I Swear This 1354 Made my Speedo Read Faster...

[Hahnsb2]

Well I've noticed after doing the 1354 swap my speedometer reads much faster than before. Now, it's always read fast since I'm on 31s with 4.10s with the stock 3.45 speedo gear. But it was saying I was pulling the sunset hill at 80 MPH last monday, I noticed tonight it hit 70 MPH (I'm talking indicated speeds, not actual) in 2nd at redline and 95 in 3rd redline, 3rd redline before was only around 75!!! Is there a difference with the internal speedometer gear between the 1350 and 1354? From what I can figure with some calculations it reads a total around 20% faster than actual speed (assuming my tach is correct).

 

[4x4junkie]

I experienced this also. I do believe the 1354 has more teeth on it's worm gear or something

I had planned on just swapping the 18 tooth gear out of my 1350 to replace the 17 on my 1354 and have it maybe be around 3-4 mph off instead of 6, but it wound up jumping to 8 off, even with the bigger gear. I had to go buy a 21T gear and it's still about 2 MPH fast.

 

[metalmacguyver]

Isnt the speedo gear paired with the gears/tire size as opposed to the case itself?

 

[MAKG]

There are at least two different sized worm gears in the BW transfer cases. I *think* they are 6 and 8 tooth. Check the math and see if it works.

If it confirms, you can calculate how many teeth you need on your new cable gear.

 

[rickcdewitt]

look at this
http://www.rrorc.com/forums/showthread.php?t=24206

 

[Hahnsb2]

Thanks guys. I believe a red speedo gear will get me close, I've got one laying around somewhere, might as well see what happens.

 

[Big Jim M]

look at this
http://www.rrorc.com/forums/showthread.php?t=24206

Thanks Rick
That is the best post I've ever seen about the damn speedo gears. The photo was great.
Big JIm

 

[fire57dan]

I also went to the 1354 and used the gear that was in the 1350 and it was yellow and is about 8 mph faster. The one in the 1354 was white so I dont think it will help me, I think a red one will work?

 

[rickcdewitt]

I also went to the 1354 and used the gear that was in the 1350 and it was yellow and is about 8 mph faster. The one in the 1354 was white so I dont think it will help me, I think a red one will work?

can you count the teeth on the white and yellow ones and post the tooth count when you get a chance?maybe theres another drive gear besides 6 and 7 tooth

 

[Sunk]

When I switched to the 1354 mine read waaay fast, like 30% or so (actual 50, reads 65). I switched to the gear that came with it which was for 3.55 gears. At the time I had 3.73s. Now with my 4.56s and 31s it reads about 15% fast.... so with 33s, it'll be a lot closer but not perfect.... I think the gear I'm using is white, and has 17 teeth?

 

[fire57dan]

I have the yellow (18), pink (19) and white (17) I just drove a documented 249.5 mile trip and my odometer read 255 miles with the white gear. Thats not too far off but my speedo seemed atleast 5-7 mph off. It seems like its ticking a bit too. I'll clean it out good before I get any new gears to try.

 

[AllanD]

With an older speedometer it's more than likely that if you adjust things so the odometer will read correctly the speedo won't and Vice-Versa.

the speedo is driven magnetically off the speedo cable
the odometer is directly driven by gears.

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[Hahnsb2]

It appears the 21 tooth gear put it very close (with my 31s).