Home » Public Forums » GMCnet » My tranny woes (all my fault :()
| Re: [GMCnet] My tranny woes [message #265529 is a reply to message #265523] |
Thu, 06 November 2014 00:21   |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Jim,
I did a cursory review of the transmission section of MM X-7525 but couldn't find any info on testing the transmission and where you
check the pump output pressure or how much pressure should be supplied at any given RPM.
A LOP switch could be wired in just to turn on a light and or buzzer when that pressure went too low.
I have a Digi-Panel that monitors the temperature and I would think that as the fluid level dropped the temp would go up. However,
by the time it went out of spec the transmission might already be toast.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: James Hupy
Kerry,
I was referring to the LOP switches that sense loss of pressure and open the ignition circuit. When they fail open, you have no
spark. Sorry if my answer was confusing.
Jim
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] My tranny woes [message #265531 is a reply to message #265523] |
Thu, 06 November 2014 02:46 |
cadelec
Messages: 303
Registered: September 2011
Location: Brisbane Australia
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i have just done a quick search on oil pressures for turbo 400 transmissions around 200 psi is what is being stated on the case pressure port and oil cooler lines down around 10-50 psi
so therefore any gauge or switch needs to be mounted in the pressure port I assume the 425 will have similar values
Originally Posted by Blown7 View Post
Like the title says, if I install a pressure gage in the oil cooler line, what should I see for a good pressure in a GM Turbo Hydro 400 transmission??
When? Idling, in gear? in park?? here's the factory spec:
neutral, brakes applied, 1k rpm: 55-70 psi
D, idle (idle "set to spec"): 60-85
D, brakes applied, 1k rpm: 60-90
Intermediate or lo, brakes
applied, engine at 1k rpm: 135-160
R, brakes applied, 1k rpm: 95-150
D, brakes applied, 1k rpm,
downshift switch activated: 90-110
this is for the oil pressure gauge mounted on the test port on the driver's side of the case. Hope it helps. *shrug*
http://www.pirate4x4.com/forum/general-4x4-discussion/848892-pressure-th400-oil-cooler-line.html
or this one
http://www.dragstuff.com/forum/viewtopic.php?f=16&t=4869
Trevor
Brisbane Australia
Siesta Koala 76 Edgemont (old Bobby Moores)
71 Cadillac Eldo Convert
58 Cadillac Eldorado Brougham Project
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| Re: [GMCnet] My tranny woes [message #265540 is a reply to message #265531] |
Thu, 06 November 2014 08:23 |
powerjon
Messages: 2446
Registered: January 2004
Karma: 5
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All,
Here is the trouble shooting manual for the transmission.
http://www.bdub.net/manuals/THM_425_Trouble_Shooting.pdf
JR Wright
78 Buskirk Stretch
75 Avion
Michigan
> On Nov 6, 2014, at 3:46 AM, Trevor Pordage wrote:
>
> i have just done a quick search on oil pressures for turbo 400 transmissions around 200 psi is what is being stated on the case pressure port and oil
> cooler lines down around 10-50 psi
> so therefore any gauge or switch needs to be mounted in the pressure port I assume the 425 will have similar values
>
>
> Originally Posted by Blown7 View Post
> Like the title says, if I install a pressure gage in the oil cooler line, what should I see for a good pressure in a GM Turbo Hydro 400
> transmission??
