Transmission problems

G

gene

New member
Sep 29, 1999
2,215
0
0
If your spedo is reading 0, this might be the problem

http://www.california.com/~eagle/transmission.html

gene

>Hi Guys,
> I just got back from a work trip...used the GMC to
>camp in while we did a couple roof jobs in Baldwin Mi.
> anyway, got back to Lansing after highway driving for
>over 150 miles and when it downshifted into low at a
>red light I couldnt get it to shift into third...the
>engine was revving pretty high and after a few minutes
>it did shift into high gear....I did try manual shifting
>which didn't help. Anyone have an idea???
>We are supposed to be going to Coldwater this weekend...
>Rob Teed 74 Painted Desert
>
>_____NetZero Free Internet Access and Email______
> http://www.netzero.net/download/index.html
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
Hi Guys,
I just got back from a work trip...used the GMC to
camp in while we did a couple roof jobs in Baldwin Mi.
anyway, got back to Lansing after highway driving for
over 150 miles and when it downshifted into low at a
red light I couldnt get it to shift into third...the
engine was revving pretty high and after a few minutes
it did shift into high gear....I did try manual shifting
which didn't help. Anyone have an idea???
We are supposed to be going to Coldwater this weekend...
Rob Teed 74 Painted Desert

_____NetZero Free Internet Access and Email______
http://www.netzero.net/download/index.html
 
No,,the speedo seems to work OK...
Rob Teed

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of gene
> Sent: Friday, July 14, 2000 1:06 AM
> To: gmcmotorhome
> Subject: Re:GMC: Transmission problems
>
>
> If your spedo is reading 0, this might be the problem
>
> http://www.california.com/~eagle/transmission.html
>
> gene
>

> >Hi Guys,
> > I just got back from a work trip...used the GMC to
> >camp in while we did a couple roof jobs in Baldwin Mi.
> > anyway, got back to Lansing after highway driving for
> >over 150 miles and when it downshifted into low at a
> >red light I couldnt get it to shift into third...the
> >engine was revving pretty high and after a few minutes
> >it did shift into high gear....I did try manual shifting
> >which didn't help. Anyone have an idea???
> >We are supposed to be going to Coldwater this weekend...
> >Rob Teed 74 Painted Desert
> >
> >_____NetZero Free Internet Access and Email______
> > http://www.netzero.net/download/index.html
> >
> Genef -- 77PB/ore/ca
> GMC MOTORHOME INFORMATION
> mr.erf
> http://www.california.com/~eagle/
>

____________NetZero Free Internet Access and Email_________
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Rob,

That has been our first symptom of clutches slipping. The clutch
material reportedly obstructs the filter enough to lower the control
pressure. We have also had the particles gum up the governor enough to
make it sluggish to upshift, starting out as a reluctance to shift to
third, and later, the same reluctance to shift into second.

We could see gunk in the governor the last time this happened. Cleaning
the governor and replacing the filter kept it alive for another thousand
miles. We could see a fine black material on a white paper towel after
checking transmission fluid level - couldn't see it on blue towel -
first noticed about a thousand miles before the first balky shifting.

Another possibility would be the modulator, or a leak in the vacuum line
to the modulator.

If it's clutches, running it can be expensive. After you run out of
friction material, it starts chewing up the steel skags, and that eats
up just about everything in the transmission.

Not claiming any real knowledge of these transmissions, just my personal
experience.

Walt Taylor
Austin, TX
'75 Eleganza

>
> Hi Guys,
> I just got back from a work trip...used the GMC to
> camp in while we did a couple roof jobs in Baldwin Mi.
> anyway, got back to Lansing after highway driving for
> over 150 miles and when it downshifted into low at a
> red light I couldnt get it to shift into third...the
> engine was revving pretty high and after a few minutes
> it did shift into high gear....I did try manual shifting
> which didn't help. Anyone have an idea???
> We are supposed to be going to Coldwater this weekend...
> Rob Teed 74 Painted Desert
>
> _____NetZero Free Internet Access and Email______
> http://www.netzero.net/download/index.html
 
Rob,

I'd check the modulator and it's vacuum line and hose connections - check
for vacuum leaks, soft/spongy hoses and transmission fluid leaking from the
vac. hose connection. The modulator should have manifold vacuum, 15-20 in @
idle.
I'm not an expert on 425s, just my thoughts.

