pretesting a transmission
- Thread starter Dan/Kzo
- Start date
d.j. moordigian
Well-known member
Dan,
I don't see any value, IF all the parts are reasonable good. I have welded gears
and " hand fitted " them, even a ring gear on a flywheel, for my low buck pals.
The shift tower is more problematic, I think, forks, shafts, stick, balls and springs
Dudley
I don't see any value, IF all the parts are reasonable good. I have welded gears
and " hand fitted " them, even a ring gear on a flywheel, for my low buck pals.
The shift tower is more problematic, I think, forks, shafts, stick, balls and springs
Dudley
Tom Endy
Well-known member
What you don't want to do is mount it in the car and before installing the rear end run the engine and try to test it out. Without the U-joint installed it will dump oil all over the place. And if you install the U-joint it will flail all over the place. What we did was take a U-joint apart and install only the front end piece for the test. The U-joint is what holds the bearing snug against the bearing stop.
Tom Endy
Tom Endy
Dave in MN
Well-known member
Dan/Kzo
I have done exactly what you describe a few times. I made an adapter to fit the stub of the input shaft that had a set screw in it to clamp down on it. I borrowed the tool to a friend and I do not recall getting it back. I'll check my work area and post a picture of it if I have it. I also made a second version of the tool that used a "nut" as the adapter with three set screws. It's a bit crude but it works....see attached pic's.
When I first did the testing, I checked 4 transmissions we had in our stock pile so the learning of the correct sound was a matter of trial and remembering what conditions caused a particular noise. We also had a newly rebuilt transmission to use as a base also. The test will tell you if used bearings have excessive play and with a little back-loading by grabbing the u-joint you can tell if the gears will howl also.
I use a cordless driver/drill with a torque clutch set rather low for safety.
Set your transmission on a pad of carpet to isolate the sound and go to it.
Realize that you may be introducing a slight misalignment to the input shaft if you don't hold the drill correctly and it will make a sound...you'll know what I am describing if you try it. We have run the tests dry and with oil. Both methods will point out a problem if one exists. My only concern is that you will not have the benefit of listening to multiple transmissions for a base to judge.
Good Day!
Dave in MN
I have done exactly what you describe a few times. I made an adapter to fit the stub of the input shaft that had a set screw in it to clamp down on it. I borrowed the tool to a friend and I do not recall getting it back. I'll check my work area and post a picture of it if I have it. I also made a second version of the tool that used a "nut" as the adapter with three set screws. It's a bit crude but it works....see attached pic's.
When I first did the testing, I checked 4 transmissions we had in our stock pile so the learning of the correct sound was a matter of trial and remembering what conditions caused a particular noise. We also had a newly rebuilt transmission to use as a base also. The test will tell you if used bearings have excessive play and with a little back-loading by grabbing the u-joint you can tell if the gears will howl also.
I use a cordless driver/drill with a torque clutch set rather low for safety.
Set your transmission on a pad of carpet to isolate the sound and go to it.
Realize that you may be introducing a slight misalignment to the input shaft if you don't hold the drill correctly and it will make a sound...you'll know what I am describing if you try it. We have run the tests dry and with oil. Both methods will point out a problem if one exists. My only concern is that you will not have the benefit of listening to multiple transmissions for a base to judge.
Good Day!
Dave in MN
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Tom Endy
Well-known member
I think you are going to find that spinning the transmission on a work bench is not going to tell you much. When I rebuild a transmission, I shift the gears into each position by hand and turn the input shaft to see if it works properly. This only tells you that you put it together correctly. What you really want to know is if the transission is quiet (or noisy) and does it not pop out of gear. The only true test is when it is installed in a car and is out on the road under a load. If you can climb a steep grade in second gear with the transmission not screaming at you and it does not pop out of gear, it passes the test.
Tom Endy
Tom Endy
Dave in MN
Well-known member
Tom, I agree that installed and fully loaded is the only true test of a transmission but have you tried the method I describe? It often will point out problems with components prior to installation in the car. Granted, it may take a control transmission or experience with previous tests to compare the sounds to and most people will not have that. For instance...I discovered a defective "almost new" bearing using this test. The bearing spun smoothly when held in hand and did not appear to have excessive wear. How this particular bearing would have performed in the car...I will never know. I replaced it with new, tested it on the bench and the noise was silenced. I guess my point here is: It has worked for me and I will continue to invest the 10 minutes or less it takes to run the test. Completing the test may have varying results for others.
Good Day,
Dave in MN
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I made a adapter out of a clutch plate. Married it to a v-belt pulley. Using a electric motor, I then can spin it up to about 1750 rpms. If the gears are going to whine, you will diffenently hear them. I use it on all my rebuilds. The club members also, and guys from other clubs ask me to use it. It will make less work by installing and then pulling it back out or just living with a whiney trans.
Tom Wesenberg
Well-known member
Do you use a bearing on the input shaft pilot to stabilize the shaft?