Lost 4th Gear; Code 28 and 58; 4L60E

[1500z71]

I was off, this trans has closer to 140-150K on it. It is a 4L60E, forgot to put that in the title.

Took it out again tonight and it ran through all four gears just fine like nothing had happened. TCC worked exactly like @PlayingWithTBI explained it. Check Engine didn't come on again until after about 20 minutes or so and came on with the same codes. I reset the battery and everything when I got home, so I will take it out again tomorrow and see how it shifts and if the same code gets thrown. The transmission fluid was full, it actually was a little bit past the hatch marks.

While I'm glad it had 4th tonight I'm afraid the problem still remains like you're thinking @1998_K1500_Sub. I've been in my last semester of school this past fall so it hasn't been driven much besides a few weekends every month until now that I'm home for good again and have been driving it more, but even during that time, every so often, it would hang in 3rd but eventually shift to 4th.

Would a fluid change and filter change help or only complicate things at this point?

 

[Erin]

1993 K1500 5.7

Hey guys, looking for a little direction here, as I haven’t been able to find anything with my combination of issues.

Last summer ‘21 my transmission overheated pulling a buddies big pontoon. Pulled over and let it cool, topped it off, ran fine again for a long time until now.

Went on an hour and a half long trip this weekend and completely lost fourth gear. It has been having issues getting there for a few weeks now but as of yesterday it’s completely gone. Was still able to get home and it walked through 1-3 seamlessly, but there is now a second or so lag between R and 1 sometimes, at least that day there was. My check engine light stays on most of the time for EGR, but I checked it as soon as I made it home and it threw Code 28 and 58. Pressure switch and temperature sensor (both transmission) I believe. Few things I’m wondering about -

Code 58:
My question is could running it with high RPMs (~3K) at highway speeds for so long cause it to throw a 58 by running much hotter without the 4th gear? Does it work like that? Or is it saying that the temp. sensor itself has failed?

Code 28:
Did the overheating last summer cause this sensor to fail? How common are failures like this after overhearing?

And then finally - I’ve never torn into a transmission, but I consider myself mechanically inclined. How hard of a job is it fixing these two issues? I’ve got a guy that can rebuild these trannys in a day, but I always like to at least look into myself first.

Or is this basically tell-tale that the tranny is on the way out after overheating this summer?

I feel your pain. I killed a transmission in my 94 towing a pontoon in O/D. Made me sick.

 

[1998_K1500_Sub]

Would a fluid change and filter change help or only complicate things at this point?

AB-so-LUTEly... particularly if you do it yourself. The primary benefit is it will give you a chance to assess the condition of the transmission. If you haven't dropped a trans pan yet, then ask for tips, here. Moving on...

First, I would pull the stick at look at the oil carefully. If it looks like it has glitter in it, I would suspect a serious problem. If you want a better oil sample to study, you can stick a length of hose (e.g., 1/4 vinyl hose from Ace Hardware) down the dipstick and draw out an oil sample for closer inspection. Assuming the oil passes the "glitter" test...

Drop that pan and check for hard debris. If you find hard parts in the pan, take pictures and report what you find. Obviously this is an indicator of some issue within. If the pan's got hard debris, you may decide to simply put the pan back on and refill the trans with enough oil to allow you to drive it to a repair shop (been there, done that with my Suburban).

Check the amount of dust / fine debris in the pan and on the magnet. But... I can't tell you how to make a go / no go decision regarding the trans' condition based simply on the amount of dust / fine debris... too little experience on my part. Maybe someone else can offer guidance.

TOO... if you have any doubts about what you find, simply take the dirty pan, including whatever hard or fine debris or dust you've found within, undisturbed, to someone else (knowledgeable friend, transmission repair shop...) to examine.

Once you've done the above w/o concern, you can consider cleaning the pan / magnet, pulling / replacing the filter, and re-installing.

Those are my suggestions for now.

Well, maybe some others...

While I'm thinking about it: The O-ring on the trans filter neck sometimes sticks up in the valve body when the filter is removed. Be sure and fish that sucker out before installing the replacement filter (which should come with a new O-ring).

AND... the longer you let the transmission sit before (or while) changing the oil, the better, because the "old" oil in the converter will slowly drain out (and drip on you, if the pan's off) until the converter oil level has dropped to about 1/2 full. That way, when you refill, you'll be replacing more "old" oil with "new".

Anecdote: My K1500 Suburban was shifting funny (this was around 2013) so I prepared to change the filter and flush the oil. When I dropped the pan, I found little piles of large "dust" / metal pieces in the pan. "Oh oh, this isn't good". I took the pan to the local Chevy dealer (known them for years, small family operation) and showed it to them simply to confirm my suspicions... The end of the story is "remove / replace transmission and torque converter".

