4r100 help/ weird shifting

[littleredstroker]

Have a buddy who had a trans built by a shop here locally, about a year ago. Said just a few weeks ago it started shifting hard, said it felt like something was rear ending him every shift.10k miles on the fluid. My first thought was valve body. But why would it just now be starting?

Has edge cts for monitors, sometimes uses the tow tune, shifts the same with or without it on. Any ideas ?? They told him he needs a new pcm ...

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[littleredstroker]

Ain't nobody got time fo dis ?

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[littleredstroker]

Top

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[Jennifer@Dieselsite]

Did he recently change his tuning?
Tuners turn up line pressure to give firmer shifts.

However, if he hasn't changed any of his tuning or anything recently since the problem started, it is possible the VB is getting dirty and is getting clogged.

 

[littleredstroker]

Did he recently change his tuning?
Tuners turn up line pressure to give firmer shifts.

However, if he hasn't changed any of his tuning or anything recently since the problem started, it is possible the VB is getting dirty and is getting clogged.

That must be it. There has been no changes.

sent while staring at a windowed block

 

[Mark Kovalsky]

A clogged valve body? I've never seen that. How would it happen?

The ONLY way to find out what's wrong is to get the codes read. That will tell where to start looking for the problem. Without the codes all I can do is list everything in the truck and he can replace all of them and hope it's fixed.

 

[littleredstroker]

A clogged valve body? I've never seen that. How would it happen?

The ONLY way to find out what's wrong is to get the codes read. That will tell where to start looking for the problem. Without the codes all I can do is list everything in the truck and he can replace all of them and hope it's fixed.

No codes except 603.

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[Jennifer@Dieselsite]

Clogged was my personal word choice because I'm bad at transmission talk

A more appropriate word would perhaps be sticking.

 

[Mark Kovalsky]

A symptom of almost every code is hard shifts. When you only got a P0603 I question if the scan tool was capable of reading transmission codes. Many (most?) are not capable.

As for a sticking valve body, yes, that's possible, but if the shifts are hard on every shift you would need to have multiple valves stick at the same time. Possible, just not likely.

 

[Lethalthreat7.3]

I agree, need to make sure transmission codes can be read. With that said, it sounds like an issue with his VSS. Does the speedo bounce or jump around even just slightly? Verify that the wires aren't worn back by the left brake cable going to the sensor in the top of the diff.

 

[01REDSTROKER]

My dads 4r100 would lock up very hard and after about a day of that it wanted to start out in 2 gear. It had codes but I don't remember them. Installed a new vb and it was still doing it.
Some one said change out the pcm, so we did....fixed all the issues and that was two years ago.