[thebeavis]

I have an 83 blazer 4x4 with a 97 vortec 350 and a 99 4l60e. Sometimes it doesn't want to shift to 4th gear unless i take my foot off the gas. Is it a simple fix or in need of a rebuild? I drove it for 8 years with this trans before having any issues.

 

[Rhotpursuit]

What are you using to control shifts?

 

[thebeavis]

The factory pcm that came with the engine.

 

[Tranzman]

The factory pcm that came with the engine.

Can you look at shift commands? When it doesn't shift, is it still getting the command for 4th?

 

[thebeavis]

I have a scan tool with live data, but i'm not sure if it covers many of the transmission parameters. Can you point me in a direction of what to look for?

 

[Tranzman]

Most Auto-zone type scan tools are great at engine codes and engine data, but don't have the capabilities to look at transmission data.
Chances are you will need a better than average scan tool. Most scanners that offer bi-directional capabilities will do it. These are Repair shop level tools.
If you don't have one. Maybe a friend with one can help or most Transmission shops still scan for free in hopes you will have them do the work or charge a small Diagnosis fee. That is usually 1/2 hr labor.
I had a friend that i built a 4L60E for and about a year later it cut a seal in the 4th servo & lost 4th. It still had to come out to be fixed, it burned the band bad enough it wouldn't hold 4th. I'm surprised his little 4 banger had enough HP to make it slip.

 

[gavin0]

I have an 83 blazer 4x4 with a 97 vortec 350 and a 99 4l60e. Sometimes it doesn't want to shift to 4th gear unless i take my foot off the gas. Is it a simple fix or in need of a rebuild? I drove it for 8 years with this trans before having any issues.

Sounds like an issue I had when I first bought my S10. Almost exactly like it. Would not shift into 4th unless you had the rpm right. My issue was and still is the transmission pump. It is going out so I overfilled the transmission fluid and it started shifting right.