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#1 |
Navy Radioman Veteran
Join Date: Jul 2007
Location: Western Kentucky
Posts: 1,350
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Rear gears on an '87 R10 Silverado
Alright Gurus,
I'm trying to find out what gears are in the lowrider. I checked the differential and no tag that I could see. What were the options for my year truck? Thanks in advance. Kenny
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1987 Chevrolet R10 Silverado BBC Build thread - SOLD 1986 GMC Sierra Classic - SOLD 1957 Chevy Step Side - At the Body Shop Daily Driver; 2005 Chevrolet Silverado 4x4 Z71 Stepside |
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#2 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: Rear gears on an '87 R10 Silverado
A very good chance that they are 3.08 gears in that truck.
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#3 |
Registered User
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Location: New Orleans Louisiana.....a great place to visit but you wouldn't want to live here!!!
Posts: 883
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Re: Rear gears on an '87 R10 Silverado
Pull the diff. cover check the side of the ring gear, there will be numbers stamped on it. You are looking for numbers such as 41:10 you divide the small number into the large #...41:10 = 4.10. I agree the most common ratio is 3.08 but you never know if someone changed it. Beside's changing the diff fluid is not a bad thing! Just remember to add G.M. limited slip additive if your lucky enough to have a posi !!
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#4 |
www.73-87chevytrucks.com
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Location: Birmingham, AL
Posts: 6,935
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Re: Rear gears on an '87 R10 Silverado
2.76, 3.42, 3.73, 4.10...
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Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com |
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#5 |
Navy Radioman Veteran
Join Date: Jul 2007
Location: Western Kentucky
Posts: 1,350
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Re: Rear gears on an '87 R10 Silverado
ok.. I'll check it.
I know it's a pretty high gear. With the TH400 in there now, in 3rd, I'm only taching 1300-1400 RPM at arount 30-35 mph. If that's so, it should still be reasonable for cruizing at higher speeds. Chris - thanks for the options! Kenny
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1987 Chevrolet R10 Silverado BBC Build thread - SOLD 1986 GMC Sierra Classic - SOLD 1957 Chevy Step Side - At the Body Shop Daily Driver; 2005 Chevrolet Silverado 4x4 Z71 Stepside |
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#6 |
Registered User
Join Date: Feb 2007
Location: Austin, TX
Posts: 3,930
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Re: Rear gears on an '87 R10 Silverado
http://www.csgnetwork.com/speedcalc.html
Use that and your RPM at different speeds to figure out your ratio.
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1977 GMC Sierra Grande |
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#7 | |
Navy Radioman Veteran
Join Date: Jul 2007
Location: Western Kentucky
Posts: 1,350
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Re: Rear gears on an '87 R10 Silverado
Quote:
Ken
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1987 Chevrolet R10 Silverado BBC Build thread - SOLD 1986 GMC Sierra Classic - SOLD 1957 Chevy Step Side - At the Body Shop Daily Driver; 2005 Chevrolet Silverado 4x4 Z71 Stepside |
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#8 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: Rear gears on an '87 R10 Silverado
What size of tires are you running? The axle calcs will be easy.
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#9 |
Navy Radioman Veteran
Join Date: Jul 2007
Location: Western Kentucky
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Re: Rear gears on an '87 R10 Silverado
I dont' know overall height yet but the sizes are in my sig.
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1987 Chevrolet R10 Silverado BBC Build thread - SOLD 1986 GMC Sierra Classic - SOLD 1957 Chevy Step Side - At the Body Shop Daily Driver; 2005 Chevrolet Silverado 4x4 Z71 Stepside |
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#10 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: Rear gears on an '87 R10 Silverado
Well Pardner---you have 27.25" diameter tires on the front of the truck and 28.43" diameter tires on the back. The calculations tell me that the rear end is coming out at 3.3845, which is close to the 3.42 gears on a lot of trucks, so I would say that is where your at.
The difference in the calculations are probably due to the inaccuracies of what RPMs you have given for the actual speed on your speedo. There is a way to get the accurate readings on that also, but My guess is that you have a 3.42 rear end. |
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#11 | |
Navy Radioman Veteran
Join Date: Jul 2007
Location: Western Kentucky
Posts: 1,350
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Re: Rear gears on an '87 R10 Silverado
Quote:
![]() Still not a bad gear for cruizing and a little stop light to stop light action ![]() Thanks! Kenny
__________________
1987 Chevrolet R10 Silverado BBC Build thread - SOLD 1986 GMC Sierra Classic - SOLD 1957 Chevy Step Side - At the Body Shop Daily Driver; 2005 Chevrolet Silverado 4x4 Z71 Stepside |
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