| Transmission issues? [message #66151] |
Mon, 30 November 2009 17:27  |
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MangoMushroom
Messages: 67
Registered: August 2008
Location: Emeryville, CA
Karma: 0
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Took the coach with 3 friends and 2 dogs down the central coast of California over the Thanksgiving holiday... started having the following symptoms for the first time:
1. Occasionally, I would shift into 2nd gear manually to use the engine as brake. When I shift back into Drive, transmission seems to slip. Need to put it in Park, then back into Drive to get going again.
2. Sound of grinding/whirring noise, similar to what an r/c car might sound like, is constant, though exacerbated after downshifting then going back into Drive
3. dropped the tranny pan, filled with new fluid and filter. Did notice some fine glitter in the pan in the old fluid. No change in performance after new fluid added 
4. Acceleration has diminished... feels like I'm towing a toad 
5. Coach acts relatively well as long as I'm not asking for too much torque from the tranny. Made it home safe driving consistent speed down the highway. 
Coach has 110k miles... probably original transmission. Vacuum to tranny is fine
Am I right to believe these are all signs of a slipping transmission? If so, I've been led to believe that significant $$$ is the only way to solve this problem (trans rebuild)
Any tips, encouragement, and whiskey shots would be appreciated
Thanks!
****MangoMushroom
`76 GMC Birchaven named "Harvey"
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| Re: [GMCnet] Transmission issues? [message #66192 is a reply to message #66151] |
Mon, 30 November 2009 21:05  |
Gary Casey
Messages: 448
Registered: September 2009
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I'm afraid I can't give much encouragement. Yes, it looks like the clutches are starting to slip. One thing to remember is that the weak link in the THM 400/425 is the second overrun band - that's the one that is used when you manually shift to second while coasting.
Gary
Took the coach with 3 friends and 2 dogs down the central coast of California over the Thanksgiving holiday... started having the following symptoms for the first time:
1. Occasionally, I would shift into 2nd gear manually to use the engine as brake. When I shift back into Drive, transmission seems to slip. Need to put it in Park, then back into Drive to get going again.
2. Sound of grinding/whirring noise, similar to what an r/c car might sound like, is constant, though exacerbated after downshifting then going back into Drive
3. dropped the tranny pan, filled with new fluid and filter. Did notice some fine glitter in the pan in the old fluid. No change in performance after new fluid added :(
4. Acceleration has diminished... feels like I'm towing a toad :x
5. Coach acts relatively well as long as I'm not asking for too much torque from the tranny. Made it home safe driving consistent speed down the highway. :?
Coach has 110k miles... probably original transmission. Vacuum to tranny is fine
Am I right to believe these are all signs of a slipping transmission? If so, I've been led to believe that significant $$$ is the only way to solve this problem (trans rebuild)
Any tips, encouragement, and whiskey shots would be appreciated
Thanks!
--
****MangoMushroom
`76 GMC Birchaven
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| Re: Transmission issues? [message #66204 is a reply to message #66151] |
Mon, 30 November 2009 21:52 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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The only good thing I have to say is that one of the best people in the world of GMC transmissions is very close to you. (That would be Manny T.)
If you are going to keep the coach for any amount of time, bite the bullet and get it done right the first time.
| MangoMushroom wrote on Mon, 30 November 2009 15:27 |
... Am I right to believe these are all signs of a slipping transmission? If so, I've been led to believe that significant $$$ is the only way to solve this problem (trans rebuild) ...
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Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: [GMCnet] Transmission issues? [message #66228 is a reply to message #66204] |
Tue, 01 December 2009 00:34 |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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Senior Member |
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I see Manny's listing on Billy's site (hey, it's up again!) as follows:
Manny Trovao - Transmissions (including Switch Pitch) built
specifically for our motorhomes. 3.50:1 Power Drive chain and sprockets.
San Jose, CA 408-937-1583 mtrovao@hughes.net
On Nov 30, 2009, at 7:52 PM, Mike Miller wrote:
>
>
> The only good thing I have to say is that one of the best people in
> the world of GMC transmissions is very close to you. (That would be
> Manny T.)
>
> If you are going to keep the coach for any amount of time, bite the
> bullet and get it done right the first time.
> MangoMushroom wrote on Mon, 30 November 2009 15:27
>> ... Am I right to believe these are all signs of a slipping
>> transmission? If so, I've been led to believe that significant $$$
>> is the only way to solve this problem (trans rebuild) ...
>
> --
> Mike Miller
> `73 26' X Painted D.
> `78 23' Birchaven
> Hillsboro, OR
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: [GMCnet] Transmission issues? [message #66239 is a reply to message #66151] |
Tue, 01 December 2009 07:36 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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Senior Member |
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Your trans is dying. Time for a Manny Tranny. Replace it before you
trash the rebuildable core.
On Mon, Nov 30, 2009 at 4:27 PM, Andre Mandel <andre.mandel@gmail.com> wrote:
>
>
> Took the coach with 3 friends and 2 dogs down the central coast of California over the Thanksgiving holiday... started having the following symptoms for the first time:
>
> 1. Occasionally, I would shift into 2nd gear manually to use the engine as brake. When I shift back into Drive, transmission seems to slip. Need to put it in Park, then back into Drive to get going again.
>
> 2. Sound of grinding/whirring noise, similar to what an r/c car might sound like, is constant, though exacerbated after downshifting then going back into Drive
>
> 3. dropped the tranny pan, filled with new fluid and filter. Did notice some fine glitter in the pan in the old fluid. No change in performance after new fluid added :(
>
> 4. Acceleration has diminished... feels like I'm towing a toad :x
>
> 5. Coach acts relatively well as long as I'm not asking for too much torque from the tranny. Made it home safe driving consistent speed down the highway. :?
>
> Coach has 110k miles... probably original transmission. Vacuum to tranny is fine
>
> Am I right to believe these are all signs of a slipping transmission? If so, I've been led to believe that significant $$$ is the only way to solve this problem (trans rebuild)
>
> Any tips, encouragement, and whiskey shots would be appreciated
>
> Thanks!
> --
> ****MangoMushroom
> `76 GMC Birchaven
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
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