Transmission not shifting real great 2004 Yukon XL Denali

sefiro said:

High rpm shift points are normal for this generation of transmissions. Factory service manual spec shows a range of 1000 rpms from 12% throttle to wide open. +/-250rpm. Tow mode settings will raise this rpm range a bit.

A true rebuild sign would be burnt tranny fluid or material in the pan. A pan drop would ultimately be needed to see if a large number of metal shavings are stuck to the magnet. When replacing fluid, use dextron 6. It's fully compatible, synthetic, and recommended by gm for this generation of transmissions. Plenty of posts on how to change and not to use an external pressure pump.

If fluid is clear and minimal material (there is always a little bit after a new build break in), then valve body tune up, shift kit may be in order. You mentioned the dealer did some rebuild but did but give specifics. You'll need to drop the valve and inspect to see if oem or changed to a kit.

Your symptoms suggest the accumulate pistons/springs may be at fault (worn or broken). Or shift valves are leaking showing the shift point. These are accessed when when the pan and valve body is dropped.

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Thanks man. Is all Dex VI synthetic? I didn't know if I needed to go with some Royal Purple type stuff, or just Dex 6? I had planned on doing the "redneck flush", where you pull the line that goes from cooler back to tranny, run it through all gears for a bit while someone else dumps fluid down the dipstick tube. I think if I am going to go to an expensive full synthetic fluid, I will flush with cheap stuff, then change filter and put the expensive stuff in.

Yep, pull the upper hose to the radiator. Parts shops sell a short pipe that will fit the radiator, attach vinyl hose from it to 5G bucket. If you have a drain bolt remove and drain pan or Start engine, pump out 1-2g. Drop pan, do work as needed. Replace pan, add equivalent amount of fluid removed. Start engine, adding fluid add old fluid is pumped out of torque convertor etc. Once clear is coming out. Stop engine, match removed amount form newly added noting that removed amount should be greater than added. Use dipstick to confirm how much to add.

Sick with dextron 6 (all synthetic). Anything non dextron rated is likely to damage or mask problems.

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Thread cleaned up and all off topic posts removed.

Everyone play nice. This is you only warning.

I guess I missed whatever happened. Sorry if I did something wrong?

For those of you that talked about upgrading to a bigger transmission cooler, which one did you go to? I'm going to drop the pan tomorrow and see what I got going on, hopefully it don't look too bad....

Jeremy

Marinevet said:

I have a 2004 Denali with a 6.0/4L65E/AWD, with 135,000 miles on it. When shifting at low RPMs, it shifts decently ok, but at high throttle shifts (not floored, I don't drag race with it, but like you would use on an uphill interstate on ramp), when it goes to shift the engine revs up an extra 5-700 RPMs before it actually shifts, and the shifts are not very firm. This is most noticeable in the 2-3 and 3-4 shifts. Everything I am reading online says it is probably going to need to be rebuilt. I bought it from the dealer three years ago, and it was doing it then but a lot worse, so I made them rebuild it before I bought it. It only had 68,000 miles on it then though. There are no CEL codes for the tranny, and most of my driving is highway miles. Up until now, I have only pulled 3500 lbs with it twice, other than that I haven't towed anything. I have a 7000 lb bumper pull camper that I would like to pull with it, since I have a big family, but I won't do that until I get whatever is wrong with it fixed. What are your thoughts?

1. Does it need rebuilt, or could I try putting a shift kit in it first to see if that makes the shifts firmer?
2. Since I plan on towing heavy stuff with it, would it be worth it to buy a beefed up version of it and install it?
3. Is there something else I could check out first before I spend all that money on it?
4. In the meantime, if I push the towing button will that make it last longer for now?

Sorry for all the questions, I am getting fairly frustrated, because this is a great vehicle, rides like a dream, but if this is the second time in 70,000 miles that this transmission needs to be rebuilt that's going to suck. Thanks in advance for the opinions.

Jeremy

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Jeremy,

Glad this has been cleaned up...this thing is all over the place. I am confused. Some things you need to know and questions that maybe were asked that I missed.

1. The weakest point of these trucks are the tranny's, both the 4L60 and 4L65E. With that said, you doh't fix these. If you fix these, you will fix them again in a week. They have to be totally rebuilt. So when you say it was rebuilt at 68k, did you see an invoice? At 135k, that's when they normally fail, give or take.

Replacing the fluid is a waste of time. Damage is done. Towing will NOT change the life of the transmission. Urban Legend. Having your Tow Button on or off makes no difference.

At 68k, and the problems you are having, it sounds like they fixed it, not rebuilt it. Many people say get a remanufactured. A good shop, which is not A A MM Co, will give you the price going in. They do this in a day, and they do not need to diagnose this. A good shop will only rebuild this. Literally every single part has gotten a factory upgrade, so these usually fail the first week or they never see you again. Mine actually did fail, 3 times. Dealer was embarrassed, finally traced it to $.50 spring in the kit, had the wrong tension so 2-4 would not engage and slip. They diagnosed this by putting a Snap-on tool and drove it. Why are you pulling your pan? Waiste of Time!

You will find your pan. You need the invoice from the person who did this, you probably have zero recourse since you paid nothing, and they probably did not rebuild it. What warranty did they give you? Any? For free, doubt it.

