4L60E Level 73 Wizards please help!

[JCzNova]

Looking for direction from the automatic transmission gurus for a troubleshooting list for a car I am going to look at Friday.

'93, 60k on rebuilt engine, says 233k on the body, didn't get an answer yet on the trans mileage.

Information from seller:
-Was driving fine, then changed the filter and gasket. Then shifted up and back to first and would not shift out of first again.

Just looking for some ideas of things to check while I am searching for a new trans. Obviously if it is pissing fluid, I will see if there was anything left on the stick, and it will come out anyway. Maybe that low of fluid kept it from shifting?


Ok, gurus bring on the ideas!

And thank you everyone in advance.

[Sahara54]

Cahall

[CPT]

a '93 doesn't have a 4l60E. It has a 4L60. The 4L60 closely resembled the 700R4, as it is hydraulically shifted instead of electronically shifted like a 4L60E. Since it still uses a gevernor and a throttle valve cable, you have a couple possibilities for the "no upshift". Governor gear could be stripped or broken off. Governor valve could be stuck. Throttle valve in valve body could be stuck.
As for the leaking pump, The teflon pump bushings GM used are notorious for falling out of the pump. When they "walk", they will cause a front seal leak. We ALWAYS replace them with the older style 700R4 pump bushings to prevent any possibility of a repeated failure.

Frank

[JCzNova]

Cahall

Thanks Frank, I am just starting my knowledge base on the LT1 F-bodies. I will do some googling on checking those items on a 4L60 and get a game plan together. It would be great if I didn't have to buy another transmission, and the PO didn't do any troubleshooting before selling it.

I am hoping for the best, but think I have negotiated a decent price even if I have to replace the entire trans.

[CPT]

If there's anything else I can help with, let me know.

Frank

[JCzNova]

A quick update as I got a more detailed story on the car. PO was doing things, and went to change the trans filter last. Did the change, went down the road and it shifted up. He said it then downshifted itself back to 1st gear, and wouldn't upshift again.

It was great news to me as I was happy with our agreed price wagering on worse case of buying another transmission.

Starting with this:
-Didn't have the filter seated and now is sitting in the bottom of the pan. Maybe he didn't get the old seal out with the filter and both are in there.

[CPT]

Unless the pan is collapsed, it won't restrict flow. We have them come in with 2 filter seals in them all the time. There's enough room in the pump for them. I can't see either one of those being a possibility. It's more likely that it's a throttle valve sticking.

Frank

[JCzNova]

Unless the pan is collapsed, it won't restrict flow. We have them come in with 2 filter seals in them all the time. There's enough room in the pump for them. I can't see either one of those being a possibility. It's more likely that it's a throttle valve sticking.

Frank

Is that an item I can tackle without pulling the trans? I need to do some 700R4 research, that's for sure.

[CPT]

Yes. The Throttle valve (TV valve) can be removed, just by dropping the valve body. We install a low tension return spring in the valve to help prevent it from getting stuck, but they don't have them in factory transmissions. With the valve body off, it's a matter of pulling out 2 roll pins to get the valve out. I would suggest installing a return spring while you're there. Let's not forget thare are still other options. Governor valves do get stuck on these, and the plastic governor gears break or "apple core". The governor is accessible under the large round cap near the tail housing on the drivers side of the transmission. Do you actually have the car in your possession yet?

Frank

[JCzNova]

Yes. The Throttle valve (TV valve) can be removed, just by dropping the valve body. We install a low tension return spring in the valve to help prevent it from getting stuck, but they don't have them in factory transmissions. With the valve body off, it's a matter of pulling out 2 roll pins to get the valve out. I would suggest installing a return spring while you're there. Let's not forget thare are still other options. Governor valves do get stuck on these, and the plastic governor gears break or "apple core". The governor is accessible under the large round cap near the tail housing on the drivers side of the transmission. Do you actually have the car in your possession yet?

Frank

Yes, picked it up yesterday. Just parked it at my work shop for the weekend and not going to get to it until Monday while everyone is off and out of the way. If you could give me a list of what order you would check things it would be great.

Watched a few YouTube videos and those are hit and miss with GOOD info. The fact that it happened as soon as he dropped the pan and changed the filter/gasket is what has me really hopeful.

[CPT]

When you get a chance, try this first. Lift the hood and locate where your TV cable attaches to your throttle body. Start the car. unhook the TV cable from the throttle body and pull in out rapidly and let it snap back. Try this a few times. This floods the TV circuit with fluid and can sometimes unstick a TV valve.

Frank

[JCzNova]

When you get a chance, try this first. Lift the hood and locate where your TV cable attaches to your throttle body. Start the car. unhook the TV cable from the throttle body and pull in out rapidly and let it snap back. Try this a few times. This floods the TV circuit with fluid and can sometimes unstick a TV valve.

Frank

I will put that at the top of the list. Should have some feedback on Monday. If the rain keeps me at home today.

[CPT]

OK... Let's try that first and we'll go from there. The path of lease resistance is always best.

Frank

[JCzNova]

***UPDATE***

So, I got a few hours in on the car this morning.

-Checked the fluid. None on the stick.
-Started is and did the above mentioned TV Cable exercise.
-Dropped the pan, and there was about a 1/4" of fluid in it. Thought it was empty when I got all but two bolts out and nothing came pouring out.
-Filter was not in the pan. Only had only bushing/seal. Does not fit in the hole as tight as I remember by 60E fitting.
-Worked the Throttle Valve from the inside. Seems to move nice and freely. The cable does need a little adjustment, but I did not see any place to adjust it like the internet searches say. It is clipped into the bracket up top before the TB with no kind of slack adjuster. Nothing on the trans side of the cable either. Inside the case there is about 1/8" gap between the valve and the bracket that pushed it in.
-Closed it back up. Added 4 quarts of fluid.
-Took it down the road, and what do you know? It shifts up just fine. Just had the 100 or so yard parking lot next to my shop so I didn't get it wide open for long. Not enough distance to ride it out and see how it shifts at WOT and up in the rpm range.

However, that little bit of tinkering and it shifting now, is a cause for great celebration on my end ! ! !

[Blackbird96WS6]

Nice! Sounds like you may have just lucked out big time. Hope it stays strong once you get a chance to really test it all the way through the gears.