4L60E no 3rd/4th gear

My hatred of the automatic transmission just intesified....

98 Jimmy 4x4 115k miles drove fine yesterday.

This morning it shifted odd and early into 4th gear. This was right out of the neighborhood, so first 4th gear use of the day. Manually went to 3rd and drove fine for 9 miles or so. Got to a faster road, shifted to 4th. Trans seemed to slip or no 4th. Shift to 3rd, no 3rd. 

Scream many, many foul words, slow to 30mph and shift to 2nd. Drives fine in 2nd.  Stop and check fluid, it's fine. Shut off and restart (to reboot PCM). 

1st-2nd ok, can be coaxed into 3rd but won't hold (slips). Drove last 6 miles to work in 2nd at 35mph. That made a lot of people mad....

Changed fluid and filter 15k ago. Everything looked good at the time.

Hope it's a switch/solenoid/something but no clue where to start. No check engine light.

Have I mentioned how much I hate automatics?

In reply to Gearheadotaku :

The 3-4 clutch pack slipping is a common issue and the root cause is often with the 3-4 apply piston (the seal ages and hardens with heat/time). How does the fluid currently look/smell? If the 3-4 clutch pack burned up, I would expect a noticeable odor and change in fluid color.

That sucks.  Definitely sounds like something in the black magic innards went kablooey (technical term).

I hope you have a spare vehicle while that one is down.

3-4 clutch pack is the same on a 700r4/4L6x-e, so it's natural to lose both.  Drop it at a transmission shop and bend over or find a used one and lay on your back in February to change it and hope it's good.  
 

OR find a manual trans s10 and swap it

Luckily I do have another car to drive, just would rather not take it out in the salt.

Yeah....

We have had a pretty bad issue with chevy autos crapping out around 80-100k on the company 1500's. Had another one a few weeks ago. Out of the last 6 or so chevy 1500's which mainly get highway miles, there has been  prob 4 auto failures before 100k. Some have had 2 trans rebuilds before 150k miles.  The fords tend to get close to 200k miles and are sold off before any trans issues. 
 

and my personal nissan truck with auto started pooping out this week with less than 80k miles. Id much rather have a manual. 

Sun shell likes to strip the splines giving you only manual first and second plus reverse. Either way, whether the shell or clutch pack, it's internal.

Ok it's lunch break. Went out and looked at the fluid again (now that I have proper daylight) confirm it's red ,full and not burnt or stinky. 

Drove the truck and it will not upshift to 3rd, just stays in 2nd. 1st and reverse are good. No check engine light.

Probably still screwed eh?

Yup

In reply to Patrick :

What was the thing that broke on the 700r4 in my Suburban that I called you about from the side of the interstate? I think the symptoms were similar & the repair wasn't too expensive.

My 4L60e went nuts, not exactly the same as this example and it was the ignition switch causing it.

No 1st. 2-3 manually only, no 4th.

In reply to Gearheadotaku :

To clarify, it will not upshift to third or it shifts but then the engine rpm increases without an increase in road speed?

If it doesn't even try to shift to third it likely isn't the 3-4 clutch pack (plus the good fluid quality reinforces that it isn't the 3-4 clutch pack).

As Ranger50 mentions, a broken sun shell will also mean no 3-4 gears but I I would expect it to try to shift and engine rpm to increase in that case as well.

My old Suburban acted totally wonky when the TPS went partly out.  The truck drove fine until you got more than 1/2 throttle, at which point it ceased pulling and acted like the trans was slipping.  Turns out it was just a bad signal messing with the "E" in 4L60E.

But it went into all the gears just fine.

Since every shop will just sell you a new used transmission, you might as well just drive it until it totally craps out.

In reply to Pete Gossett :

Yours was stripped governor gear teeth and a stuck throttle valve in the valve body.  Diagnosing both of those from 500 miles away via phone is probably one of my most insane accomplishments

In reply to Patrick :

That's why you're the GM trans whisperer!

Automatic transmissions are voodoo......electronically controlled automatics are just weirder voodoo.

 Drove it with a scan tool hooked up. We could force it into each gear with the scanner, 3rd and 4th slipped alot.

Found a used trans. It was remaned by Jasper at some point in its life so hopefully it will be OK. Its cheaper and faster than a proper 5-speed conversion at this point. I do feel bad about not playing my part in save the manuals though...

Trans is out, at least now I can put in that rear main seal.  The guys at work are doing the heavy lifting for me.  Feel very, very lucky. Not sure what the bill will be when they are done! Worth it whatever it is plus buying a good lunch.

Sounds like a clutch pack to me.  If they pull the clutches and they look good, check for hairline fractures around where the input shaft goes into the input drum.  Not a common problem, but 4L60E/700r4 are the only ones that stealth you into thinking you're crazy.

Unlikely solenoids.  Slight possibility of a galled piston/bore in the valve body, but that usually shows up as really hard shifts.

Another common thing with many GM transmissions is the separator plate for the valve body.  One or more check balls like to become lodged in it or go right through it after so many peens (don't google that phrase).

Might also be good practice (check prices) to replace the internal wiring harness.  Years of heat and hydrocarbons take their toll.  One thing I always do before I yank a 4L60E is to use a scan tool to check what the ECM thinks the transmission temperature is.  If you get something crazy like -256F, the temp sensor (which is inline in the internal harness) has failed and you'll get really weird shifts

Did the trans make a whine for a while before failure  that varied with road speed? Cause my 4l60e has started to whine....

 No whine or odd noises. It was a cold morning when it happened, about 15 degrees F.

 Not going to open up the trans to see what happened inside, needs to go back as a core.

In reply to Dusterbd13-michael :

Most whines are pump related or low fluid levels.