test a transmission out of the car?

-
M

Mopar87

Well-Known Member
Joined
Jun 26, 2018
Messages
113
Reaction score
47
Location
Lewiston,Id
My 73 scamp came with a spare 904 transmission in the trunk.Other than helping the rear springs go negative I can't tell if its good or bad,Is there anyway to test it for proper function in my garage?
 
Nope. Pull the input shaft in and out and see if it's looser than about .070. You could remove the pan and see if there's much residue in it. Remove the valve body and air check the clutch drums and servos, take apart the valve body and check for sticking valves, pull the pump and check the front drums, remove the tail housing and check the governor..
 
Honestly if your going to air check it just wait and rebuild it. Why make a mess of the garage / space because it can air check good but still be at the end of its life span.
Just my humble opinion.
 
lol
if the pan and vb are off, then in about 5 more minutes, the rest of the pieces are ker-splat on the table. And in another 5 minutes the sub-assemblies are ker-splatted too.
Then it's off to the phone to order a TF-2 kit,etc, a 2800TC,a governor kit, and a cooler.
A few C-notes later,Shazzam! you got yourself real nice street trans.
Next? 3.91s
 
Last edited:
Dont get me wrong I dont plan on spending ANY money on it.My scamp has a 904 already under it, and because I got it with no driveshaft it leaked all of its fluid on the ground when I went to load/unload it.Judging the by the color of the fluid its original transmission is probally "OK".Space is tight so I was trying to figure out if the spare is worth keeping. I'm just gonna get the scamp up and running on an old truck 318 and the automatic thats in there.Eventual plan is a 5.2 magnum engine swap complete with fuel injection and a 5 speed manual transmission, AND 3.91 or 4.11 rear gears.

I saw a video on Youtube where they hooked a drill to the input shaft and spun it while shifting the transmission through the gears and watched the tailshaft for movement.Is that possible to do or would it damage the transmission?
 
Mopar87 said:
I saw a video on Youtube where they hooked a drill to the input shaft and spun it while shifting the transmission through the gears and watched the tailshaft for movement.Is that possible to do or would it damage the transmission?
Click to expand...

That must have been a HUGH drill for the chuck to open that far. Spinning the input shaft will do nothing, except tell if components are "welded" together. Spining the input shaft will not turn the front pump, and without oil pressure, nothing is going to engage.
 
I have some extra space in the bed of my truck and am only 4 hours away.
Lol
 
Mopar87 said:
I saw a video on Youtube where they hooked a drill to the input shaft and spun it while shifting the transmission through the gears and watched the tailshaft for movement.Is that possible to do or would it damage the transmission?
Click to expand...

If someone took the time to fabricate a proper pump-drive to go with that, and looped the oil lines, then yes it could be done. But it would only tell you that the circuits are working...or not. The clutches etc, could still be almost trash, and as soon as you put a load on the output-shaft, they could slip. But as already said; it would take a heck of a drill,not a fractional horsepower, and generally a drill that big is geared pretty slow. To be useful, I think you would need a brake on the back, and probably a 20hp electric motor, and a fluid coupling.
I worked at a transmission overhauling place in the 80s, and we had a 302Ford engine as a power unit. That thing ran almost from morning to night, testing every P-car and light-truck transmission the guys on the auto-line built. We had extremely few warranties. I think there were 4 or 5 guys on that line. I was the guy cramming out standards, all by myself, until they found out I could do more. Then they fired bigger and bigger stuff at me, and hired two guys to do what I had been doing. During my stay there, they doubled the business twice in about 4years, then built a huge complex; at which I only stayed about a year and a half. My favorite transmissions to build were RoadRangers which came in highway tractors; they gave me quite a workout. In between, I built rear-ends, alongside another guy.They moved me along fairly quickly after I became proficient at reading and adjusting patterns. All in all, that was a fun part of my life. Eventually I was building power-shifts and such, transmissions almost big enough to stand inside. That was fun,
and then I quit. It was time to make babies, and get out of the big city. That was 83/84 and our capitol was becoming a dangerous place to be. Sometimes I miss that line of work. And sometimes I miss the constant roar of that mighty test-mule 302.
 
