Chevybaby93

Watch "Silverado 1" on YouTube

Thats what my truck is doing. In drive it wont move. It lost power (transmission wise not engine) going about 50 down the road. Upon removing inspection covers when in drive both the flexplate and tc spin. Neither appears to have cracks that i can tell. Not to mechanically inclined with cars though. 2 strokes yes. Any ideas? Dropped pan and didnt see any metal in oil couldntget all the way off due to space though. Atf was really dark red looked black in bucket. Transmission had supposively been rebuilt about 6 months prior. Any ideas?

clinebarger

If you lost all ranges, It needs to be pulled out & gone through.

If you want us to make wild guesses, I guess broken pump.

Chevybaby93

Any disgnostic test i can do to check pump before removal. Still getting all tools and money ready to take it out so just trying to diagnose as much as i can in mean time. Before this happened truck was stuttering between 40 and 60. Slight brake pressure would stop it. Which i read means a torque converter issue since brake switch disables it. The noise originally made me think tc/flexplate but i see nothing wrong with the just looking through inspection plate. Read something aboit coolant lines to test pressure. Would that help a diagnosis?

bbond105

It sounds like the fluid is burnt, with it being a dark red to black. To test the pump you could remove one of the trans lines from the radiator and start the engine. If fluid comes out fast it is pumping. The best way is to hook a pressure gauge up to it. It sounds as if the trans is beyond a minor in vehicle repair and is in need of a complete rebuild.

Chevybaby93

What would be cause of fluid burning? And was the surginf and complete failure connected or seperate problrms in your oppinion? Ok will try that. Guess i will need to put fluid back in to do this test as i already drained most of it looking for metal? And yes i know the trans will need removal. Thatd what i ment by saving money and trying to get as much diagnosed and get a better idea earlier so i know what to expect. Have to get truck leveled and lifted safelt on dirt. So have to buy jack stands and plywood and specialty tools to reach certain bolts to remove trans.

Chevybaby93

Sorry for double post. Im looking for a theory i guess. Like torque converter was causing surging and that failing ruined the pump and caused burnt fluid. Something along those lines. Just a guess i know noone can really know without me pulling it and showing detailed pics and even then still a theory

clinebarger

You can remove the cooler lines & check for flow, Or install a pressure gauge at the line pressure tap above the shift shaft.

The converter clutch shudder is most likely leaks in the TCC/PWM apply circuits that are not addressed in most halfassed rebuilds.

Chevybaby93

Okay thanks for that information. I bought the truck and hsd it about 2 months. It was raining one day and i did a little burnout through a puddle (if you call it a burnout lol) and about a mile later i heard a noise like scrubbing. Could feel it in gas pedal. Then about a month later stuttering started and noise went away. Then a month later rpms jumped as truck lost load (transmission) and vroom vroom to side of road. I wouldnt say i abused the truck. Maybe 5 full throttle pulls from 0 in its life. Rest where rolling


Also any best guess on clicking noise? That happened when truck broke down. So whatever fhat noise is is why ig won't move. It seems like i have more than one problem. This caused this which caused this which resulted in this. Want to make sure when i fix it i fix everything. Also how hard is it to replace a pump? I know i couldnt rebuild a trans but is the pump itself that hard?

bbond105

In most cases the pump is good. I would guess that the forward sprag broke or the 3-4 clutches are worn out. The burnt fluid is from brunt clutches.

lq4headache

I would say I would have agree if the fluid is that bad it's gota come out ....if ur going to keep it rebuild it a 10$ fix now turns into a 1200$ fix later do it ones

Chevybaby93

Okay. Would the forward sprag cause truck not to movr in reverse or sny gear? Also the clicking in the front is right where the pump is. Burnt 3 and 4. It shifted fine between 3 and 4. And brake pedal switch stopped it from studdering. Im not a mechanic just asking questions. Also is there any way the tc or pump caused fluid to burn? I was getting a code for tranny slip. But never felt a slip besides the stutter of the tc enganging and disengaging rapidly. Going to test pumo. From what i read dropping pan only loses 5/15qts so should still be enough oil in to do check right? And its on bottom of radiator? And closer description of location

If pump is fine then it looks like new tranny.. (complete) so its best if pump is gone am i right? Difference between 600$ to fix and 2,000$
And about the 10$ now could cost 1200 later. I know this lesson very well. So i dont want to just replace whats broken. I wanr to find out why it broke.

clinebarger

The Forward Sprag & 3-4's will not cause loss of reverse.

Pump (break-up) failures are quite common on "Rebuilt" 4L60E's, "Jobber" pump kits from trans parts houses have Cast Pump Rings like 700R4's. Your 4L60E had really good Steel rings from the factory, But could have been replaced with Cast junk that can & will break & destroy the pump.

But, I'm still guessing!

mrvedit

The test for a broken forward sprag is to see if the car moves with the shifter in D1. If you can accelerate by manually shifting the gears, but the car in dead when starting in D4/OD, then the forward sprag is shot. As mentioned, a bad forward sprag will not affect reverse.

There are relatively few parts in common between forward and reverse. If you lose both, it is nearly always a pump failure, although it could also be a failed converter or broken input shaft. Finally it could be a broken output shaft; depending upon where it breaks you might not even have [Park].

BTW - Its great having relatively new member clinebarger chiming in here; he has 17+ years experience rebuilding transmissions and knows performance builds very well too.

Chevybaby93

First off i would like to thank everyone for taking there time to help thus far. Its very appreciated

1. How hard is it for an amatuer to change pump?

2. Does broken pump hurt rest of trans or is breakage (particles) concealed to one area. Also would failing pump cause burnt fluid?

3. Any link or description of whdrs cooler line is on radiator

clinebarger

1. Not hard at all.

2. Depends, But the damage/metal is usually localized to the pump. Not that I have ever taken the risk of just replacing the pump. Do your self a favor & completely go through the unit or have it done by a professional....You can thank me later.

The pump failure will not burn the fluid, But a slipping Converter Clutch damn sure will, Nothing shears ATF down better! When you pull the unit out, Check out the converter cover.....If it is discolored/Burnt paint, The TCC has been really hot. Let me know about this, It will need to be addressed during the rebuild.

3. The bottom cooler fitting at the trans is the "Cooler Out", Follow it to the radiator, That is the one you need to pull.

mrvedit

While removing the cooling line is the definitive way to check for a defective pump, there is a simple 95% accurate way too...

With engine off, check the ATF level on the trans dipstick.
Start the engine and check the ATF level again. With a working pump it should drop about 1" as the pump forces fluid into the converter and other parts. If the level stays the same, it is likely a bad pump.

Chevybaby93

Only thing is i dropped pan so ite 5 qts short. Woulf i need to refill for either method to work? Dipstick, cooler line. Or would one worknand one not

bbond105

You will need to add back around 4qts of fluid. Both ways should work.

Chevybaby93

Okay now im lost. Started truck and let run 5 minutes. Measured. About 3 inches. Turned off and washed truck. Probably an hour. Measured again. Exactly an inch gain. Around 4 inches. Got dextron/mercon fluid 1 gallon. So if not pump what else can cause loss of all gears and a clicking sound right by converter. Converter and flex plate are both spinning with truck on.

Sorry for long delay. Had to save some money. All money here forward is for truck

bbond105

A broken converter will make noise.