Automatic Transmission - slight surge from 1st to 2nd

[Jerome Nelson]

2000 LT 5.3L V8 2WD Tahoe, automatic with 200,000 +/- miles.

History:​

Automatic transmission was completely rebuilt about 6 years ago.

About a year ago, the transmission started slipping with some hard shifts. The transmission fluid looked normal (for the age). I removed some transmission fluid and added 24 oz. of Lucas Transmission Fix. This made it run a lot better, but not perfect. Added a 2nd 24 oz. bottle of Lucas Transmission Fix. This fixed ALL of the slipping and hard shifts! No issues with this since.

However, I still have a slight surge (about 400 rpms) when my automatic transmission shifts from 1st to 2nd when it's cold. It'***** or miss when warmed up to full temperature.

As I've been told, there is a good chance it's just the "transmission going". I'm not really in the place to spend thousand of dollars rebuilding/replacing this again. I was wondering if anyone had similar experiences with this. I'm open to other thoughts.

I also have a suspicion that it could be the Shift Solenoids and I'm considering replacing myself. I'm not sure if these were replaced when I had it rebuilt. It's just a lot to get into if this isn't it. Still, at 200K, it couldn't hurt (other than time and money).

 

[OR VietVet]

Have see where the shift solenoids are pretty easy to replace and would be perfect time to change the filter and refresh the fluid. Look at you tube videos of the solenoids replacing.

You mentioned adding the Lucas fluid but I did not see where you had done a fluid flush or filter. Good luck.

 

[Jerome Nelson]

You mentioned adding the Lucas fluid but I did not see where you had done a fluid flush or filter. Good luck.

I didn't flush or replace the filter, as the transmission fluid looked ok, and was replaced with the transmission about 30-40k ago. I pulled some of the old transmission fluid out, just to make room for the Lucas Fluid, with a fluid transfer pump (Harbor Freight) - out from the dipstick shaft.

Yes, I watched a few YouTube videos on replacing the Shift Solenoids. It doesn't look that hard at all — just messy! But, before I tried that, I wanted some feedback from others to see if this might actually be causing the shifting issue. As I mentioned, I'm not sure if these were replaced with the transmission rebuild?

 

[OR VietVet]

Just trying to understand, you are saying that you drove the rig, after the new trans, for 6 years and never once in that time did you do the fluid or filter change? When you said "completely rebuilt" are you talking about everything was done but maybe the solenoids were not replaced. On a completely fresh transmission, I would have done fluid and filter change at about 20k to 25k miles and checked everything that comes out. That is just me though.

 

[Jerome Nelson]

Just trying to understand, you are saying that you drove the rig, after the new trans, for 6 years and never once in that time did you do the fluid or filter change? When you said "completely rebuilt" are you talking about everything was done but maybe the solenoids were not replaced. On a completely fresh transmission, I would have done fluid and filter change at about 20k to 25k miles and checked everything that comes out.

Yes, that is correct. I'm not a mechanic, nor do I play one on TV. It's only in this last year that I've had the time to really get into all this. Also, we only put about 5-10K miles on this vehicle a year. I didn't expect to have to mess with it until the 60K transmission fluid replacement.

In retrospect, I wish I knew a lot more - especially over the last few years. I assumed that rebuilding the transmission would have taken care of all of the issues (which it did for 5+ years). I now know that all transmission mechanics are not created equal! But, I thought the transmission would be good for the "life" of the vehicle since it has nearly 200K miles on it already.

I honestly don't know about the solenoids. I don't know if it's part of the rebuild or not. Is this standard? How long should they last?

 

[OR VietVet]

I base my "assumptions" off of the phrase, "completely fresh transmission". At this point I hope a transmission specialist chimes in, like @rockola1971 for instance. Moving on, with any work you have done on your rig by any shop, always get a detailed breakdown of what was done, parts and labor. That helps take some of the guesswork out of these problems. If a shop will not do that, then walk away.

 

[Mudsport96]

It is called a flare when it revs between shifts. A worn 2-4 band can cause that and so can a 2-4 servo pin thats not the correct length. Also worn valvebody components can be a cause. If you arent too comfortable with transmission work, find a reputable transmission shop in your area to take it to be checked.

If you are fairly confident you could open one up and do some work, order a transgo hd2 kit to install in the valvebody and a Corvette 2-4 servo assembly in the case. Should, repeat Should fix you up.

My guess, without seeing or driving it. Based off of your description is a worn 2-4 band or apply pin for said band is too short, so it takes a second to fully apply and stop the drum.

