Rear gears on an '87 R10 Silverado

[87Lowrider]

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

[piecesparts]

A very good chance that they are 3.08 gears in that truck.

[crawdadfox]

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 !!

[Captkaos]

2.76, 3.42, 3.73, 4.10...

[87Lowrider]

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

[Pyrotechnic]

http://www.csgnetwork.com/speedcalc.html

Use that and your RPM at different speeds to figure out your ratio.

[87Lowrider]

Originally Posted by Pyrotechnic

http://www.csgnetwork.com/speedcalc.html

Use that and your RPM at different speeds to figure out your ratio.

Thanks... I'll play with it and see what happens!

Ken

[piecesparts]

What size of tires are you running? The axle calcs will be easy.

[87Lowrider]

Originally Posted by piecesparts

What size of tires are you running? The axle calcs will be easy.

I dont' know overall height yet but the sizes are in my sig.

[piecesparts]

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.

[87Lowrider]

Originally Posted by piecesparts

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.

Cool - who am I do disagree!

Still not a bad gear for cruizing and a little stop light to stop light action

Thanks!


Kenny