"don't plan on spending any money"...does not compute. It's funny how people go to school for 13 years because it's free, don't learn many usable skills, then in RL are adverse to spending a dime to educate themselves on a topic that they're interested in.
 
Pan contents is about the only way to get an idea on anything without disassembling the trans at all.
 
I dont plan on spending money on the 904 because I despise automatics and the only valid use for one is if you have missing or disfunctional limbs.They take so much fun and joy out of driving that every car is boring to drive unless it has stupid amounts of power.There is fundamentally no difference in driving my 93 v8 dakota with an autotragic and my 2005 dodge grand caravan.Both are appliances, although one sounds alot better and accelerates faster.Neither of them compare to my 84 Nissan 300ZX turbo 5 speed or my 310 hp/686 lb-ft at the rear wheels 94 Dodge ram 2500 CTD with a 5 speed.With the 904 I'm just interested in seeing if it works to decide if I should keep it or sell it.
 
Mopar87 said:
I dont plan on spending money on the 904 because I despise automatics and the only valid use for one is if you have missing or disfunctional limbs.They take so much fun and joy out of driving that every car is boring to drive unless it has stupid amounts of power.There is fundamentally no difference in driving my 93 v8 dakota with an autotragic and my 2005 dodge grand caravan.Both are appliances, although one sounds alot better and accelerates faster.Neither of them compare to my 84 Nissan 300ZX turbo 5 speed or my 310 hp/686 lb-ft at the rear wheels 94 Dodge ram 2500 CTD with a 5 speed.With the 904 I'm just interested in seeing if it works to decide if I should keep it or sell it.
Click to expand...

Says the guy who hasn't yet gotten tired of shifting all the time.:D
About the only honest way of selling it without knowing anything specific is to sell it as a core. (maybe $125-$150)
 
I love automatics; I eat, drink, and sleep automatic transmissions. They can be programmed to react faster than the human mind and deliver what you need before you even know you need it.
 
If it's in your way, just drop out the guts, paint it red white and blue and mount it on a post in front of your house disguised as a mailbox.
 
CudaFactHackJob said:
I love automatics; I eat, drink, and sleep automatic transmissions. They can be programmed to react faster than the human mind and deliver what you need before you even know you need it.
Click to expand...

Apparently, the only driving you do is on the dragstrip.I have never seen a hydraulic controlled automatic ever leave a stop light in 1st unless its told to do so,I have never seen an automatic downshift for an upcoming low speed turn.I have never seen an automatic stay in the right gear for driving in snow unless its told.Automatics have alot of "lag" between when you press the throttle and when the car actually moves.Not a problem on the dragstrip but when you need extra power in a turn to get pointed the correct way its a big problem,its also a big problem when in town some moron is about to crash into your car and you need more power RIGHT GOD DAMN NOW to avoid them.An automatic can only react to situations, it can never predict them.It is ALWAYS faster to preempt something than to react to it. The only thing automatics are good at is allowing the driver to be more distracted and complacent. If everyone drove a manual transmission most driving problems today could be solved.It is damn near impossible to text while driving in a manual vehicle, same with eating,or all of the other countless dumbfawk distracted driving people do instead of actually driving.A manual teaches you to be a better driver because shifting alot in stop and go traffic sucks. Instead of rushing forward and then slamming on your brakes then rushing forward,etc, a manual teaches you to just roll through at an average speed.Which also happens to ease congestion because everytime someone brakes heavily you can see a "wave" of brakelights that will continue long after you have left.
 
Last edited:
Your automatics never start in first; automatically? I can't allow myself to believe those words. I have programmed automatics to downshift upon decelleration, but the factory doesn't. My trans can downshift faster than humanly possible. So...have you dropped the valve body yet? Cuz then I'll tell ya how to remove the pump...BUT CHECK THE END PLAY FIRST.
 
OP yur livin' in a bubble.
But I agree, you have to tell the trans when to shift......... same as a stick.
Thing is; with a re-programmed 904, you have three ways to accomplish the upshifts, and two ways to downshift.
And once you get it all set-up, you can concentrate on driving.
 
Last edited:
You must log in or register to reply here.
-

Back
Top