This tranny should be around $1,900 out the door, totally rebuilt, 3 year/50k warranty. I have a couple of Yuki's, my 2000 SLT I upgraded from the 4L60E to the 4l65E because it cost $125 bucks for the upgrade, different planetary gear. So it sounds like you need a plan.

1. If you have not, contact dealer and get the paperwork. What did they do, rebuild means a lot of things.

2. Did you smell the fluid? It could be cooked and the fluid could smell ok.

3. Take it to a private shop, but call around first. You will get the prices up front or hang up. Some of these guy's go in to all of the crap they do, not different than what everyone else does, and try and get you for an extra grand. You will figure it out.

4. Go with them on the ride, most can do it with or w/o the scanner. the gears are linked. 1&3 or 2&4.

How do I know? Been through this before, more than once. I even have an extra laying around.

Don't chase rabbits, get this done and let us know.

The dealer showed me an invoice for around 1300 dollars, and I couldn't make out every line since a lot of things were abbreviated, but I did see a couple lines that were clutches and bands at least.

When I pulled the pan yesterday, it is actually really clean. Almost no residue of any kind. Fluid is a little darker than normal, but don't really smell burnt to me. Since I already have the pan off, I am going to pump the old fluid out of the tranny, re-fill with new full synthetic Dex VI and a new filter, and see if it helps. One thing I noticed as of late is that the tranny is running warmer as well, up around 200 degrees during normal driving (not towing anything).

One thing I did notice though, my trans pan doesn't have a magnet in the bottom of it. Have any of you run into that before? I thought they all did....

Also, whoever put the shift cable bracket mounting bolts on top of the transmission where you can't hardly get to them should be slapped!!! LOL

Jeremy

Initial run of a engine/tranny will produce some initial metal/ clutch material as surfaces mate. The magnet is used to pull the metal out of suspension as an aid to the filtration prices. It also aids the visual inspection process. You can operate without the magnet , but not recommended.

As for temp, you are pushing the higher end. Is this stop and go city driving?

Under a normal setup with driving mix, the radiator cooling should be fine you should be getting under 200 easily. When towing, the tow mode will delay the point to a higher rpm so the next higher gear will have enough rpm to prevent a stall. Higher rpm results in more friction and more heat. Thus tow packages are offered which include an additional cooler.

If you are picking up the load and jumping on the highway, then the std tranny radiator cooler will work fine (engine needs help as it is working harder). If you are bouncing around town or pulling on dirt, curved etc , then an additional cooler is needed.

Two basic types - tube and fin vs plate. Tube and fin is cheaper and likely prone to earlier failure. Plate matches oem stock and provides better cooling and installation options on the the std gm frame.

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Ok, I will see if I can get a magnet to throw in it. The 200 is when I have been doing more stop and go driving in town. On the highway, not towing anything, it will run around 160-180. It has been hotter than normal here lately too I guess. I'm hoping some of the temp problem was from the fluid needing to be changed. I will know shortly, I'm going to get fluid and a filter now to put in it.

Update:

I added 13 quarts of SuperTech Full Synthetic Dex VI fluid and a 24 oz bottle of Lucas Stop Slip Transmission additive when I put it back together with a new filter last night. I drove it to work this morning, and it is shifting better and the temps are running 10-15 degrees cooler so far also. I haven't drove it in town at all yet though, my commute is all highway. Before I catch a lot of sh*t for using the SuperTech fluid, I only used that this time because I wanted to make sure it was going to help. I figured if it didn't and the pan had to come back off, I didn't want to waste twice the amount of money on an expensive fluid. I'm going to keep an eye on it for awhile, and if it seems to be ok, I plan on putting a bigger external cooler on it (it has one now since it has the tow package, but it aint very big at all) and possibly a mild shift kit to help keep temps down if I tow with it, so at that point I will go with a better fluid as well.

A couple tips to help others: When removing the bolts to take the shift cable bracket out, if you unbolt the driveshaft from the front pumpkin and let it hang down, it makes access to the bracket bolts a LOT easier. Also, since the one closer to the front is harder to get to, if you remove the back one, you only have to loosen the front bolt to get the bracket to swing out of the way enough to drop the pan, no need to fully remove the front bolt. Also, if you want to use a great synthetic fluid, most places have to order it ahead of time, so make sure you plan ahead enough for that LOL.

Thanks again for all the help, I will update if things change.

Jeremy

Have a 2004 Tahoe and for 2 years if driven normal, easy and trans would flare up 500-1000 rpm mostly on 2-3 shift most of the time. I used to be Ford Tech in 80's and 90's so I know how to work on cars. It never set a code, never discolored the fluid but changed a few times just to see if it would help. Nothing! Mine started to flair a little more lately up to 1500-2000 rpm. If you google this problem you'll see many complaints and is kinda a typical problem with the 4L60E trans. Last month I decided to redo the Tahoe completely so I went to trans exchange where they Dyno every trans and comes with new converter. $1750 It's all good now and every shift solid feels really good and I definitely enjoy driving it more now. I got a boat and just didn't want to wait for it to totally fail at the wrong time. Good luck.