Transmission Woes

[Tri91]

I've two transmission woes I need help resolving.

First, I'm not the first owner of any of my Hondas. I'd like a way to verify that the proper transmission is in the cars without/before dropping the transmission. The serial number is a no go as they are all SL3-5serial#. I've crawled under the cars and read the stamp on the transmission housing but I understand that is no guarantee of what is in the transmission. I've read numerous posting on several forums about counting the engine rotations required to rotate the tire once. I did that and the numbers I got are nowhere near what they should be. While there are many variations, they all say basically the same thing. Here is the one I followed for my test.

Transmission In Car
A. Jack up front driver’s side of car and place a jack stand under it. Shift the transmission into
reverse.
B. Take a paint pen or marker and place a reference mark at the 12 o’clock position on the
driver’s side tire and another mark at the 12 o’clock position on the crankshaft pulley. Using
a socket and ratchet on the crankshaft pulley bolt, rotate the engine counterclockwise and
count the number of revolutions that the cranshaft pulley makes in order to rotate the tire
exactly one complete turn. The number of revolutions will tell you which Final Drive you
have. (See Chart Below)
C.
12.25 Revolutions = 3.88:1 DX (or ZC)
12.75 Revolutions = 4.05:1 EX (also some 90-91 Civic Si)
13.40 Revolutions = 4.25:1 Si
Anything less than 12.25 Revolutions = HF (three different ratios were available in HF)

And here is my transmissions' info:
#1-DX - 6.2 x2= 12.4 PL3/A100 SL3-5#
#2-DX - 6.2 x2= 12.4 PL3/A100 SL3-5#
#3-SI - 6.8 x2= 13.6 PL3/9000 SL3-5#

Additionally, since what is left of the engine in the White DX didn't require any effort to spin, I put it into every gear and counted.
1st 6.4 x2= 12.8
2nd 3.7 x2= 7.4
3rd 2.4 x2= 4.8
4th 1.8 x2= 3.6
5th 1.5 x2= 3.0
R 6.2 x2= 12.4

I believe that what I've read is correct because when you multiple the transmission ratio by the final ratio you get the number of engine turns per 1 revolution of the tires. Yes??? No??? It sounds right,... Soldiering on:
transmission ratio X final ratio = engine revolutions
1st 3.250 X 3.880 = 12.610
2nd 1.894 X 3.880 = 7.349
3rd 1.259 X 3.880 = 4.885
4th 0.937 X 3.880 = 3.636
5th 0.771 X 3.880 = 2.991
DX R 3.153 X 3.880 = 12.234
SI R 3.277 X 4.250 = 13.400

Oddly, if you double my measured numbers you get close to the calculated numbers, certainly within the relm of my eyeballed measurements.

What am I missing?



Second, the other transmission woe is that the White DX's engine overheated to the point that a rod connecting a piston to the crankshaft bent, hit the bottom of the cylinder wall, and brought the engine to a very sudden stop. This happened long before I owned it, I've no idea what happened to the transmission at that point. Is spinning the engine over enough to get roughly 12 revolutions of the tire a valid way to test the transmission under no load? It spun nice and smooth in all gears so I'm thinking that it'd not be a waste of time and effort to put it into the SI.

[IsaacCarlson]

You need to jack up BOTH tires or only do a half turn on the tire.

[some_other_dave]

Yup. With an open differential (most cars have those), you need to spin one wheel twice to get one rotation of the ring gear. So double the numbers you think you "should" be getting, or chop your measurements in half.

-soD

[IsaacCarlson]

Originally Posted by some_other_dave

Yup. With an open differential (most cars have those), you need to spin one wheel twice to get one rotation of the ring gear. So double the numbers you think you "should" be getting, or chop your measurements in half.

-soD

Sorry, should be two revs...LOL You should get the idea now.

[Tri91]

Hmm,... Ok, so if I understand correctly, immobilizing one tire will cause the other one to spin exactly twice as fast. So my count of engine revolutions is indeed off by half since I only turned the tire around once. Therefore, I've got 2 DX & 1 SI transmissions like I'm supposed to have. Yeh! Thank you.

About the second problem, that car had to of been in towing range (say 50 miles) of the used car lot I found it on. The main roads in that range have speed limits between 45-70mph. So the engine was probably at about 3000 rpm and in 5th gear when the engine seized. There is no indication that the front slammed into the ground as would have happened had the tires seized as well. I figure that either the clutch slipped and/or the transmission gear(s) are cracked/broken. Guess, since I was able to spin it without jamming or anything with no load, I'll have to put it in a car for a loaded test. That will envolve draining the oil,... Easy enough to see if there is any metal bits at that point. Anybody have real world experience with transmissions that have been through an engine seize at speed? Did they survive to live on or were they done for?

[IsaacCarlson]

most times the tires just skid and you stop really fast. Tranny should be ok if it spins smoothly and there is no noise/clicking. The clutch probably took the shock. I'd give it a try.

[some_other_dave]

You can try putting it in each gear and spinning the output flange. If it turns smoothly through a number of rotations (ideally, a complete revolution of the gear set inside the trans) without Ugly Noises (TM) or binding or excess drag, it should be fine. If the car actually was at speed when the engine seized, the tires likely slid or the clutch slipped. I think the CV joints are weaker than the transmission internals, as well, so if anything downstream of the clutch broke it would have been those.

-soD