Overdrive not possible to engage at 10 MPH.

Fernando Mendes · Post by **Fernando Mendes** » Mon Jan 22, 2007 4:18 pm

I have another question.Is it possible to engage the overdrive(fifth) running at 10 MPH? To correctly engage of this is necessary that I go running at 30 to 45 MPH?Any help is welcome.

Degsy · Post by **Degsy** » Mon Jan 22, 2007 4:34 pm

Whilst it is possible to engage fifth gear at 10mph it is not possible for the truck to run at this low speed and could cause damage.

John V Cliche · Post by **John V Cliche** » Mon Jan 22, 2007 6:50 pm

Hi Fernando
Degsy right if you lug your engine to that low of an rpm you run the risk of damaging the engine and in all likelyhood it would certainly stall.Not to mention you having to slip the clutch as well
But if you wait to engage 5th gear at 45mph you will certainly blow up that 270!!!
It seems to me that you should probably be near the 25+/-mph range.Let the engine decide what gear it needs, because it depends a lot on operating conditions ie; load , grade.

Hope this helps
John

armydriver · Post by **armydriver** » Mon Jan 22, 2007 8:50 pm

John is right on with his assesment. Let the engine tell you what gear it needs. The more you drive your truck the more you and the engine will be in tune with each other. Happy driving and keep em rolling.

Fernando Mendes · Post by **Fernando Mendes** » Sat Nov 13, 2010 5:43 am

Ok guys.After three years,nine months and twenty one days I and my craftsman withdrew my transmission box.Looking to the gears we noticed that the 5th and 3rd gears are all uneven

.We don't desmount still the main and second shafts,but we are thinking that there aren't the 3rd rollings(31),nor 3rd two washers,nor 5th bushing.

After I will keep you informed.

Fernando Mendes · Post by **Fernando Mendes** » Sun Nov 14, 2010 6:10 pm

http://img687.imageshack.us/img687/7955 ... udana1.png
http://img844.imageshack.us/img844/3879 ... udana2.png

Nice to see and print.

Fernando Mendes · Post by **Fernando Mendes** » Tue Nov 16, 2010 2:52 pm

http://yfrog.com/evimagem274bj

I open my transmission case and noticed that was faulting one of the mainshaft 3rd speed gear washer.That was because broken the mainshaft 5th speed gear retaining washer.

Fernando Mendes · Post by **Fernando Mendes** » Wed Nov 17, 2010 10:25 am

Hi doctor deuce.Finally we desmounted the transmission last friday.The cause of not engaging the fifth gear since 2005 was not its fork.The cause is the fault of one of the two washers of the 3rd mainshaft gear.It is because broken the castled washer of the 5th mainshaft gear.Regards.

Fernando Mendes · Post by **Fernando Mendes** » Mon Nov 22, 2010 5:32 pm

http://img46.imageshack.us/img46/8798/cckwfifthclip.jpg
http://img713.imageshack.us/img713/9850 ... roblem.jpg

Fernando Mendes · Post by **Fernando Mendes** » Tue Nov 23, 2010 4:51 pm

http://img517.imageshack.us/img517/9426/imagem276n.jpg
http://img404.imageshack.us/img404/6222/imagem277.jpg
http://img217.imageshack.us/img217/6995/imagem274w.jpg
http://img831.imageshack.us/img831/6571/imagem281.jpg
http://img217.imageshack.us/img217/7585/imagem283o.jpg

Finnaly we finished the assembly of the transmission today.We had more dificult because some parts weren't original,but we had to improve.

Fernando Mendes · Post by **Fernando Mendes** » Wed Nov 24, 2010 4:25 pm

Anyone in this forum have this same problem in your GMC CCKW?

The GMC CCKW

Overdrive not possible to engage at 10 MPH.

Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.

Re: Overdrive not possible to engage at 10 MPH.