Speedometer way off!..and third gear rpm question
#962346
03/30/11 11:39 AM
03/30/11 11:39 AM
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Joined: Oct 2010
Posts: 576 Hr up from KCK
451 D*O*D*G*E
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mopar
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mopar
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Posts: 576
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My Chall has 255/60/15's on the rear,auto and sure grip .First off my spedo is 20mph off till about 50 then climbs to 30 miles off consistantly.At 75 on the GPS my speedo is on 120.Any ideas??Alos guy i bought the car from claims it has 3.91's but 4000rpm's at 70 mph seem right??.Thats flat azz screamin!Thanks for any help.
1970 Challenger R/T clone
2010 Dodge Journey R/T black,awd,
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Re: Speedometer way off!..and third gear rpm question
[Re: 451 D*O*D*G*E]
#962353
03/30/11 03:00 PM
03/30/11 03:00 PM
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Joined: Jan 2003
Posts: 26,005 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 26,005
Rio Linda, CA
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With 255/60/15's and 3.91 gears you need a 38-tooth speedo pinion. (Color blue P/N 52068060)
The INTERNET, the MISinformation superhighway
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Re: Speedometer way off!..and third gear rpm question
[Re: John_Kunkel]
#962354
03/30/11 08:36 PM
03/30/11 08:36 PM
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Joined: Oct 2010
Posts: 576 Hr up from KCK
451 D*O*D*G*E
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Ok,i'll order that one.What is the setting on the trans for,fine tuning?Still 4000 at 70 on the GPS..i'll get the wife to follow me out the highway some night.Dont know the accuracy of the gps.Thanks again.
1970 Challenger R/T clone
2010 Dodge Journey R/T black,awd,
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Re: Speedometer way off!..and third gear rpm question
[Re: 451 D*O*D*G*E]
#962355
03/30/11 08:51 PM
03/30/11 08:51 PM
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Joined: Nov 2007
Posts: 21,847 Kirkland, Washington
Pacnorthcuda
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Too Many Posts
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Posts: 21,847
Kirkland, Washington
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Quote:
Ok,i'll order that one.What is the setting on the trans for,fine tuning?
If you mean the clocking of the pinion housing....no. Its because pinions with more teeth are larger than those with less. The 'center' hole in the housing is not centered, for that reason. Correct clocking will ensure correct tooth engagement with the worm gear portion of the output shaft of the tranny. It has no 'fine-tuning' effect whatsoever.
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Re: Speedometer way off!..and third gear rpm question
[Re: Golden-Arm]
#962359
03/30/11 09:51 PM
03/30/11 09:51 PM
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Joined: Oct 2010
Posts: 576 Hr up from KCK
451 D*O*D*G*E
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I just never messed with that part of the housing other than taking the speedo cable off..thanks for all the help i have a manual valvebody and i am definetly getting into third. just take her car and the gps, and see for yourself. you'll know in a matter of seconds, if it's accurate.Yeah it works great but didnt know if a gps can be affected by weather.Dont know much about them.Her Edge and Garmin are dead on together. Appreciate the help..been into Mopars since '91 striaght through and definetly dont know everything,even some simple stuff like this which was foriegn to me.I enjoy learning..so much appreciated men.
1970 Challenger R/T clone
2010 Dodge Journey R/T black,awd,
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Re: Speedometer way off!..and third gear rpm question
[Re: kenworth_goose]
#962361
03/30/11 09:55 PM
03/30/11 09:55 PM
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Joined: Apr 2010
Posts: 1,216 Under My Car
Mopar_Country
pro stock
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pro stock
Joined: Apr 2010
Posts: 1,216
Under My Car
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Quote:
You've got a set of 4.56's.
That's what I'm thinkin'.
Let us know what you find out, inquiring minds want to know.
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Re: Speedometer way off!..and third gear rpm question
[Re: Mopar_Country]
#962362
03/31/11 09:34 AM
03/31/11 09:34 AM
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Joined: Jan 2003
Posts: 24,562 Brookeville, Md
Mr.Yuck
Not enough dumb comments...yet
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Not enough dumb comments...yet
Joined: Jan 2003
Posts: 24,562
Brookeville, Md
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Quote:
Quote:
You've got a set of 4.56's.
That's what I'm thinkin'.
Let us know what you find out, inquiring minds want to know.
I think he counted the rotation of the wheel vs. the driveshaft. He said it went almost 4 complete turns.
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Re: Speedometer way off!..and third gear rpm question
[Re: John_Kunkel]
#962363
03/31/11 10:25 AM
03/31/11 10:25 AM
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Joined: Jan 2003
Posts: 16,123 Grand Haven, MI
patrick
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
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without converter slip, 70mph with those tires and gears is 3400, I'd expect actual cruise RPM to be 3600-3700...the loose converter might be slipping more, getting up to 3800-3900....
275/60R15's drop that 100 RPM.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
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Re: Speedometer way off!..and third gear rpm question
[Re: patrick]
#962364
03/31/11 10:49 AM
03/31/11 10:49 AM
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Joined: Oct 2010
Posts: 576 Hr up from KCK
451 D*O*D*G*E
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Yeah i put her on stands and marked the driveshaft on the bottom and the inner pass side tire so i could spin drivers and read the other side..just barely 4 so we know the ratio..so the converter is possible not locking up all the way?..maybe?Wow i think the best thing for me to do is a make a video and post in car of Garmin and my tack readings and the fact you cant hold a conversation with full exhaust at 70mph . I'll try to put this together today and get back on here..week of vacation has been fun..couple honeydoo's to do but after that i'll try to get video put together...stay tuned...
1970 Challenger R/T clone
2010 Dodge Journey R/T black,awd,
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