3-4 transmission wander

[meerschm]

Noticed that as she warms up, around 50-55, if I am being easy, the transmission will wander some between 3rd and 4th. might be coming up a slight hill, but not so much you would think it needs to downshift.

Not sure if this is new, since I mostly drive at 65 or 70, (ok, perhaps a bit more if it is safe)

is this a common detail, or should I be worried?




(also wonder why I cannot edit the title)

 

[ScarabEpic22]

I doubt its actually the trans hunting for 4th gear unless you've got a trailer behind you. Sounds more like the TCC cant hold the desired pressure and is letting the torque converter come out of lockup. Check the trans fluid level first, then if you havent changed the fluid in a while Id drop the pan and replace the filter + ~5qts of fluid. When you do that, look at getting a Superior products 4L60E P1870 TCC lockup fix kit. Its pretty cheap, less than $50 IIRC. It has a bigger valve for the TCC and applies more pressure during lockup.

Do you have a tune? One of the things I fix in my tunes (all unless someone doesnt want it) is to change the TCC apply and release PWM %s to more of an "on/off" style lockup like this kit. Doesnt work as well as actually installing the hard part, but it definitely helps.

 

[meerschm]

No tune

View attachment 23701

here is a graph of my ride home today.first part is me checking trans fluid cold after going through the gears.

wandering behavior is around 7 minutes and more pronounced around 8 minutes. do you think this looks like lockup going in and out?

this program does not show actual transmission readings.

thanks for the input. I will look into your suggestion.

 

[meerschm]

I doubt its actually the trans hunting for 4th gear unless you've got a trailer behind you. Sounds more like the TCC cant hold the desired pressure and is letting the torque converter come out of lockup. Check the trans fluid level first, then if you havent changed the fluid in a while Id drop the pan and replace the filter + ~5qts of fluid. When you do that, look at getting a Superior products 4L60E P1870 TCC lockup fix kit. Its pretty cheap, less than $50 IIRC. It has a bigger valve for the TCC and applies more pressure during lockup.

Do you have a tune? One of the things I fix in my tunes (all unless someone doesnt want it) is to change the TCC apply and release PWM %s to more of an "on/off" style lockup like this kit. Doesnt work as well as actually installing the hard part, but it definitely helps.

Where do you think I could get the kit? what is involved in the replacement?

I have pulled the transmission pan on my old Astro a few times, but not done much more than change the filter and clean out the pan when it was off.

Is this what you are talking about?

http://www.superior-transmission.com/Product_Page.cfm?ID=76

 

[meerschm]

I doubt its actually the trans hunting for 4th gear unless you've got a trailer behind you. Sounds more like the TCC cant hold the desired pressure and is letting the torque converter come out of lockup. Check the trans fluid level first, then if you havent changed the fluid in a while Id drop the pan and replace the filter + ~5qts of fluid. When you do that, look at getting a Superior products 4L60E P1870 TCC lockup fix kit. Its pretty cheap, less than $50 IIRC. It has a bigger valve for the TCC and applies more pressure during lockup.

Do you have a tune? One of the things I fix in my tunes (all unless someone doesnt want it) is to change the TCC apply and release PWM %s to more of an "on/off" style lockup like this kit. Doesnt work as well as actually installing the hard part, but it definitely helps.

Just was reading a post from you five years ago on the OS. sounds like the same issue.

 

[ScarabEpic22]

Sorry, I had an indepth reply ready to go and then the site crashed (been happening a LOT to me lately).

Yes, thats the exact link I was going to post, the 4L60E PWM Power Valve.

And I want to say THANK YOU FOR THE LOG!!! Makes a huge difference when diagnosing these issues! If you lightly press the gas more, do the RPMs fall right back down? If they dont, then its likely the trans is actually shifting into 3rd, if it the RPMs do fall right back down its the TCC not getting enough fluid to sustain lockup.

Here in a few weeks Ill have the ability to bench flash PCMs and do a few mail order tunes, if you want to try the tweaks Im talking about Id let you try it out for the cost of shipping the PCM both ways. If you decide you like it and the rest of the tune (regular full tune), just pay the remainder. If not, throw it in a flat rate box and you're only out ~$20. Ive got 3 spare P10 PCMs Im trying to get rid of so Im thinking around $150-175 shipped for a tune+PCM.

 

[Sparky]

I fixed this on my old car (same transmission) with a transgo kit. I went the whole 9 yards and got a kit that also had a new separator plate, accumulators, etc. Worth it IMO if you plan on keeping the vehicle a long time.