Good luck,

Peter
77 Eleganza II
Colorado
- ----- Original Message -----
From: "robteed"
To: "Gmcmotorhome Org"
Sent: Thursday, July 13, 2000 11:06 PM
Subject: Re:GMC: Transmission problems

> Hi Guys,
> I just got back from a work trip...used the GMC to
> camp in while we did a couple roof jobs in Baldwin Mi.
> anyway, got back to Lansing after highway driving for
> over 150 miles and when it downshifted into low at a
> red light I couldnt get it to shift into third...the
> engine was revving pretty high and after a few minutes
> it did shift into high gear....I did try manual shifting
> which didn't help. Anyone have an idea???
> We are supposed to be going to Coldwater this weekend...
> Rob Teed 74 Painted Desert
>
> _____NetZero Free Internet Access and Email______
> http://www.netzero.net/download/index.html
>
 
On Fri, 14 Jul 2000 01:06:56 -0400 "robteed"
writes:
> Hi Guys,
> I just got back from a work trip...used the GMC to
> camp in while we did a couple roof jobs in Baldwin Mi.
> anyway, got back to Lansing after highway driving for
> over 150 miles and when it downshifted into low at a
> red light I couldnt get it to shift into third...the
> engine was revving pretty high and after a few minutes
> it did shift into high gear....I did try manual shifting
> which didn't help. Anyone have an idea???
> We are supposed to be going to Coldwater this weekend...
> Rob Teed 74 Painted Desert

I had the same thing happen and it turned out to be a leaky vacuum line
going into something in the Tranny. Modulator, maybe? It was a no charge
fix by Aamco.

David Lee Greenberg
The GMC Motorhome Registry
Dedicated To The Preservation of the Classic GMC Motorhome
http://www.GMCss.com/Registry.htm
http://www.Buskirk-RushRV/GMC-Registry/online-registry.htm
 
Thanks Dave,
I'm going to replace the modulator valve..maybe that will take care of the
problem.
Anyone got a part number??
TIA,
Rob Teed 74 Painted Desert

> -----Original Message-----
> From: owner-gmcmotorhome
> [mailto:owner-gmcmotorhome]On Behalf Of
> davegreenberg1
> Sent: Friday, July 14, 2000 6:19 PM
> To: gmcmotorhome
> Subject: GMC: Transmission problems
>
>
>
>
> On Fri, 14 Jul 2000 01:06:56 -0400 "robteed"

> > Hi Guys,
> > I just got back from a work trip...used the GMC to
> > camp in while we did a couple roof jobs in Baldwin Mi.
> > anyway, got back to Lansing after highway driving for
> > over 150 miles and when it downshifted into low at a
> > red light I couldnt get it to shift into third...the
> > engine was revving pretty high and after a few minutes
> > it did shift into high gear....I did try manual shifting
> > which didn't help. Anyone have an idea???
> > We are supposed to be going to Coldwater this weekend...
> > Rob Teed 74 Painted Desert
>
> I had the same thing happen and it turned out to be a leaky vacuum line
> going into something in the Tranny. Modulator, maybe? It was a no charge
> fix by Aamco.
>
>
> David Lee Greenberg
> The GMC Motorhome Registry
> Dedicated To The Preservation of the Classic GMC Motorhome
> http://www.GMCss.com/Registry.htm
> http://www.Buskirk-RushRV/GMC-Registry/online-registry.htm
>

_____NetZero Free Internet Access and Email______
http://www.netzero.net/download/index.html
 
Our transmission problems were well documented on this list last month
so I thought I would let you all know the resolution. First let me
thank everyone who helped or offered to help when we were having
problems. Larry Price in Atascadero, Gene Fisher in Livermore and Henry
Davis in Soquel all helped with suggestions, offers for lodging and
transportation and general encouragement. The Black List is a great
resource.

