Anonymous
Unregistered
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Hi all,
For those of you who have put larger tires on your Montero's, what type of speedo gear change did you use. I am putting 33's on and would like the Odo and Speedo to still be accurate. Can you recommend any vendors?
DougB: I noticed in the part number repository that you listed different gears for the Gen I.. do you know if they are also avail for the Gen II.5'?
TIA,
Shoe
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4xmonty
Body Damage is Cool
Reged: 08/13/04
Posts: 1410
Loc: Vallejo Ca
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Need info on your vehicle,add this to your signature
Russ
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GETTIN OLD THATS EARNED
Happy trails to you
(1)98 Montero SR RB Rock Crawlers BFG 33s Rancho 9000's OME Med coils rear
(2)95 4Runner All Pro Nerf bars BFG 32s
ARB bull bar
Downey 2" rear coils Downey headers
(3) 90 Montero LWB 3.0 auto
(4) 98 Kawi GPZ1100
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Anonymous
Unregistered
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I have a 1999 Monty (wide fender) 4spd auto. Looking at the CAPS program I may have an electronic speed control:
Look at P/N 82852.. at the bottom. Says: Sensor, Vehicle Speed.
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4xmonty
Body Damage is Cool
Reged: 08/13/04
Posts: 1410
Loc: Vallejo Ca
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Quote:
I have a 1999 Monty (wide fender) 4spd auto. Looking at the CAPS program I may have an electronic speed control:
Look at P/N 82852.. at the bottom. Says: Sensor, Vehicle Speed.
You do
Russ   
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GETTIN OLD THATS EARNED
Happy trails to you
(1)98 Montero SR RB Rock Crawlers BFG 33s Rancho 9000's OME Med coils rear
(2)95 4Runner All Pro Nerf bars BFG 32s
ARB bull bar
Downey 2" rear coils Downey headers
(3) 90 Montero LWB 3.0 auto
(4) 98 Kawi GPZ1100
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Anonymous
Unregistered
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Well, that will be easier.... 
Link #1 "YellR"
Link # 2 Dakota
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fasteddy
Web Wheeler
Reged: 01/30/01
Posts: 12703
Loc: Flat Creek, GA
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Yes, you have a vehicle speed sensor, but it doesn't drive the speedo. It generates a speed dependent frequency voltage signal to the ecu for fuel control (decel fuel cut) and to the cruise control speed input.
The speedo is cable driven, and you need a different count speedo drive gear that goes in the speedo cable attachment assembly at the tranny/transfer case at the under car end of the speedo cable. The different gears have different tooth counts, and are retained in the housing by a driven roll pin, and sealed with an oring. Housing is held in place with one nut on a stud holding a metal fork that presses the housing into the tranny case, also sealed with an oring. Remove cable feom housing. remove housing from tranny. count gear teeth. Say count is 26. Measure center of axle to ground on old rear tires. Measure same on new tires. divide a into b. if old tires are 31, measurement will be about 15.5, and new will be about 16.5, and division would yield about 1.065. DIVIDE 1.065 into 26 tooth count - 24.42 teeth required on new driven gear, so you buy a 24 tooth new gear from Mitsu. Most all mitsu's with cable use the same fitting gears, and the hard part is finding the right model to look up. Might try 2wd late pickups with the 4.222 diff. Use new orings, too.
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"If you can't be a good influence, don't worry, you can still be a horrid example."
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TommyM
Rock Warrior
Reged: 02/07/04
Posts: 568
Loc: Durango, CO
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I'd agree with FE on the math, with one caveat. Instead of measuring from the center of the axle to the ground, it's easier to get a more accurate measurement if you measure the circumference of the tire. Either use a flexible tape measure, or use a piece of string, then measure the string.
New tire circumference/old tire circumference = new speedo gear # of teeth/old speedo gear # of teeth.
So new speedo gear # of teeth = Old gear # of teeth x (new circ/old circ).
Right?
Tommy
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90 LWB Montero, 270k, 265/75R16, 16x8 ARE Bajas, Budget Lift, Towbar, Aux Brakes (towed with camper), Jotto Desk, remote oil filter
92 bone stock base model beater
Parting out 4 more
Edited by TommyM (02/02/07 06:18 PM)
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Anonymous
Unregistered
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Aw Shux...
Here I thought I would get off easy. 
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NathanC
Roll Me Over
Reged: 04/22/02
Posts: 3620
Loc: Brodhead, WI
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Quote:
The speedo is cable driven, and you need a different count speedo drive gear that goes in the speedo cable attachment assembly at the tranny/transfer case at the under car end of the speedo cable.
I beg to differ. My SR is strictly elecric. No cable whatsoever.
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'06 Dakota QC 4.7 6sp 4x4
'94 Montero SR back to stock
'88 Mighty Max project for sale
'77 KZ1000 fun old bike
'60 Dodge D300
If anyone is not willing to work, then he is not to eat, either. - 2Thess. 3:10b
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fasteddy
Web Wheeler
Reged: 01/30/01
Posts: 12703
Loc: Flat Creek, GA
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Tommy, your way would work, but I think you get a more accurate measurement, because the rolling radius is less than the circumference divided by pi, because the radius is compressed by vehicle weight while rolling. My method misses any Raidius (sic) swell due to centripetal force as the tire spins, but it misses both on old and new diameters, partially cancelling out the error. Measuring circumference also throws pi in as an error exagerator. I've probably made some errors in logic here, as I didn't measure and check myself out, but I'm more comfortable with my errors than yours. Probably just chauvinism - "T'weren't invented hyar!"...
And after we argued this one, we can argue about torque wrenches again, and going wrong with confidence....
I said cable driven due to the CAPS diagram. Sure looks like a speedo cable to me.
Note that most spinning magnet speedos (almost all the cable driven ones) have some kind of counter spring adjustment in the speedo. I think one of the Dougs found it on ours. I'm not as happy with this adjustment as the gear change, but both together should get you REAL close.
My 89 on 31-10.50-15's is off by 1.1mph low at 70 with no gear mods. Since most speedos are off showing higher than actual speed from the factory, the tire size change just decreased the original absolute error, and changed the error sign.
Since there's two speedo cable nut things on the CAPS, one of which is obviously a cable, and the other a 4 pole plug, are there two different speedo drive systems depending on model? Do the Gen2's have two VSS's like the Gen1's? Gen1 has a VSS on the tail end of the tcase front output shaft for the magic "LOCKED" light controlling comparator, and another (reed switch) in the back side of the speedo for the ecu and cruise.
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"If you can't be a good influence, don't worry, you can still be a horrid example."
Edited by fasteddy (02/02/07 09:39 PM)
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