>
> When? Idling, in gear? in park?? here's the factory spec:
>
> neutral, brakes applied, 1k rpm: 55-70 psi
> D, idle (idle "set to spec"): 60-85
> D, brakes applied, 1k rpm: 60-90
> Intermediate or lo, brakes
> applied, engine at 1k rpm: 135-160
> R, brakes applied, 1k rpm: 95-150
> D, brakes applied, 1k rpm,
> downshift switch activated: 90-110
>
> this is for the oil pressure gauge mounted on the test port on the driver's side of the case. Hope it helps. *shrug*
>
> http://www.pirate4x4.com/forum/general-4x4-discussion/848892-pressure-th400-oil-cooler-line.html
>
> or this one
>
> http://www.dragstuff.com/forum/viewtopic.php?f=16&t=4869
>
>
>
>
>
> --
> Trevor
> Brisbane Australia
> Siesta Koala 76 Edgemont (old Bobby Moores)
> 71 Cadillac Eldo Convert
> 58 Cadillac Eldorado Brougham Project
>
> _______________________________________________
> GMCnet mailing list
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: My tranny woes [message #265570 is a reply to message #265389] |
Thu, 06 November 2014 17:19 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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The thing that is still not clear to me is what pressure is potential damaging at various RPM...mainly at road speed say 2500. I'm not sure but don't have a clue but if we set an alarm at 50 psi, it seems to me that perhaps 51 PSI might allow the tranny to be damaged????? I don't know.
Nor do I know if there is a direct relationship between PSI and fluid level?
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] My tranny woes [message #265575 is a reply to message #265570] |
Thu, 06 November 2014 17:59 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Check manual X-7525, page 7-13 and subsequent for pressure and use in
diagnosis. On page 7-21, the first reason given for low pressure is low
ATF. Sounds like a clue that a guage MIGHT be useful.
Ken H.
On Thu, Nov 6, 2014 at 3:19 PM, Kerry Pinkerton
wrote:
> The thing that is still not clear to me is what pressure is potential
> damaging at various RPM...mainly at road speed say 2500. I'm not sure but
> don't
> have a clue but if we set an alarm at 50 psi, it seems to me that perhaps
> 51 PSI might allow the tranny to be damaged????? I don't know.
>
> Nor do I know if there is a direct relationship between PSI and fluid
> level?
> --
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: My tranny woes [message #265825 is a reply to message #265394] |
Mon, 10 November 2014 21:02 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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kerry pinkerton wrote on Mon, 03 November 2014 19:39Bob what happens is the torque converter drains down and fills the bottom of the tranny which overflowed via the missing O-ring. From what I can determine, all converters leak down but some quicker than others. When I first noticed the problem, I was 2 quarts + low. Manny said no 425 can survive that.
Larry, I don't know about the parts list but Manny said that HF has a Viton O-ring assortment.
Good point--hadn't thought about the leak down but on the other hand do you think that is happening? I have not seen leak down being very common and it is usually obvious if you have no drive untill the engine has idled for a while. Regardless, sorry for your expensive failure !
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: My tranny woes [message #266333 is a reply to message #265389] |
Tue, 18 November 2014 16:01 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Progress of sorts...
Last week I drove down to Americus to pick up a new Manny Tranny that was stored there (there is only one left...contact Ken H for details). We swapped over my power drive sprockets and chains and I headed home. Yesterday, Manny told me I also needed the big plate behind the sprockets too. sigh... Oh well, Ken is taking it off my old tranny and sending it to me.
Since I have everything out and accessible...and since I'm going to redo the dash anyway...and since I have this 'thing' about knowing what is going on, I ordered some Steward-Warner gauges from http://Summitracing.com
- Two temp sender units 140 t 320 degrees SWW-280EE-F
- An oil temp gauge. SWW-82115
- An tranny fluid temp gauge. SWW-82344
- An oil pressure gauge with electric sender that will go in the tranny diagnostic port SWW-82136
- A gas gauge. SWW-82303
- A new 0-30 HG vacuum gauge SWW-82328
I'll pull the tranny pan and weld in a bung for the tranny sender and do the same on the oil pan while I have it off swapping out the oil pump for a high volume pump. This new tranny has a drain in the pan so I won't need to add one.
The tranny pressure will be something interesting to watch. Anything less than 50psi will warrant checking fluid level.