 

[rockola1971]

Id be interested in the state of the fluid. Is it burnt smelling? Bright pink or more brown to orangish in color? Id also be interested in the receipt from the transmission shop to show what work was done? Were all valve body updates performed? (We will get back to this). The Lucas and other brand additives for transmission do 2 things. (1) soften up hard seals (Orings) and cause them to swell and seal better. Once a seal is hardened up enough and been hot enough no additive in the world will save it. (2) lubricate and free up valves in the valve body. The valve body is essentially the hydraulic computer for your tranny. I suspect you have been having a problem with atleast one valve sticking in your valve body which is why I am curious if the tranny shop receipt shows the valve body updates being performed. Typically when a shift solenoid fails there is no in between. It either works correctly or it is burnt electrically open and never works again. It is just a coil of wire that sucks up a metal plunger and then releases when applied voltage is taken away.
The 1-2 shift surge could be alot of things including a slipping 2-4 band, 2-4 servo sticking in its bore, A prematurely worn 2-4 band caused by valve body problem with sticking valves. If the separator plate was serviced/replaced it could have beaten seats that check balls are sticking in and causing havoc. Nothing will end well if that is the case. It wont get better then. Dropping the pan and inspecting the filter contents and seeing what is laying in the bottom of the pan will tattle on the possibility of worn 2-4 band. There will be lots of "brake dust" looking material laying in the pan.
You are going to have to find a shop that truly has a reputation for only performing work that is necessary. Too often you will run into shops that just want to yank it all out and do a total rebuild and sometimes depending on the damage that is necessary but others not. For instance a front seal walking out requires a tranny drop but sure doesnt require a total rebuild. Heck the tranny doesnt even need to be opened up for that. But a noisy planetary which is in the very rear of the tranny but can only be accessed from the front and doing a total teardown you might as well have it all rebuilt while in there.
It could be worth the hassle of finding atleast 2 reputable shops then have them do a diagnostic and repair estimate and compare them. See if they even say the same thing is wrong. They both arent likely right if they are saying 2 entirely different diagnosis.

 

[Joseph Garcia]

Id be interested in the state of the fluid. Is it burnt smelling? Bright pink or more brown to orangish in color? Id also be interested in the receipt from the transmission shop to show what work was done? Were all valve body updates performed? (We will get back to this). The Lucas and other brand additives for transmission do 2 things. (1) soften up hard seals (Orings) and cause them to swell and seal better. Once a seal is hardened up enough and been hot enough no additive in the world will save it. (2) lubricate and free up valves in the valve body. The valve body is essentially the hydraulic computer for your tranny. I suspect you have been having a problem with atleast one valve sticking in your valve body which is why I am curious if the tranny shop receipt shows the valve body updates being performed. Typically when a shift solenoid fails there is no in between. It either works correctly or it is burnt electrically open and never works again. It is just a coil of wire that sucks up a metal plunger and then releases when applied voltage is taken away.
The 1-2 shift surge could be alot of things including a slipping 2-4 band, 2-4 servo sticking in its bore, A prematurely worn 2-4 band caused by valve body problem with sticking valves. If the separator plate was serviced/replaced it could have beaten seats that check balls are sticking in and causing havoc. Nothing will end well if that is the case. It wont get better then. Dropping the pan and inspecting the filter contents and seeing what is laying in the bottom of the pan will tattle on the possibility of worn 2-4 band. There will be lots of "brake dust" looking material laying in the pan.
You are going to have to find a shop that truly has a reputation for only performing work that is necessary. Too often you will run into shops that just want to yank it all out and do a total rebuild and sometimes depending on the damage that is necessary but others not. For instance a front seal walking out requires a tranny drop but sure doesnt require a total rebuild. Heck the tranny doesnt even need to be opened up for that. But a noisy planetary which is in the very rear of the tranny but can only be accessed from the front and doing a total teardown you might as well have it all rebuilt while in there.
It could be worth the hassle of finding atleast 2 reputable shops then have them do a diagnostic and repair estimate and compare them. See if they even say the same thing is wrong. They both arent likely right if they are saying 2 entirely different diagnosis.

Thank you for your post @rockola1971 . I just got a great overview education on the transmission, and that is why this Forum ROCKS!

 

[Jerome Nelson]

Hello All,
I'll definitely look into all of the items stated above. In the meantime, I found the original invoice for the transmission rebuild...

I can't make out most of the chicken scratches, so I attached a couple of images.

Any insight you can give on this would be greatly appreciated!!