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#1 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Transmission Question
I need some "advice". I scored a 1971 GMC Custom Camper 2500 Series with 46K original miles and all original. On the glove box door it says M49 Turbo Hydra-Matic transmission. As I am going down the road I can feel it shift from what I presume is 1st... to 2nd(very smooth) to 3rd at around 30 MPH and it feels like it should shift once more at around 45 - 50 but it does not. Doing 55 MPH it seems as though the engine is pulling some substantial RPMs... should it be shifting one more time? What would keep it from going into that final gear... The truck runs and drives great except for this issue. It was bought brand new and when Grandpa passed he left it to his son. When his son couldn't drive anymore he turned the truck over to his daughter and that's who I got it from... she had it about 10 years.
Any assistance on this transmission shifting question will be greatly appreciated. Thank you |
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#2 |
Registered User
![]() Join Date: May 2007
Location: Rapid City South Dakota
Posts: 2,359
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Re: Transmission Question
Your trans only has 3 forward gears. Since it is a 3/4 ton, it may have 4.10 gears, which would make the engine rpm, higher than you are used to.
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Turp Mcspray New life for an old 2wd, farm blazer http://67-72chevytrucks.com/vboard/s...d.php?t=505987 My Blazer build http://67-72chevytrucks.com/vboard/s...d.php?t=342299 |
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#3 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Re: Transmission Question
I guess so then... what would be optimal gear ratio so that the engine is not working quite so hard at about 60 MPH?
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#4 |
Registered User
![]() Join Date: Jul 2012
Location: White Salmon, WA
Posts: 263
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Re: Transmission Question
Depends on rear tire size.
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#5 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,647
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Re: Transmission Question
And if you have an Eaton HO52, taller gears are not available. Well, maybe 3:73s but that's not much change. You'd have to swap to a different rear end. I'd start by verifying the ratio.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#6 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,118
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Re: Transmission Question
If no one has changed anything on the truck and it has the 350 engine you would have 4:10 gears and 4:57 were optional and would show on the spid label on the inside of the glove box lid. If you have a 402 engine you will have 3:54 gears and optional were 4:10s and that too will show up on the spid label. We all love to see pictures of trucks on here so if and when you can, post some pictures.
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#7 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Re: Transmission Question
I will post up some pictures for sure... Thanks all for the information... It is a 350 and nothing has been changed on this truck. Even still has the AM Radio in it, original carpeting. It's got some rust here and there but nothing like my '64...
On the glove box label it says "Turbo Hydra-Matic and under option it says N40 Thanks again and I welcome any and all advice... |
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#8 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Re: Transmission Question
Here are some pics from yesterday... I had to keep the '64 in the pictures so it didn't feel jilted...
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#9 |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,118
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Re: Transmission Question
Even sideways that is a great looking truck.
Posted via Mobile Device
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#10 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Re: Transmission Question
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#11 | |
70+ ( Old Skool Club )
![]() Join Date: Nov 2003
Location: Saskatoon, Saskatchewan ,Canada
Posts: 9,118
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Re: Transmission Question
Quote:
Posted via Mobile Device
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1972 C10 Custom/Deluxe 613 Highlander 406/700R4 1999 White Tahoe LS 4x2 with Z56 Police Package 1992 K1500 GMC Suburban Members I have personally met: MusicMan70 - HeavyD - ChewyChevy67 - StingRay -71SWB4x4 - 67 Burb - DeadheadNM - too much stuff - bc65 - das601 " Circumsatances Do Not Change Responsibility " " The Sky is not the Limit, Your Mind is." Marilyn Monroe .. RIP Charlie Watts 1941 - 2021 |
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#12 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,647
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Re: Transmission Question
Not sideways on my home computer.... truck looks great btw!
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#13 |
Registered User
Join Date: Jul 2013
Location: Dallas, GA
Posts: 30
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Re: Transmission Question
Cool. Weird. It does come up sideway on my iPad also. Thanks.
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1964 C10... work in progress 1971 GMC 2500 Sierra Custom Camper |
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#14 |
Registered User
Join Date: May 2013
Location: Central NC
Posts: 830
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Re: Transmission Question
Nice truck...saw your story about the naming it after the lady you got it from...you are a good man.
You can also change transmissions to one with overdrive to get your rpms down...or put on glass packs and enjoy the music!
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1972 Cheyene C-10 "Ole Green" My Grandfathers truck (early 70's to 1983) My first vehicle (1983) Original 350 (3 rebuilds) 700R4 from Bowtie Overdrives ![]() |
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