Engine speed blips around at 45-60mph

[6716]

How will I know when I have the right amount of fluid left in the transmission?

So I had the transmission cooler lines replaced and the fluid seems to have been overfilled. At least, the slippage has moderated as I have slowly removed fluid from the system. Performance was consistent with an overfilled transmission at least as far as I have read. Engine speed was bouncing pretty aggressively at speeds above 45mph. I have been slowly pulling fluid out and seeing how it works.

Had the truck on the road for a camping trip this weekend and I noticed that when I am running down the freeway at 75-80 and the tach is at 2K-ish, I don't have any problems. And no problems in slower speed situations.

But when the transmission is hot and the throttle inputs are a little more vague, like I'm maintaining a speed of 55 on a flat stretch, the engine speed will pop up and down a couple hundred rpms. Sometimes it will lug a little, sometimes there's some shudder that I can't attribute to road conditions.

Now, I was kind of hard on the transmission. It took me a while to grudgingly admit that I needed to have someone do the cooler lines for me, and I dropped all the fluid a couple of times, so there may be some damage.

I can keep taking fluid out, and I've read here in a couple of places that the dipstick is basically useless ... but how do I know when the fluid is probably right on and if I still have issues that it might be some other cause?

 

[Tiggerr]

Sounds like it my be the TCC issue common to these transmissions. There's a kit to fix that. There's a few threads on that issue. Basically you replace the TCC solenoid in the valve body. There's a whole shift kit that includes that. Fixes the mushy shifting these trans are known for as well

http://www.ctpowertrain.com/2004r-700r4-700-4l60e-4l65e-new-lock-up-solenoid-kit/?page_context=category&faceted_search=0

 

[6716]

Sounds like it my be the TCC issue common to these transmissions. There's a kit to fix that. There's a few threads on that issue. Basically you replace the TCC solenoid in the valve body. There's a whole shift kit that includes that. Fixes the mushy shifting these trans are known for as well

http://www.ctpowertrain.com/2004r-700r4-700-4l60e-4l65e-new-lock-up-solenoid-kit/?page_context=category&faceted_search=0

Thanks for the direction.

The part is inexpensive. Opening the transmission gives me the willies.I've done the pan drop and filter change. Is this the sort of thing you're talking about?

http://forums.offroadtb.com/viewtopic.php?f=26&t=3022

 

[Tiggerr]

Your just going into the valve body. Not too bad. I'd do the shift servo too if you do the whole shift kit. It's on the side of the trans on pass side. Round cover

IIRC. A way to check the TCC is to hold your speed steady in 4th gear and while your foot is still on the gas tap the brake. RPM should jump a couple hundred RPM. If it does then it's locked in. Maybe try it around the speed your having issue with. Most PPL I've seen is always around the speed you spoke of....45-60.

That RPM fluctuation your talking about seems to be the giveaway from what I've read.

 

[BlazingTrails]

I agree about the TCC lock up. it can also be adjusted in the tune by bumping up the pressure. So you could either do the shift kit as mentioned above or have your truck tuned. PCMofNC or Limeswap are the preferred vendors.

You should definitely do the Corvette servo, it is a great upgrade and very affordable.

 

[Sparky]

To answer the question - you know when you have the right amount of fluid in the trans by checking the level on the dipstick

Another vote for the CTpowertrain kit. There are a lot of pieces to keep track of, yes, but just do one step at a time and keep them in order and you should be fine. It isn't that bad if you are organized. As mentioned, it is only the valve body, not like you're getting into clutch packs and stuff.

I had that kit totally fix my 4L60E in my car. Went from bouncing RPM, to always staying high, to high trans temps and slamming shifts. Put the kit in once I read about what it fixes and sure enough it took care of everything. That was many thousands of miles and a few years ago. Been perfect since.

I now install that kit in every 4L60E I get when I do my first transmission service, just as preventative. I'm pretty sure that is what has helped my Trailblazer get to 211k (and counting) without nary a hiccup. Even fluid aging quality is improved.

 

[gmcman]

Yes, the distick is the correct method. With the trans hot, engine idling, level ground, pull dipstick, wipe, then reinsert and check the level.you may need to rotate the dipstick to check the backside but look for the straight edged line of fluid.

These trannys pound the snot out of the seperator plate with the steel check balls, eventually causing leaks or even pressing one of the check balls through the hole.

If you have at least 150K, I would strongly recommend changing the plate, also inspect the accumulator pistons while you have the valve body out.

Like others stated, this is a great time to perform the TCC eliminator, cheap and easy.

MY TCC eliminator thread. BTW, The pics uploaded backwards in the beginning of the thread. http://gmtnation.com/forums/topic/7238-removed-pwm-control-from-tcc/?hl=%2Btcc+%2Beliminator

 

[6716]

Ok, the transmission stuff is totally new to me. Can you point me to a how-to on the CT powertrains kit?

Thanks

 

[Sparky]

It comes with directions on how to install all the stuff actually. It should come with the hardened separator plate (you'll still want to follow directions for any hole drilling).

If I remember I'll try to do some directions when I do my install on my Silverado's transmission. Big IF there, as I tend to get involved in the process of doing something and totally neglect to take pics along the way for most of my projects

 

[Mooseman]

As well as using the included instructions, I followed these instructions with pics from ORTB:
http://forums.offroadtb.com/viewtopic.php?f=27&t=4507

 

[6716]

Thanks everyone for the direction. I'm in full study mode. I'll probably read for a couple of weeks and then get the parts and then go for the repair. I have learned a lot already. So much to learn ....

