1rst to 2nd shift have always seemed lazy even after a BTS valve body install a few years ago.

Yesterday it wouldn’t shift to 2nd though the Interceptor gauge showed the computer thinking it had shifted.

i would speed up the truck in first enough to lift the throttle and it let it shift into 3rd.

If I pressed too hard on the throttle while in 3rd the trans would drop to 1rst though the gauge showed it downshifting to 2nd.

For a little while it would catch into 2nd. One time I held the throttle steady with the trans in 1rst, gauge showing 2nd, and the trans tried to catch 2nd a few times. It hasn’t caught 2nd since. All of this was during about 20 minuets of driving.

I pulled the main trans connector at it was dry, no fluid present. Cleaned the plug and connector, applied silicone grease, and reconnected it. No change in the shifting issue.

Drained about a half quart of fluid and saw no shiny pieces.

I can change either the valve body or solenoid pack myself. Which is the most likely culprit?

Thanks!

 

Neither. I suspect it's the intermediate one way clutch. Are there any codes stored in the computer?

 

Duplicate post

 

Time for a teardown.

Unfortunately this isn't a fix you will be able to do in-frame. Here's the broken part.

 

Just read them...

P1111

I cleared them and will look again after the drive home.

Is the one-way clutch something that can be addressed with the trans in the truck or does it need to be disassembled?

Edited to add: I didn’t see cleatus12r’s post before I responded...please disregard the question.

 

I’m rather sure this was upgraded to a 4100R unit along with a few other upgrades about 13,000 miles ago. I didn’t see any shavings, maybe the magnet snagged them.

Also, I have a magnifier filter in line.

Any other ways I can prove this to be, or not to be, the culprit?

Thanks

 

It's rare that too many metal pieces will find their way into the pan from this failure as the sprag "dog bones" don't usually explode; a few will break and the others cam-over.

A 4R100 has the same exact part unless it's a late 00 to early 01 (2001 model year).

 

Ok thanks. And just to confirm, losing only 2nd gear is the only symptom of this?

 

What is a 4R100R? I've never heard of that.

If the intermediate one way fails the only symptom is no second gear.

 

I pulled that number from an inaccurate orifice.


Thanks Mark and cleatus for your insight!

 

I have a line on a shop that is asking good questions rather than telling me to “just bring it here because you are too stupid to check a few things for your self”.

After the drive home I checked for codes with my AE and again there were none. Though I didn’t expect it to trigger a transmission code, a KOER test also yielded no codes.

Edited to delete the comment about the AE not seeing Solenoid 2 being signaled. The two solenoids signal correctly.

Likely not really helpful, but I noted that the gear selections yielded these readings on the AE;
1 .68v
2 1.37v
3 2.09v
N 2.83v
R 3.59v
P 4.40v

 

Just got let go from work so I have a little time to investigate before I take this into the shop.

The fluid is darker and there is more 'stuff' on the magnet than I was expecting after 13,000 miles, but there are no big pieces. I'll buton her back up and get it into the shop the second I land a job.

Thanks to everyone's input so far!

 

 

Final verdict:
2nd gear clutch and metal plates stacked backwards so the pressure plate was not the plate applying pressure. Clutch rings warped, worn through and one missing drive teeth.

Also, the two big flat gaskets were swapped top for bottom. These are on the plate that is almost the size of the pan itself.

 

Wow. Who the hell assembled that thing?

Pics of wasted clutches and they were coned in the center?