2000 K3500 transmission issues

[ChevroletTough]

 

Hey guys! merry Christmas. My gift this year? A head cold and now transmission issues with my 2000 k3500 7.4l 4x4 (reg cab long box) base model.

 

Issues just started last week. I noticed the transmission shifting hard from 1-2 randomly. 2-3 and 3-4 no issues at all. Takes a long time to shift from 1-2 as well and sometimes it’s fine and sometimes it’s sort of hard and sometimes the truck jumps it’s so hard.

 

Fluid looks good.

 

I think it might be slipping in 4th from OD as well at highway cruising speeds when I let off.

 

I’m not a transmission guy at all and have done a little reading. Plan to check the code (has an o2 code right now that I’m aware and need to replace).

 

Rpms seem to been good still.

 

Has 117,xxx miles on it.

 

I’m not thinking the 1-2 shift solenoid but I don’t know what a failing ones symptoms would be. Gosh that would be an easy fix!

 

Thanks in advance!

 

 

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[m&jtrans]

Sounds like the ball bearings in the valve body are sticking. My 1st recommendation is drain the fluid and filter and refill it with a synthetic atf (red line)
No matter what do not use Royal Purple!!!
If the valve body is the problem. You can pick up a new one and put it in at the same time as the fluid n filter change. Its pretty easy to change.
Oh I definitely suggest that you drain the torque converter fluid also. It should have a plug in it drain it out usually holds about 3 qts us the trans fluid.

The Blue Mule

[ChevroletTough]

Thankyou sir. Fluid was low after checking again and I topped it off. Going to take it out for a spin again. Planned to do a pan drop and filter change. Possibly 1-2 (ab) shift solenoid too.


Merry Christmas and thanks for responding


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[ChevroletTough]

Def seems like it shifts better until it warms up. I’m not sure i want to piss away $86 for a filter, gasket, fluid and the 1-2 shift solenoid. That’s me doing it myself. On the other hand if that fixes it, that saved me money.

 

No ecu codes for transmission on my scanner.

 

 

Is the valve body hard to do? Just a bunch of bolts and a gasket? Anything else? A video showed a tube needing to be removed.

 

 A few guys said the TPS sensor is the first thing to change when only 1-2 is hard. Going to order one as well.

 

 

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[ChevroletTough]

I found this and it sure makes it look not hard. Problem is that a person should really remove the entire tranny to do the balls, right?

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[davester]

You don't have to, the balls will stay in place if you are careful when installing the valve body.  You may wish to put a bit of transmission assembly lube under each ball to hold them in place.

[ChevroletTough]

Thanks. So after further reading it sounds like the TPS sensor can affect 1-2 shifting. I replaced it and cleaned the NASTY throttle body. Starts, runs, and shifts better. I may still drop the pan and change the fluid/filter, and 1-2 shift solenoid


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[OZRY83]

Well if you have 117,000 miles on it and you've never changed filter on trans I would do that no matter what.

[ChevroletTough]

Man it's tight up in there. Trying to locate both speed (VSS) sensors on the 4l80e, I think I have them located, 8mm bolt? Man that's tiny.

 

This is a 4x4, is one of the speed (VSS) sensors on the transfer case?

 

I really think one of the speed sensors (VSS) is causing my hard 1-2 shifting as the speedo doesn't work until over 10mph. Around 50-65 it will jump all over as well.

 

I've searched the internet and think they are both on the drivers side of the transmission, not too far apart from eachother?

 

Thanks again guy!

[ChevroletTough]

While I was looking, I found a sensor on the tailshaft, appears to be this guy:

 

https://www.amazon.com/gp/product/B000EQQWHK/ref=crt_ewc_img_huc_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

 

That part # shows up as the HD option for my truck as well. I already got the bolt out for the sensor and put a little anti sieze on it and put it back in. I didn't remove the sensor itself to confirm but it sure looks right. I'll probably order it.

 

As for the other two sensors, they are both on the side of the transmission? One by the gear shift lever and the other a 4-5" back farther, correct?:

 

2 of part # 24203876 per acdelco lookup by VIN (one for intput and one for output)

https://www.amazon.com/gp/product/B0013FTZUC/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

 

 

 

 

 

 

[ChevroletTough]

Well if you have 117,000 miles on it and you've never changed filter on trans I would do that no matter what.

I have owned it for a few thousand miles thus far. Will drop pan and change fluid/filter for sure.


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[davester]

Yes, one of the VSS's is near the front of the 4l80e, the other is either at the rear of the 4l80e or the rear of the transfer case if you have a 4x4.  They are the same sensors.  Examine the VSS you take out of the transfer case, look for bits of metal on it, or if it appears to have been rubbing on the tone ring.

[ChevroletTough]

Yes, one of the VSS's is near the front of the 4l80e, the other is either at the rear of the 4l80e or the rear of the transfer case if you have a 4x4.  They are the same sensors.  Examine the VSS you take out of the transfer case, look for bits of metal on it, or if it appears to have been rubbing on the tone ring.

Thanks I planned to check the current sensor but have new ones since they are so cheap. I’ll try to take a look tonight.

Thanks everyone for your continued information!


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[ChevroletTough]

The 2 rusted brackets with sensors are the speed sensors (see pic 1 and 2). They appear to be the same sensor, and man are they on there. I soaked both in pb blaster and will let them sit. I may need to get my mini torch in there and heat them up.

Sensor 1 farthest forward, above the neutral switch box ( 24203876 )


Sensor 2 by gear shift lever, right where the spot of the flashlight is (same as above 24203876 )



Sensor on back of transfer case, different style (213-204):



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[ChevroletTough]

Looking at it closer, the second one doesn't look like it has a harness plug into it at all, just the first one??