Speedo to high???
Thread Starter
Pro
Joined: Aug 1999
Posts: 749
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From: Perth,Western Australia,Australia
Speedo to high???
When my speedo is at 70mph,I am in fact only doing 50mph,the transmission may have been changed at some stage,I'm not sure.I see in the CC catalogue that by an increase of one tooth you will slow it down by 5mph.
Anyone with a 79 TH350 rear gears 3.55-1 know what colour theirs is.
Thanks Neil.
Anyone with a 79 TH350 rear gears 3.55-1 know what colour theirs is.
Thanks Neil.
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Re: Speedo to high??? (Fleetwood)
Neil,
That's a very wide gap. I had one of ~8mph and solved it with a two-tooth change. Perhaps this site will give you some food for thought.
http://members.core.com/~faldrich/speedo.htm
That's a very wide gap. I had one of ~8mph and solved it with a two-tooth change. Perhaps this site will give you some food for thought.
http://members.core.com/~faldrich/speedo.htm
Thread Starter
Pro
Joined: Aug 1999
Posts: 749
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From: Perth,Western Australia,Australia
Re: Speedo to high??? (paul67)
Thanks for the web site Paul.I can only think that the tranny came out of a car with maybe 3.08 rear gears,not quite sure how to do the maths on this one.But as you say the gap is wide 20mph.
Neil.
Neil.
Drifting
Joined: May 2003
Posts: 1,634
Likes: 2
From: Melbourne, Victoria, Australia, the World
Re: Speedo to high??? (Fleetwood)
When my speedo is at 70mph,I am in fact only doing 50mph,the transmission may have been changed at some stage,I'm not sure.I see in the CC catalogue that by an increase of one tooth you will slow it down by 5mph.
Anyone with a 79 TH350 rear gears 3.55-1 know what colour theirs is.
Thanks Neil.
Anyone with a 79 TH350 rear gears 3.55-1 know what colour theirs is.
Thanks Neil.
My parts manual lists for 79 with 3.55 and TH350 a 3987922 driven gear with 22 teeth (gray).
The drive gear is 6261784 with 8 teeth (orange)
Check the number of teeth on both the drive and driven gear as there were 7 tooth drive gears available as well.
If the trans is from another car it may have different colors for the gears so count the teeth.
James
:cheers:
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Re: Speedo to high??? (Fleetwood)
Neil,
That is bizarre. My problem was a tire size change. I really cannot help you any further except to say that those gears are still available from GM and you do not have to waste money on "Corvette" gears.
That is bizarre. My problem was a tire size change. I really cannot help you any further except to say that those gears are still available from GM and you do not have to waste money on "Corvette" gears.
Drifting
Joined: May 2003
Posts: 1,634
Likes: 2
From: Melbourne, Victoria, Australia, the World
Re: Speedo to high??? (paul67)
Neil,
I really cannot help you any further except to say that those gears are still available from GM and you do not have to waste money on "Corvette" gears.
I really cannot help you any further except to say that those gears are still available from GM and you do not have to waste money on "Corvette" gears.
Just don't say "Corvette" to the parts guy!
:D :D
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Thread Starter
Pro
Joined: Aug 1999
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From: Perth,Western Australia,Australia
Re: Speedo to high??? (RHD '68 L89)
Thanks for the info James,I think I will take the gears out & check what they are.Going to a Holden dealer is a good idea,I'll take them with me when I go.
Neil. :cheers:
Neil. :cheers:
