I just re-geared to 4.56's and am running 33's. Right now, my speedo is about 20-25 mph off. I know I need to change the speedo gear but I don't know what size to change it to or where to get one. I think I have a th-350 but I am not sure. How can I figgure that out as well? Thanks for your help.
CK5
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Speedo is WAAAAAYYYY off.
- Thread starter ajalecci
- Start date
Silver84k5
1/2 ton status
th350 has a square pan with one corner cut off, a th400 as a funky pan, 700r4 has a square pan....
Just go find your self one of those Police Speed survey/ticket/take your picture thing.... and find out how far its off, then just remember it ;P
Speedometers are overrated ;P
Just go find your self one of those Police Speed survey/ticket/take your picture thing.... and find out how far its off, then just remember it ;P
Speedometers are overrated ;P
my speedo doesnt work at all... honestly tho, I want it back. lol. I generally dont worry about speeding tickets... but it WOULD be nice to know if I was breaking the law at any given point. lol!
j
j
rampage
3/4 ton status
A 700r4 has overdrive and a th350 doesn't - look on your shift column.
The best way to determine your speed is to follow a friend on the highway while he is doing 60. Check what your speedo says. If it says 55 then it's 10% slow. Then just always add 10% to what your speedo says.
The best way to determine your speed is to follow a friend on the highway while he is doing 60. Check what your speedo says. If it says 55 then it's 10% slow. Then just always add 10% to what your speedo says.
Bubba Ray Boudreaux
1 ton status
[ QUOTE ]
I just re-geared to 4.56's and am running 33's. Right now, my speedo is about 20-25 mph off. I know I need to change the speedo gear but I don't know what size to change it to or where to get one. I think I have a th-350 but I am not sure. How can I figgure that out as well? Thanks for your help.
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Well since y'all got an '88, I would venture to guess you have a 700. The speedo gear is more than likely located in the tailshaft housing of the transfer case.
I just re-geared to 4.56's and am running 33's. Right now, my speedo is about 20-25 mph off. I know I need to change the speedo gear but I don't know what size to change it to or where to get one. I think I have a th-350 but I am not sure. How can I figgure that out as well? Thanks for your help.
[/ QUOTE ]
Well since y'all got an '88, I would venture to guess you have a 700. The speedo gear is more than likely located in the tailshaft housing of the transfer case.
Check out the local tranny shops, they probably have a bunch a gears laying around they'll let ya have for free. As for trying to figure out how much it is off, beg, borrow or steal a GPS for the most accurate reading. /forums/images/graemlins/smile.gif
It doesn't matter what tranny you have because the speedo gear is located in the Transfer case tailshaft. Otherwise your speedo would be off by about 2:1 (depending on T-case) when you are in low range.
For your calculations, account for any change in tire size from stock to present, as well as the gear ratio change. Gear ratios are exact, but tire diameters are often different from the rated size.
This has been covered in detail before. Here's where I posted some info:speedo gear thread This change is very easy to do and the gears are inexspensive to buy. It gets a little harder if you have to change the drive gear also, but it is still doable.
For your calculations, account for any change in tire size from stock to present, as well as the gear ratio change. Gear ratios are exact, but tire diameters are often different from the rated size.
This has been covered in detail before. Here's where I posted some info:speedo gear thread This change is very easy to do and the gears are inexspensive to buy. It gets a little harder if you have to change the drive gear also, but it is still doable.
Silver84k5
1/2 ton status
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It doesn't matter what tranny you have because the speedo gear is located in the Transfer case tailshaft.
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good point heh didnt even think of that.
It doesn't matter what tranny you have because the speedo gear is located in the Transfer case tailshaft.
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good point heh didnt even think of that.
Silver84k5
1/2 ton status
unless somone swapped stuff out, if you got in my truck and tried to put it in OD.. youd get pretty frustrated when OD never kicks in....... /forums/images/graemlins/thumb.gif