I was a little disappointed with Coach Net. They are our road service
which we contracted through FMCA. They found the closest "qualified"
service center instead of the closest "authorized" repair station. They
called several shops in the area and found one that said they "might be
able to take a look." When we suggested they keep looking, they found a
GMC truck dealer and dispatched a tow truck. The tow would haul the
GMC, but wanted to leave me, my wife and our foster son on the side of
the road while the road service would try to send a taxi to pick us up
at our expense.

Well, before this story gets way too long... We contracted with a
friend of our son's who lives in the area and owns a heavy duty towing
service to tow the GMC and carry the family back to town. We contacted
Dunn's Transmission in Memphis for a rebuilt and began looking for a
shop to perform the install. Dunn's was GREAT to work with. They
generally send the transmissions out two day air freight, but in our
situation they agreed to overnight. Tony Dunn was my primary contact.
We selected Villa Automotive and RV in San Luis Obispo, CA to do the
install. Villa and Dunn worked together very well when there were minor
adjustments and kept us out of the middle. We paid for the transmission
and freight in and Dunn's paid for freight on the core back to Memphis.
They did not even charge our credit card for the core charge. Villa was
even 25% less than they originally estimated for the removal and
replacement.

Things took longer than we expected (primarily due to July 4th weekend)
but we were happy with the results. The GMC ran great back to Seattle
and life is good again. After the credit card recovers a bit I will add
a transmission temp gauge. Is the DigiPanel the recommended way to go?
We will also install a speedometer correction box since the transmission
has the 3.50 drive gears.

Thanks again to everyone.

Eric Tipton
etipton
 
I am glad you made it home...... you were sort of in the tween section of
CA. but you did what I think I would have done,,,,,, get a tranny from Dunn..

gene

>Our transmission problems were well documented on this list last month
>so I thought I would let you all know the resolution. First let me
>thank everyone who helped or offered to help when we were having
>problems. Larry Price in Atascadero, Gene Fisher in Livermore and Henry
>Davis in Soquel all helped with suggestions, offers for lodging and
>transportation and general encouragement. The Black List is a great
>resource.
>
>I was a little disappointed with Coach Net. They are our road service
>which we contracted through FMCA. They found the closest "qualified"
>service center instead of the closest "authorized" repair station. They
>called several shops in the area and found one that said they "might be
>able to take a look." When we suggested they keep looking, they found a
>GMC truck dealer and dispatched a tow truck. The tow would haul the
>GMC, but wanted to leave me, my wife and our foster son on the side of
>the road while the road service would try to send a taxi to pick us up
>at our expense.
>
>Well, before this story gets way too long... We contracted with a
>friend of our son's who lives in the area and owns a heavy duty towing
>service to tow the GMC and carry the family back to town. We contacted
>Dunn's Transmission in Memphis for a rebuilt and began looking for a
>shop to perform the install. Dunn's was GREAT to work with. They
>generally send the transmissions out two day air freight, but in our
>situation they agreed to overnight. Tony Dunn was my primary contact.
>We selected Villa Automotive and RV in San Luis Obispo, CA to do the
>install. Villa and Dunn worked together very well when there were minor
>adjustments and kept us out of the middle. We paid for the transmission
>and freight in and Dunn's paid for freight on the core back to Memphis.
>They did not even charge our credit card for the core charge. Villa was
>even 25% less than they originally estimated for the removal and
>replacement.
>
>Things took longer than we expected (primarily due to July 4th weekend)
>but we were happy with the results. The GMC ran great back to Seattle
>and life is good again. After the credit card recovers a bit I will add
>a transmission temp gauge. Is the DigiPanel the recommended way to go?
>We will also install a speedometer correction box since the transmission
>has the 3.50 drive gears.
>
>Thanks again to everyone.
>
>Eric Tipton
>etipton

Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/ http://www.california.com/~eagle/
 
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