A couple of new problems
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Laughing Gas
Joined: Oct 2010
Posts: 997
Likes: 2
From: Rock Valley, IA
A couple of new problems
Hello everyone.
After getting the transmission back on and the exhaust hung I was finally able to get it out on the road. This is where I found a couple of new problems I was hoping I could get some advice on.
1) When I get to I'm guessing 25-30mph (see problem 2) the truck vibrates really badly. I think I've isolated this to the front driveshaft, specifically the carrier or hanger bearing, or the rear end. The truck has two driveshafts. One stabilized by the hanger bearing and the second that goes from the front driveshaft to the rear differential.
2) I have no idea how fast I'm really going. I think I got the wrong gear for the speedometer. I was wondering if anyone knew how many teeth the T18 transmission speedometer gears have and what the standard differential ratio is? If I have those two pieces of info I can get the correct gear.
Thanks again for all your help.
After getting the transmission back on and the exhaust hung I was finally able to get it out on the road. This is where I found a couple of new problems I was hoping I could get some advice on.
1) When I get to I'm guessing 25-30mph (see problem 2) the truck vibrates really badly. I think I've isolated this to the front driveshaft, specifically the carrier or hanger bearing, or the rear end. The truck has two driveshafts. One stabilized by the hanger bearing and the second that goes from the front driveshaft to the rear differential.
2) I have no idea how fast I'm really going. I think I got the wrong gear for the speedometer. I was wondering if anyone knew how many teeth the T18 transmission speedometer gears have and what the standard differential ratio is? If I have those two pieces of info I can get the correct gear.
Thanks again for all your help.
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
Driveline vibration: check to insure all 3 u-joints are "clocked" the same way, as in all the caps line up. If they aren't lined up, severe vibration will occur.
Speedo gear: there is no "standard diff ratio". Was this a trans swap? The old speedo gear should have had the correct number of teeth, unless the rear diff was swapped to a different ratio at some point in the past.
What you'll need to do if the old gear is not available to check, is figure out how far off the speedo reads as well as if it reads fast or slow. Pull the current gear to count the teeth. Then, add more teeth to slow it down, or subtract teeth to speed it up.
Speedo gear: there is no "standard diff ratio". Was this a trans swap? The old speedo gear should have had the correct number of teeth, unless the rear diff was swapped to a different ratio at some point in the past.
What you'll need to do if the old gear is not available to check, is figure out how far off the speedo reads as well as if it reads fast or slow. Pull the current gear to count the teeth. Then, add more teeth to slow it down, or subtract teeth to speed it up.
Thread Starter
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Laughing Gas
Joined: Oct 2010
Posts: 997
Likes: 2
From: Rock Valley, IA
Thanks rogue. No, this wasn't a transmission swap. I took the trany out to seal up an oil leak behind the bell housing. I didn't realize that about the caps. I'll definitely check that tonight. I replaced the speedo gear as the old one was chewed up pretty bad. It was the maroon 21 tooth gear. It reads, I'm guessing, 10mph slow right now. I'll verify this with my wife in a pace car to see where I'm at. I'm guessing I'll have to subract teeth. Maybe to a 17. Is there any way to count the teeth in the trany without having to take the transmission down again?
Thread Starter
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Laughing Gas
Joined: Oct 2010
Posts: 997
Likes: 2
From: Rock Valley, IA
Gary, the gear that is in there now is the maroon one. It's still showing slow. So, I'll have to get a new one with fewer teeth.
As to the vibration, I took it to a shop that had a hoist and it turns out the rear drive shaft is bent. There's a place close by that can (hopefully) straighten it. If not, I guess I'll have to visit the local pull your part place to find a "new" one. I guess, all in all, it could be a worse diagnosis.
As to the vibration, I took it to a shop that had a hoist and it turns out the rear drive shaft is bent. There's a place close by that can (hopefully) straighten it. If not, I guess I'll have to visit the local pull your part place to find a "new" one. I guess, all in all, it could be a worse diagnosis.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Here's a link to info on speedo gears, formulae, etc: Speedometer Gear Color Code Specification Chart With Formulas, And Ford Part Numbers. - Ford Explorer Ranger Enthusiasts "Serious Explorations"® I'm sure our forum has the same info but this is what turned up first in a search.