Yeah Yeah I know. Most of you have driven 16 jillion miles with nothing but the stock gauges. My take is that one one ever died from having too much information.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] My tranny woes [message #266340 is a reply to message #266333] |
Tue, 18 November 2014 16:54 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Kerry,
While you have the oil pump off you might want to match the mating half of the pump to the block.
http://www.gmcmhphotos.com/photos/back-at-jims/p7158.html
Here are some more photos that relate to the oil pump:
http://www.gmcmhphotos.com/photos/mechanical/p50094-oil-pump-housing.html
http://www.gmcmhphotos.com/photos/misc/p37898-patterson-oil-pump.html
http://www.gmcmhphotos.com/photos/melling-22fhv-oil-pump-pressure/p18205.html
I agree watching the tranny oil pressure will be interesting.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Kerry Pinkerton
Progress of sorts...
Last week I drove down to Americus to pick up a new Manny Tranny that was stored there (there is only one left...contact Ken H for
details). We swapped over my power drive sprockets and chains and I headed home. Yesterday, Manny told me I also needed the big
plate behind the sprockets too. sigh... Oh well, Ken is taking it off my old tranny and sending it to me.
Since I have everything out and accessible...and since I'm going to redo the dash anyway...and since I have this 'thing' about
knowing what is going on, I ordered some Steward-Warner gauges from http://Summitracing.com
- Two temp sender units 140 t 320 degrees SWW-280EE-F
- An oil temp gauge. SWW-82115
- An tranny fluid temp gauge. SWW-82344
- An oil pressure gauge with electric sender that will go in the tranny diagnostic port SWW-82136
- A gas gauge. SWW-82303
- A new 0-30 HG vacuum gauge SWW-82328
I'll pull the tranny pan and weld in a bung for the tranny sender and do the same on the oil pan while I have it off swapping out
the oil pump for a high volume pump. This new tranny has a drain in the pan so I won't need to add one.
The tranny pressure will be something interesting to watch. Anything less than 50psi will warrant checking fluid level.
Yeah Yeah I know. Most of you have driven 16 jillion miles with nothing but the stock gauges. My take is that one one ever died
from having too much information.
Kerry
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] My tranny woes [message #266348 is a reply to message #266340] |
Tue, 18 November 2014 18:27 |
kerry pinkerton
Messages: 2565
Registered: July 2012
Location: Harvest, Al
Karma: 15
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Senior Member |
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USAussie wrote on Tue, 18 November 2014 16:54Kerry,
While you have the oil pump off you might want to match the mating half of the pump to the block. ...
By match, what exactly do you mean?, verify there is the mating surfaces match by using DYKEM and a file? Or matching the openings?
Btw, Dick Paterson also recommended, and I bought the MILODAN #22575 high volume oil pump shaft. Also got the +4 degrees timing chain set and will be installing that also. I'll cover that in a new thread.
Kerry Pinkerton - North Alabama
Had 5 over the years. Currently have a '06 Fleetwood Discovery 39L
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| Re: [GMCnet] My tranny woes [message #266350 is a reply to message #266348] |
Tue, 18 November 2014 18:50 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Kerry,
I VAGUELY remembered a discussion about matching the oil pump and block mating surfaces on the GMCnet God knows when.
I did a search of the Photosite and found:
http://www.gmcmhphotos.com/photos/back-at-jims/p7158.html
As you can see it was posted Mon April 23, 2007.
To me it looks like you match them with Dykem and a rotary file in a Dremel?
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Kerry Pinkerton
USAussie wrote on Tue, 18 November 2014 16:54
> Kerry,
>
> While you have the oil pump off you might want to match the mating half of the pump to the block. ...
By match, what exactly do you mean?, verify there is the mating surfaces match by using DYKEM and a file? Or matching the openings?
Btw, Dick Paterson also recommended, and I bought the MILODAN #22575 high volume oil pump shaft. Also got the +4 degrees timing
chain set and will be installing that also. I'll cover that in a new thread.