Anecdote: My 79 Camaro had problems with a 700R4 conversion and, for whatever reason at high RPM (converter ballooning?) it would shed a bunch of metal into the oil, which in turn would gum up the valve body and causing shifting problems. The metal particulates were fine enough that the oil on the stick would sparkle in direct light, like glitter in the oil. It did this twice to me, before I finally decided to get a more rugged torque converter; that remedied the problem.

 

[1500z71]

AB-so-LUTEly... particularly if you do it yourself. The primary benefit is it will give you a chance to assess the condition of the transmission. If you haven't dropped a trans pan yet, then ask for tips, here. Moving on...

First, I would pull the stick at look at the oil carefully. If it looks like it has glitter in it, I would suspect a serious problem. If you want a better oil sample to study, you can stick a length of hose (e.g., 1/4 vinyl hose from Ace Hardware) down the dipstick and draw out an oil sample for closer inspection. Assuming the oil passes the "glitter" test...

Drop that pan and check for hard debris. If you find hard parts in the pan, take pictures and report what you find. Obviously this is an indicator of some issue within. If the pan's got hard debris, you may decide to simply put the pan back on and refill the trans with enough oil to allow you to drive it to a repair shop (been there, done that with my Suburban).

Check the amount of dust / fine debris in the pan and on the magnet. But... I can't tell you how to make a go / no go decision regarding the trans' condition based simply on the amount of dust / fine debris... too little experience on my part. Maybe someone else can offer guidance.

TOO... if you have any doubts about what you find, simply take the dirty pan, including whatever hard or fine debris or dust you've found within, undisturbed, to someone else (knowledgeable friend, transmission repair shop...) to examine.

Once you've done the above w/o concern, you can consider cleaning the pan / magnet, pulling / replacing the filter, and re-installing.

Those are my suggestions for now.

Well, maybe some others...

While I'm thinking about it: The O-ring on the trans filter neck sometimes sticks up in the valve body when the filter is removed. Be sure and fish that sucker out before installing the replacement filter (which should come with a new O-ring).

AND... the longer you let the transmission sit before (or while) changing the oil, the better, because the "old" oil in the converter will slowly drain out (and drip on you, if the pan's off) until the converter oil level has dropped to about 1/2 full. That way, when you refill, you'll be replacing more "old" oil with "new".

Anecdote: My K1500 Suburban was shifting funny (this was around 2013) so I prepared to change the filter and flush the oil. When I dropped the pan, I found little piles of large "dust" / metal pieces in the pan. "Oh oh, this isn't good". I took the pan to the local Chevy dealer (known them for years, small family operation) and showed it to them simply to confirm my suspicions... The end of the story is "remove / replace transmission and torque converter".

Anecdote: My 79 Camaro had problems with a 700R4 conversion and, for whatever reason at high RPM (converter ballooning?) it would shed a bunch of metal into the oil, which in turn would gum up the valve body and causing shifting problems. The metal particulates were fine enough that the oil on the stick would sparkle in direct light, like glitter in the oil. It did this twice to me, before I finally decided to get a more rugged torque converter; that remedied the problem.

That’s pretty incredible and detailed advice on dropping the pan and inspecting everything. Thank you for that. But I would assume though even with changing the fluid and filter that still wouldn’t solve the Codes would it?

 

[Schurkey]

The same band activates in 2 and in 4. The servo assembly has two apply pistons, though. If the seals for the 2nd Gear apply piston are good, but the 4th gear piston seals are not, you could have "band" troubles in 4th gear but not in second.

 

[1998_K1500_Sub]

The same band activates in 2 and in 4. The servo assembly has two apply pistons, though. If the seals for the 2nd Gear apply piston are good, but the 4th gear piston seals are not, you could have "band" troubles in 4th gear but not in second.

Good comment, I had forgotten that detail.

 

[1500z71]

The same band activates in 2 and in 4. The servo assembly has two apply pistons, though. If the seals for the 2nd Gear apply piston are good, but the 4th gear piston seals are not, you could have "band" troubles in 4th gear but not in second.

Are the apply pistons right there at the pan or deeper in the transmission?

 

[Schurkey]

Accessible from the outside of the case--the 2--4 band servo assembly is the big, round, breast-looking thing just under the cooler tube ports. On some vehicles, you don't need to upset the trans mount, there's clearance between trans and trans tunnel for access. Other vehicles have tighter clearance, so the back of the trans has to be lowered, or you need a full bucket of harsh language.

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Servo upgrades are extremely popular--everyone and their brother has put a "Corvette Servo" in their 700/4L60/60E. That servo is for 2nd gear. There's also a big aftermarket servo for 4th gear. And, of course, folks sell a complete servo assembly with hot-rod parts for both 2nd and 4th gear.

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[1500z71]

I will do a fluid change and report back here. Thanks guys

 

[1998_K1500_Sub]

I will do a fluid change and report back here. Thanks guys

Take and post pictures of anything notable!