up the parts and put the
> original
> modulator and spool valve back in, but he did not like the fit of the
> rubber line on the modulator, so they used the piece that came with the new
> modulator and everything seems to be working as it should.
>
> Matt - in his favorite chair with the lights on
> --
> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
> GMCES
> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
> Brakes with Applied Control Arms
> SE Michigan - Near DTW - Twixt A2 and Detroit
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| [GMCnet] Re: Stranded near Green Bay - Conclusion (we hope). [message #366198 is a reply to message #366194] |
Tue, 17 August 2021 23:42 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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People see the rubber hose, but neglect to replace them.
After 45 years, rubber under higher temperature does not survive.
We see power steering and oil lines giving out.
We get calls for them more frequently now.
On Tue, Aug 17, 2021 at 5:58 PM Todd Sullivan wrote:
> so a vacuum leak?
>
> Sully
> Bellevue wa
>
> On Tue, Aug 17, 2021 at 5:39 PM Matt Colie wrote:
>
>> Nick is back on the road, but with really poor cell coverage. It barely
>> works for voice.
>>
>> Nick found a tow driver and transmission guy. That guy looked at and
>> understood the problem. I was told he cleaned up the parts and put the
>> original
>> modulator and spool valve back in, but he did not like the fit of the
>> rubber line on the modulator, so they used the piece that came with the
> new
>> modulator and everything seems to be working as it should.
>>
>> Matt - in his favorite chair with the lights on
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>> GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>> Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| [GMCnet] Re: Stranded near Green Bay - Conclusion (we hope). [message #366200 is a reply to message #366198] |
Wed, 18 August 2021 08:34 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
Karma: 0
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Senior Member |
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Back in the day my brother replaced a transmission, in gravel driveway, in the Minnesota snow only to have the same exact problem.
Did you check the vacuum line? Oh, dang....
________________________________
From: Jim Kanomata
Sent: Tuesday, August 17, 2021 11:42 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Re: Stranded near Green Bay - Conclusion (we hope).
People see the rubber hose, but neglect to replace them.
After 45 years, rubber under higher temperature does not survive.
We see power steering and oil lines giving out.
We get calls for them more frequently now.
On Tue, Aug 17, 2021 at 5:58 PM Todd Sullivan wrote:
> so a vacuum leak?
>
> Sully
> Bellevue wa
>
> On Tue, Aug 17, 2021 at 5:39 PM Matt Colie wrote:
>
>> Nick is back on the road, but with really poor cell coverage. It barely
>> works for voice.
>>
>> Nick found a tow driver and transmission guy. That guy looked at and
>> understood the problem. I was told he cleaned up the parts and put the
>> original
>> modulator and spool valve back in, but he did not like the fit of the
>> rubber line on the modulator, so they used the piece that came with the
> new
>> modulator and everything seems to be working as it should.
>>
>> Matt - in his favorite chair with the lights on
>> --
>> Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL,
>> GMCES
>> Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum
>> Brakes with Applied Control Arms
>> SE Michigan - Near DTW - Twixt A2 and Detroit
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: Stranded near Green Bay [message #366202 is a reply to message #366183] |
Wed, 18 August 2021 09:47 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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Seems old vac hose has 2 fail modes. Hard and brittle like uncooked pasta or soft and mushy like over cooked pasta! Don’t feel bad Nick, I had same issue after my Cinnabar engine install. Hose at modulator was soft and slightly too long so it would collapse or partly kink and restrict. GM vacuum hose was not a simple spec. The architects design specs run about 4 pages as a .pdf. Not sure what materials they used in the 70s, but my friend just reproduced the 80s stuff and had to source the polymer in Japan as not available here. Very specific.
John Lebetski
Woodstock, IL
77 Eleganza II
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