--
Kerry
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: My tranny woes [message #266354 is a reply to message #265389] |
Tue, 18 November 2014 19:37 |
lotsofspareparts
Messages: 726
Registered: May 2014
Location: Arlington, WA
Karma: -9
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I'm never driving my coach again.....
Sorry for your tranny troubles.
Manny will set it right.
Hard to believe that it could be the O-ring on the dipstick of all things.
Jared.
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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| Re: My tranny woes [message #266360 is a reply to message #266354] |
Tue, 18 November 2014 21:51 |
rickmike
Messages: 252
Registered: September 2011
Location: United States
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The pressure would not be affected by fluid level until the pump sucks air.
Otherwise the only effect fluid level would have would be heat transfer.
You need enough mass of fluid to transfer the heat properly.
Fluid level could be inferred by temperature for a given operating condition.
Say, if you are driving on level ground at 60 mph with an outside temp of 70F.
and the next time you are driving the same conditions and the temp is higher, you could imply that the fluid level is lower.
Of course, A lower fluid level would likely cause a higher temp and this would decrease the viscosity and may show a slight decrease in pressure.
Rick M.
1974 26' Canyonlands
aka "The General"
Clinton, TN
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| Re: My tranny woes [message #267892 is a reply to message #265389] |
Fri, 19 December 2014 20:01 |
rcjordan
Messages: 1913
Registered: October 2012
Location: Elizabeth City, North Car...
Karma: 1
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I need a tranny diptube o-ring as the Birchaven has shown telltale pools of fluid while sitting on the slab. My search turned up the following part numbers
44371A O-Ring, GM / Ford / Chrysler Filler tube
A904 (TF6)
Mopar Part Number: 6030608
SOLD 77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
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| Re: [GMCnet] My tranny woes [message #267896 is a reply to message #267892] |
Fri, 19 December 2014 20:37 |
sgltrac
Messages: 2797
Registered: April 2011
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Is there a question hidden in there?
Todd Sullivan
Sully
77 royale
Seattle
> On Dec 19, 2014, at 6:01 PM, RC Jordan wrote:
>
> I need a tranny diptube o-ring as the Birchaven has shown telltale pools of fluid while sitting on the slab. My search turned up the following part
> numbers
>
> 44371A O-Ring, GM / Ford / Chrysler Filler tube
> A904 (TF6)
> Mopar Part Number: 6030608
>
> --
> 77 Royale Coachmen Side Dry Bath
> 76 Birchaven Coachmen Side Wet Bath
> Elizabeth City, NC
>
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Sully
77 Royale basket case.
Future motorhome land speed record holder(bucket list)
Seattle, Wa.
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| Re: My tranny woes [message #267897 is a reply to message #265389] |
Fri, 19 December 2014 20:48 |
rcjordan
Messages: 1913
Registered: October 2012
Location: Elizabeth City, North Car...
Karma: 1
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A confirmation would be good.
SOLD 77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
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| Re: My tranny woes [message #267908 is a reply to message #265389] |
Fri, 19 December 2014 23:20 |
rcjordan
Messages: 1913
Registered: October 2012
Location: Elizabeth City, North Car...
Karma: 1
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See that "A904" ? If that is a reference to the as568 standard, then we'll know the size and can maybe get it in viton.
Scroll waaaay down http://www.marcorubber.com/sizingchart.htm
SOLD 77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
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| Re: My tranny woes [message #268510 is a reply to message #265389] |
Tue, 30 December 2014 11:24 |
rcjordan
Messages: 1913
Registered: October 2012
Location: Elizabeth City, North Car...
Karma: 1
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The o-ring sizing cone arrived today. If the above cross-referenced tranny o-ring is correct (I'm not installing this until I can come up with a viton replacement), it appears to be a dash size 113. Viton 5-pack ordered
http://www.amazon.com/dp/B000FMYQCQ/
SOLD 77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
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