Well, I rebuilt my 4L60e with 201,000 miles on it this summer, and when I reinstalled it last month, added to it a Circle D 3000 stall converter. Was driving it today, at about 80% throttle from a stop, and the tranny shifted at 5000 rpm or so. (Per HPTuners, the PCM thinks the tranny is seeing about 320 ft-pounds or so in this range, and I've got the PCM programmed for a 0.275 second shift from about there on up, but my NA engine doesn't get that much more than that. Get a real nice squirm in my Avalanche when hitting 2nd at WOT, or at least I used to.)

When the tranny hit second, I got a terrible shudder. Let off the gas, and when the engine got down to about idle speed, shudder went away, but would come back when I applied throttle. Pulled over, shut it off, and then restarted, hoping for a miracle with a PCM "reset". The reset did manage to clear my braking system idiot lights and the message to service the braking system. Truck idled fine, but got the terrible shudder when I gave it gas, with the gear selector in all forward gear positions. No shudder in reverse, but no movement either - acted like it was in neutral. I was on my way out of town - swapped vehicles with the wife to catch a flight - and she tells me that when the tow truck guy rolled the truck into our driveway there was a definite rattle coming from it.

Anybody out there care to speculate as to how much of a mess I'll find inside this thing???

 

you broke something.

 

http://www.youtube.com/watch?v=rY0WxgSXdEE&ob=av3e

 

You guys are a lot of help!

 

nothing we can really say. sounds like something in the trans broke which means it needs rebuilt.

Likely a busted planetary or sunshell. If you can fix it yourself it would help a lot. I know I want to learn how to do it at some point.

 

The obvious would be with no movement would be a damaged pump. If you have movement and an issue with the vibration, I would suspect either a bad shell, planet or some other internal issue. Best of luck getting it sorted out. Vince

 

I humbly suggest http://www.finishlinetrans.com/

Sorry to hear about what happened though, I've blown up 2 60e's so it's not just you, good luck!

 

Thanks Vince. I rebuilt this myself over the summer, and with the price of the upgraded parts I put in it, I quickly learned why your transmissions cost what they do. The nearing retirement engineer in me that doesn't do any real engineering any longer enjoyed the technical aspects of doing this thing myself, as well has me very curious as to what is broken. Will start pulling the tranny out this morning. Hope to by end of tomorrow have the thing opened up.

The vibration didn't occur when revving the engine in park to 4000 rpm. If it was a pump problem, would I get the vibration when revving in neutral/park as well as when in gear?

 

I'm thinking I've at least broken the tailshaft. Should have put in that damn expensive shaft!!!

 

You need to have a look at that sunshell and planets.. Sounds like you've probably got more issues inside.

The best way to learn is to get your hands in there!

Any reason you didn't just zero all your shift timing out? Is the valve body modded? It gets the shifts completed as fast as possible and saves a lot of undue wear.