 

[meerschm]

I will do another run today. the tune sounds like a possibility. how exactly does that work? do you need a record of operation to calibrate the program settings closer to the specific behavior of the individual engine/vehicle? the OBDWiz package I have records .tdl and .csv.

there is another item of note.

I have a hard time getting a hot trans fluid level reading. shows a few inches above the full level warm, with one side slanted. (other thread discussed this some)

cold, it was reading full in the cold area of the indicator (dip stick)

so I pulled a little under a pint out late Sunday, with my Pela extractor.

what I did was pull a bit out not running, and then pulled my power steering fluid to change.

started back up, ran through gears, and checked again, still high, so I pulled some out with the engine still running. seemed like the fluid came out full of bubbles. could be this is related to why the fluid indicates high when warm.

it was close to the bottom of the cold range yesterday at the start of this run.

I have an IR thermometer, I will check the cooling lines (which I changed a couple weeks ago). they both felt warm yesterday.

in the mean time, I need to go vote on the way to work.

 

[meerschm]

View attachment 23725
View attachment 23726

the funny stuff is just before and after three minutes.

I gave it a bit of gas after a few cycles.

 

[dfc739]

This is a very common problem with this transmission. When mine started dying it would bounce the RPMs around when trying to lock the converter around 45 mph. If I gave it any gas at all, it would unlock the converter but if I let up it would lock it. If it gets bad enough, it might throw a P1870 code. You should search google for "4L60E and P1870". There are tons of results. I installed the Transgo SK4L60E shift improvement kit which fixed my problems and drastically improved my shifts. I know it looks like a lot of parts, but it comes with in-depth instructions.

TransGo | 4L60E, 4L65E, 4L70E and 4L75E: SK 4L60E

There are also other kits to fix shifting or you could just buy the valve. I bought the Transgo because it has great reviews and didn't require any physical modifications to the valve body itself (something I was NOT comfortable doing as a home mechanic). My writeup on this is at http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/. The specific valve you want to replace (Torque converter clutch pulse width modulated or TCC-PWM for short... Transgo calls is the ISO-conv valve or something close to that) is the very bottom one in Pic 12. It's hard to see due to my shadow but it's an outer plug with two pieces and a spring between them. While you're in there you should also change out the plastic accumulator pistons and separator plate too. Transgo also makes replacement separator plates that are thicker and stronger.

 

[Sparky]

This is what I got:

4L60E 4L65E 1996 2006 1870 P1870 Code Buster Combo Kit Corvette Servo Kit Book | eBay

Both 4L60E transmissions I have are operating flawlessly after the kits and both have over 160k on them now. The one was having severe TCC issues before the install too.

Vette servo is a pain to install because of where it is located, but lower the crossmember and it can be done. Really my main reason for getting the vette servo was you're getting into that servo with the transgo kit anyway, and you tend to mess up the original O rings when opening it up, so it comes with the new O rings you'll need.

While you have this all apart it would be a good time to check your trans cooler lines for rust/pending failure and replace if necessary.

 

[meerschm]

This is a very common problem with this transmission. When mine started dying it would bounce the RPMs around when trying to lock the converter around 45 mph. If I gave it any gas at all, it would unlock the converter but if I let up it would lock it. If it gets bad enough, it might throw a P1870 code. You should search google for "4L60E and P1870". There are tons of results. I installed the Transgo SK4L60E shift improvement kit which fixed my problems and drastically improved my shifts. I know it looks like a lot of parts, but it comes with in-depth instructions.

TransGo | 4L60E, 4L65E, 4L70E and 4L75E: SK 4L60E

There are also other kits to fix shifting or you could just buy the valve. I bought the Transgo because it has great reviews and didn't require any physical modifications to the valve body itself (something I was NOT comfortable doing as a home mechanic). My writeup on this is at http://gmtnation.com/f93/how-remove-4l60e-valve-body-replace-plastic-accumulator-pistons-4972/. The specific valve you want to replace (Torque converter clutch pulse width modulated or TCC-PWM for short... Transgo calls is the ISO-conv valve or something close to that) is the very bottom one in Pic 12. It's hard to see due to my shadow but it's an outer plug with two pieces and a spring between them. While you're in there you should also change out the plastic accumulator pistons and separator plate too. Transgo also makes replacement separator plates that are thicker and stronger.

I saw your video, (and commented on the chair) looks pretty complicated Have to think if I want to bite this off.

