Chevy Suburban Transmission Problem

1999 Chevy Suburban, 350 V8, auto, 219k miles The transmission has been acting weird for a little over a week now. When the vehicle is first started and cool, everything operates perfectly. However, as soon as the engine reaches operating temp, the transmission acts up. It will never downshift into first gear, regardless of speed or gear selection, even dropping the transmission into 1. Plus, the truck will never shift higher than 3rd gear, it only shifts between 2nd and 3rd, never using overdrive regardless of speeds at 60+. The ATF level is where it should be. I read the thermostat could be bad, and when the engine reaches operating temp something happens that will not allow the truck to shift properly. Anyone think this makes sense? Dr. Tranny shudder fix was used 70 miles ago to no avail. Sea Foam tranny tune will be used today.Anyone have any ideas to try?Dave

sounds like it’s time for a new one. How long and how much use will the vehicle continue to see would help me determine how much to put into it but it’s your vehicle and your call. One thing that has worked some is to drop the pan and take out the shuttle valve and clean those ports out good, may help it last a bit longer if that’s what you are looking for. Good luck.

Is it the original? If you got 219k and its an original tranny I wouldn’t ask why its acting up. By you saying it works good when cold but when warms up you start getting issues, my first question is when was the fluid last changed? The fluid could be worn out and not giving it the proper protection. Does the fluid smell burnt?

I had the same truck, same year. It had 85,000 miles when the transmission went out. Towing a light trailer into a strong N Dakota headwind. I then learned the GMC & Chevy 1/2 ton pick ups and Suburbans had a lot of transmission problems in the late 90’s and early 00’s models. Mine cost $2500 to overhaul. They told me there were 18 engineering changes incorporated into the rebuild. Like was already said if there are 219K miles on the original you did very well. Good luck.

had a 99 suburban and tranny went out at 70,000 miles and had a couple of torque converters go out after before they got it straitened out. Cost $2500 for replacement.

Sounds like a valving or pressure issue… (not limp in mode) like said, at 219K, it doesn’t owe you anything. Sounds like cold test drives off of craigslist

One could do a tranny flush and change the fluid and hope for the best.

My bet, the tranny has seen it’s better days.

If you can change the tranny yourself, I might look into a junk yard tranny.

The worse you would be out is the tranny install time and typically the salvage yards will return a questionable tranny.

I have replaced 2 tranny’s from the salvage yards in 2 different GM trucks with good luck.

Just might be an option for you.

Now, if you have to pay another to do the repair work, then I would look at a new or rebuilt tranny.

had same tranny got to 300 but really had to stay on top of it. i chose to rebuild mine. great shop. no problems with the new one. hope they got the upgrades in the kit!!!
i’d change the fluid and see what happens…

My 03 1500 went out last fall at 86K Was just shy of $2500 for a new replacment with 3 yr warranty.

Drained the pan, no metal filings inside, all looked clean. Replaced the fluid and gasket, added Trans-Tune and some Lube Guard. No change in performance, still shifts poorly. So I guess the tranny is dying. It’s very old and my son is driving it, so I don’t want to put much money into the truck.

Dave

Have you disconnected the battery latley. Sometimes it takes a while for the computer to relearn how to shift.
That year of Sub has issues. I had to replace my tranny after 52,000 2k after warrt. was up. Call 651-464-8498 ask for Mark. Tell him Shawn sent you. He has 40 yrs exp. will give you a straigt answer.

I had a similar problem with my 95… one question… does the check engine light come on when the problem starts? if so it could be like mine, ended up being a 50 dollar , easily replaced part,

YES, ROSCOE, the Check Engine light does come on. What do you suppose it could be? I love an easy fix.

Dave

we used a snapon scan tool and traced the problem to a little solenoid in the tranny , accessed by taking the tranny pan off and replacing the part…. was an easy fix once we found out the problem, find a mechanic with a good scan tool and Alldata on his computer ,
Roscoe

Do any of the mechanic types on this thread think I might have a good chance of fixing the tranny with a shift solenoid repair? That would be a great low cost fix.

Anyone?

Dave

I am not totally familiar with GM, but if it’s not slipping, and is mostly shift issues, with a MIL, I would lean towards an electrical/solenoid/valving issue as well

If you are east side, run it out to Dave’s Tranny in River Falls and tell him Stu Sent You and he’ll tell you the truth.

Considering that it is not slipping, you do have a shot at a cheap fix. Don’t know the ratio of bad solenoids to the other upgrade problems in that overdrive tranny.

I’ve had two of them. One went at 150k, the other at 300k (and i abused it).

Dave will tell you the truth and i’m sure he’ll have the testing you need. Don’t go at 4:55 as some of his techs leave something to be desired. (yes, i get tired at 4:55 too)

Thanks, Stuwest, but the truck is in Arkansas. Don’t ask why the kid is in Arkansas, but a girl is involved

I have a 1999 suburban with 150K miles. It shifts fine at first then shifts very hard after it is hot. I fixed it by replacing the valve body and all 5 shift solenoids. It works better then new. If the tranny acts up and you stop the truck, shut it off , wait 4 minutes then start and go again and it works for a while then it is solenoids that are sticking. The valve body and controller on mine was full of gunk. 2 of the solenoids were bad. A new valve body replacement kit with gaskets and solenoids is $189.00 $200 to replace. Total $389.

To me it sounds like a solenoid issue. Most likely it is getting hot because it is no longer working properly.

I have a 99 suburban also. They have the 4l60E transmission in them. YOu can find a junkyard 4l60E pretty cheap. Heck I have seen basic rebuilt ones go for around 700.

Hopefully his kid hasn’t been stuck down there for 5 years..
DT

I have a 2003 Suburban not shifting to third. Replaced trans. (twice because we thought we had a bad first trans.) Still does the same thing. Scan tool said to replace shift solenoid. Did that and still same problem. Trans is a 4L60E. Does anyone have a picture of the internal solenoid ROSCOE is talking about? Or can it be the PCM?

my 00 silverado tranny would not operate at all for about 30 seconds after it started. whether warm or hot. was very wierd. It also hated down shifting and once i hit 170k miles it started dropping into limp mode on a regular basis. especially when hauling my boat. I would have to let it sit a sec.

My FIL used to run a business with a fleet of silverados and his mechanic said that the late 90-00’s chevy truck transmissions were absolute garbage. they basically had to rebuild every single one around 55-75k miles. when i bought it with 90k miles on it, he was like its likely its already been rebuilt, i’d have no problem owning it.

I agree if it doesn’t slip its more valving or solenoids. The tranny tune can take more than just a few miles to do its thing. Last time I used it was almost 1,500 miles before it did clean the valve body and smoothed out the shifting issues. Dealer wanted $5,200 for rebuilt tranny. $7 can of Sea Foam Tranny tune fixed it.

Old thread and an even older problem on a worn 4L60E. Hope for the best that it’s just the solenoid, but don’t bank on it. it’s a very common issue. So common, in fact…

Just be lucky you don’t have 4 neutrals…

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