That is indeed a black six tooth driven gear. With that you would need a 17 or 18 tooth driven gear. Appears you have a 21 tooth red driven gear so that will in fact read way slow if the red gear is in fact a 21 tooth.
T5 Identification Advice Needed
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Your tach seems to be right on. Those marks are in 250 RPM increments, so it’s reading about 800 RPM.Ok, got the tire diameter from circumference using a rope:
I think we can call that 79”
With that, we do 79/pi to get a diameter of
25.146”.
Also used my timing light to check RPM at idle, engine settled to about 850 RPM, and here’s what my tach looked like:
I’d say the factory tach reads about 100 RPM fast.
I’m going to list what we know right now, because I feel like I’m going crazy trying to figure this out:
Tire height = 25.146”
Diff gear = 3.73
Adjusted RPM at GPS rec’d 60 MPH in 5th gear = 2700
According to Motor Trend, the formula for speed from RPM and gear ratios is as follows:
(RPM * Tire Dia.)/(Trans Rat * Rear End Rat * 336)
So our formula would be 60 = (2700 * 25.146)/(X * 3.73 * 336)
67,894.2/1,253.28X = 60
54.173/X = 60
54.173 = 60X
X = .90
So my 5th gear ratio should be .90:1
The only factory T-5 from Ford that even comes close is the one from the 86 mustang 2.3 at .85:1. If this is the correct transmission, my guess is the VIN indicates it was made in 85 for the 86 model year.
Either that or somebody in the past rebuilt it with a weird custom gear ratio.
I’ll try to get the ratios for the other gears and see if there’s a pattern to follow that might line up with a factory transmission.
Bill
Ok, I scrubbed the stamping with a wire brush and here’s the result:
I can make out FF132202
Which means the trans came from a car made in Dearborn (a mustang) in 1985 and that it was the 32,201st unit of that car to be made (1985 started at 100,001).
With that, we have a number of possible combinations, but here’s what I’ve come up with so far: 1FABP2???FF132202.
There aren’t any partial VIN decoders I could find apart from the one on NHTSA’s website, and even then it doesn’t tell me anything I don’t already know.
Any ideas on where to go from here? I could just start plugging in every possible combination and record the results, but there’s a lot.
Edit: I guess it doesn’t really matter since we know it’s an 85 mustang transmission, so we only have 3 options. Neither of them make sense with the numbers I’m seeing though, so I’m wondering if my tachometer is off?
| Here are all of the possible VINs, and the number of "records" for each from Aut0check: 1FABP26A7FF132202 - 0 records 1FABP26M4FF132202 - 0 records 1FABP27A9FF132202 - 0 records 1FABP27M6FF132202 - 0 records 1FABP28A0FF132202 - 0 records 1FABP28M8FF132202 - 28 records 1FABP28T9FF132202 - 0 records The trans is from a 1985 5.0L hatchback |
Ok, that’s good to know at least.
And here I was trying to use NHTSA to look up partial VINs and getting nowhere. Thank you for your work, sir.
I think my problem then is the transmission was likely rebuilt at some point using the wrong parts. That’s the only reason I can think of for my weird gear ratios and the fact that the input shaft is too small.
What all this boils down to is: I need a new transmission. Maybe not right away, but sometime soon.
You were close. You just needed to know all of the possible bodies and engines (that could have a manual trans).
2-door sedan (coupe) = P26
2-door convertible = P27
3-door sedan (hatchback) = P28
The 3.8L had an automatic only. So that left the turbo and non-turbo 2.3L and 5.0L.
2.3L (LX) = A
5.0L (LX & GT) = M
2.3T (SVO) = T
So possible body & engine combos are ...
P26A
P26M
P27A
P27M
P28A
P28M
P28T
Then you can use the VIN check digit calculator at NHTSA. I made one using Excel so I used that.
Yeah, all I knew was that the SVO was hatch only, so I appreciate the detective work.
The clutch slipped a little bit pulling out of a parking lot today catching up with traffic, so I think that’s starting to go. As long as I don’t put my foot in it too hard it seems to be ok for now.
Which brings me to another question, I’m hoping to make somewhere in the realm of 350-400hp and around the same amount of torque sometime in the probably distant future. The strongest T-5s I’m seeing are rated for 330lbft.
The general opinion I’m seeing is “if you have a T-5, use it,” but since I’m going to replace it anyway, would it make more sense to spend a bit more and just get a TKX rather than a rebuilt T-5?
yes... Remember you need a new bellhousing, new clutch disc ( your getting a new clutch so....) new driveline input shaft and probably a new driveline . ( different length) for a TKX
And there are different ratio TKX transmissions... You can look them up on the Tremec website under.... Tremec.com... go to aftermarket.... click on products, click on TKX,..... click on specifications......
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I am at 450ish fwhp and 370ish rwhp and my T5 is doing fine. The question you need to ask is am I going to be able to plant the power at the tires. This is what breaks T5's or any transmission for that matter. My T5 has a couple of parts that help with the flex but nothing special.
In your case if you are going to buy a new transmission then the TKX would get my vote over a new T5. As Limp said you will need a few new parts but sounds like most of what you have will be replaced anyhow.
In your case if you are going to buy a new transmission then the TKX would get my vote over a new T5. As Limp said you will need a few new parts but sounds like most of what you have will be replaced anyhow.
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