And, this is an extraction of the pertinent info. Note that there is no "maroon", although I think the ATF changes the colors.
Auto Transmissions:
16-teeth-blue (D0AZ-A)
17-teeth-green (C7SZ-A)
18-teeth-gray (C7SZ-B)
19-teeth-tan (C7VY-A)
20-teeth-orange (C8SZ-B)
21-teeth-purple (D0OZ-B)
Then Use This Formula:
New Teeth = (Current Teeth x Speedo Reading)/Actual Speed.
And, this is an extraction of the pertinent info. Note that there is no "maroon", although I think the ATF changes the colors.
Auto Transmissions:
16-teeth-blue (D0AZ-A)
17-teeth-green (C7SZ-A)
18-teeth-gray (C7SZ-B)
19-teeth-tan (C7VY-A)
20-teeth-orange (C8SZ-B)
21-teeth-purple (D0OZ-B)
Then Use This Formula:
New Teeth = (Current Teeth x Speedo Reading)/Actual Speed.
Thread Starter
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Laughing Gas
Joined: Oct 2010
Posts: 997
Likes: 2
From: Rock Valley, IA
While helpful, it doesn't really apply. I have a 4-speed manual transmission and there is a maroon speedo gear. I just ordered a set of 5 from eBay so I should be able to find the right one. The maroon gear is a 16 tooth gear.
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FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Oops, my bad. Here's the manual tranny info from that link:
Manual Transmissions:
16-teeth-wine (C0DZ-A)
17-teeth-white (C3DZ-C)
18-teeth-yellow (C0DD-B)
19-teeth-pink (C0DZ-B)
20-teeth-black (C1DZ-A)
21-teeth-red (C4OZ-A)
Auto Transmissions:
16-teeth-blue (D0AZ-A)
17-teeth-green (C7SZ-A)
18-teeth-gray (C7SZ-B)
19-teeth-tan (C7VY-A)
20-teeth-orange (C8SZ-B)
21-teeth-purple (D0OZ-B)
Manual Transmissions:
16-teeth-wine (C0DZ-A)
17-teeth-white (C3DZ-C)
18-teeth-yellow (C0DD-B)
19-teeth-pink (C0DZ-B)
20-teeth-black (C1DZ-A)
21-teeth-red (C4OZ-A)
Auto Transmissions:
16-teeth-blue (D0AZ-A)
17-teeth-green (C7SZ-A)
18-teeth-gray (C7SZ-B)
19-teeth-tan (C7VY-A)
20-teeth-orange (C8SZ-B)
21-teeth-purple (D0OZ-B)
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Thread Starter
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Laughing Gas
Joined: Oct 2010
Posts: 997
Likes: 2
From: Rock Valley, IA
Thanks Gary. Hopefully one of the 5 gears that I ordered will make it read true. Any idea how to test the speedo to see if it is correct? Other than asking a cop to tag me with a radar gun.
FTE Legend
Joined: Jul 2010
Posts: 32,875
Likes: 48
From: Northeast, OK
Several ways. First, if you have an iPhone just download the free app called Fast. It uses the GPS system to get you w/in about .1 MPH.
If no iPhone, get on a road with mile markers or mile sections, and run a steady speed for X miles, noting how long it takes. Then, average the time by dividing the total # of seconds by the # of miles to get seconds per mile. Divide that into 3600 to get MPH. For instance, let's say you ran for 5 miles and it took 350 seconds. Divide 350 by 5 to get an average of 70 seconds/mile. Divide that into 3600 to get 51.4 MPH. The further you drive the better the resolution, but if you are pretty steady on the speed you can get it to work fairly well at one mile.
Or, have someone with another vehicle pace you.
If no iPhone, get on a road with mile markers or mile sections, and run a steady speed for X miles, noting how long it takes. Then, average the time by dividing the total # of seconds by the # of miles to get seconds per mile. Divide that into 3600 to get MPH. For instance, let's say you ran for 5 miles and it took 350 seconds. Divide 350 by 5 to get an average of 70 seconds/mile. Divide that into 3600 to get 51.4 MPH. The further you drive the better the resolution, but if you are pretty steady on the speed you can get it to work fairly well at one mile.
Or, have someone with another vehicle pace you.
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