 

[meerschm]

This is what I got:

4L60E 4L65E 1996 2006 1870 P1870 Code Buster Combo Kit Corvette Servo Kit Book | eBay

Both 4L60E transmissions I have are operating flawlessly after the kits and both have over 160k on them now. The one was having severe TCC issues before the install too.

Vette servo is a pain to install because of where it is located, but lower the crossmember and it can be done. Really my main reason for getting the vette servo was you're getting into that servo with the transgo kit anyway, and you tend to mess up the original O rings when opening it up, so it comes with the new O rings you'll need.

While you have this all apart it would be a good time to check your trans cooler lines for rust/pending failure and replace if necessary.

I have brand new cooler lines from a few weeks ago. they were pretty rusty. had the trans dropped a bit two weeks in a row. so I am pretty good at it now.
(35 and 37 Ft LB for the mounting bolts)

 

[meerschm]

Didn't I read someplace that the Superior parts were better than the TransGo, or was that monkey spit from someone?

I am thinking about this or something similar. might be a better match for my skills and interest.

http://www.trutechtrans.com/ACDelco-Valve-Body-25075449.html

my trans was replaced with a Gm rebuilt at 104kmiles in Jan 2008. not sure the valve body was not bored out as part of the rebuild, which might make a kit have some issues.

 

[dfc739]

I saw your video, (and commented on the chair) looks pretty complicated Have to think if I want to bite this off.

I was also unsure at the time. Now I'm very glad I did. Just make sure you give yourself plenty of time to install everything. The last thing you want to do is rush and forget or lose something. It'll probably take a weekend to install everything. Maybe start Friday evening with dropping the pan and removing the valve body. Once inside or on a workbench you can swap out valves, springs, and pistons. Then the next morning will be dropping the crossmember to pull out the servo. Then put everything back together. You could even do like what OctaneRider did with working on his engine and live webcast it. Then we can all sit around and scrutinize your every move...

Didn't I read someplace that the Superior parts were better than the TransGo, or was that monkey spit from someone?

I've heard the same but I've also heard others say Sonnax kits are the best. It's probably about as highly opinionated as people are about tires/oil/you name it.

 

[Sparky]

I don't know, but I've had zero issues with my transgo kits and they have been in there for a combined 65K+ with no issues and no symptom returns. No special tools were needed with the transgo kit, not sure about the others.

Since I've had great success with both times I've used Transgo they're the ones I recommend. Hard to argue with a flawless repair and a parts cost of only $150 for an entire valve body upgrade kit from that one seller on ebay (then plus fluid and filter of course).

 

[meerschm]

I apreciate all the helpful suggestions, but I think I may be closing on my real problem.

Yesterday I rolled the rear tires on a couple boards to get closer to level in my driveway (two and a half inches, used a 2x4 and a 1x4 stacked)

checked level running, cold, and the level was way low. added a quart of fluid. brought it into the cold range on the indicator.

( I had in the past few weeks changed the transmission to radiator lines, and had pulled half a quart thinking it was overfilled.)

drove a circuit up one freeway exit and back. and hot, the trans reads high a couple inches. what I think is happening is that the level is still low and pulling air which makes the warm level read high.

this morning the cold running level still reads at the low end of the cold scale, but within the cold low-high area.

drove the same route to work, and she is solid, drove around 50 -55, and even with light accelleration, steady as she goes.

Does not look like I need to rebuild or replace the valve body, as much fun as that looks like. just need to get the fluid level correct.

 

[Sparky]

Next time you do transmission service I'd still recommend installing that transgo kit, just because of the tendency of the 4L60E to have TCC issues and such that can end up resulting in burnt bands and whatever else.

 

[meerschm]

Didn't I read someplace that the Superior parts were better than the TransGo, or was that monkey spit from someone?

I am thinking about this or something similar. might be a better match for my skills and interest.

ACDelco High Performance 4L60E Valve Body With Solenoids | Trutechtrans.com

my trans was replaced with a Gm rebuilt at 104kmiles in Jan 2008. not sure the valve body was not bored out as part of the rebuild, which might make a kit have some issues.

I actually ordered the valve body package, on line Wed morning.

By Thursday, I figured out I wanted to check the fluid, and called Jeff, who caught the order before it shipped, and when I called him today to cancel, he said he would credit the paypal and cancel the order. Jeff seemed like a nice guy, and was nice on the phone. if anyone decides to replace the valve body instead of parts, or other trans stuff, I can at least say he answers the phone and seems reasonable.