 

[6716]

I just ordered the shift kit but I am not sure that it includes http://www.ctpowertr...aceted_search=0 .

I suppose I'll know more when it arrives.

Just started to get some really hard shifting 1-2 and 2-3 when it's hot. Commuting to work or running out to do an estimate I don't have any trouble with those shifts, as long as the appointments aren't too far away.

 

[Sparky]

No it does not, but the only time you need that solenoid is if your original is dead. Odds are, it isn't dead.

 

[gmcman]

Make sure your brake pedal isn't out of adjustment or allowing the brake lights to come on while driving. Applying the brakes, as little as just turning the brake lights on will unlock the torque converter.

 

[6716]

No it does not, but the only time you need that solenoid is if your original is dead. Odds are, it isn't dead.

Ok. In the first few replies I thought I understood that solenoid would help with the torque converter clutch lockup. Or does the shift kit contain a different fix for the lockup problem?

 

[6716]

Make sure your brake pedal isn't out of adjustment or allowing the brake lights to come on while driving. Applying the brakes, as little as just turning the brake lights on will unlock the torque converter.

I googled a little and didn't find much on this. No idea how to gauge whether it is or isn't out of adjustment. Any ideas on a resource I can look at?

Thanks

 

[gmcman]

Ok. In the first few replies I thought I understood that solenoid would help with the torque converter clutch lockup. Or does the shift kit contain a different fix for the lockup problem?

I think some shift kits may contain the TCC PWM eliminator valve, I don't know. The eliminator valve is what removes the modulated control to the TC clutch, makes it an off/on application. A shift kit will firm up the shifts for the most part.

I googled a little and didn't find much on this. No idea how to gauge whether it is or isn't out of adjustment. Any ideas on a resource I can look at?

Thanks

With the key on, you can tap the brake with your hand and listen for the park lock switch to activate at the shifter. This should happen after the brake lever just begins to move under some light pressure. If the switch clicks with just a feather of a touch then the switch at the brake pedal may need to be adjusted.

But, these platforms have the brake switch set somewhat sensitive so if spring tension is good and the brake lights take a couple pounds of pressure to activate then leave it alone. This helps alot with trailer brakes allowing them to activate quickly. You will know if it's too loose.

Chances are the valve is worn in the valve body, and a simple TCC eliminator should fix this if that's what's happening.

 

[Sparky]

Ok. In the first few replies I thought I understood that solenoid would help with the torque converter clutch lockup. Or does the shift kit contain a different fix for the lockup problem?

It is valve the solenoid activates, not the solenoid itself, that gets changed out and fixed. I went the solenoid route on my old 4L60E first with no change as that wasn't the issue.

 

[6716]

"The purpose of this publication ... is to provide complete information on the theoretical operating characteristics of this transmission."

https://www.dropbox.com/s/q14qjpo7mgqprz2/4L60E.pdf

 

[gmcman]

If I were in your shoes, I would pull the pan, replace filter if you don't know the service history, then add 4 qts and start the engine. Check the level and add as necessary, The pan drop should take 5 qts but it's always good to have 6 on hand.

Don't worry about the filter seal if the filter requires a good tug to remove, just hold on to the new one. You really need to make sure the filter isn't restricted and you have the correct level of fluid.

Yes the dipstick is required to verify fluid level, there are cold hash marks and hot hash marks. Hot is after maybe 15 min of driving, not a brief warmup.

 

[6716]

I did the pan drop and filter change 25k miles ago. I kept leaking / "fixing" the tranmission cooler lines. Then finally did the full replacement on the lines. I ran it under-filled, over-filled, put some in took some out.

It's pretty close to right on according to the dipstick at this point. So I think it's probably not just fluid level, but I could still be wrong on that.

My "codebuster" and shift kit came in the mail yesterday, and it occurs to me I don't really know $&!t about the transmission.

It runs pretty well for the most part, for my daily driver usage. It's when I run it longer / go fishing three hours away that I notice the problems the worst. So I think I'l probably keep studying that shop manual for a while, and read the how-tos here and on offroadtb until I understand each component in the kit and the order they come out / go in.

Hopefully I'll get it done before the cold sets in.

 

[6716]

So this kit comes with Sonnax Pinless Accumulator Pistons (forward, as well as 1-2 and 3-4). Two things I'm trying to figure out ahead of time: How does the pin come out ... and ... do I re-use the OE springs? There are lots of springs in the shift kit, but I read on an LS1 forum that the Transgo upgrade springs (which also shipped with this kit) don't work with the pinless accumulators.

Thanks for all the input, I have learned a ton. I feel readier to tackle this than I thought I would at this point.

 

[Mooseman]

You should contact the seller but IIRC I used the springs that came in the kit. The pins just pull out either by hand or with some pliers. Nothing dramatic.

 

[Sparky]

Pins just pull out. They are just sitting in there for the most part. I used the Transgo springs with the pinless accumulators.

 

[6716]

You should contact the seller but IIRC I used the springs that came in the kit. The pins just pull out either by hand or with some pliers. Nothing dramatic.

Pins just pull out. They are just sitting in there for the most part. I used the Transgo springs with the pinless accumulators.

There are a lot of springs in that orange box!

Did you just pick the best match for what came out?

Is there a spring for the 3-4?

How hard did you whack the check balls in the pin bore to seat them?

Did you do the forward accumulator piston as well? I don't think I have a problem with that.

I have identified the TCC fix parts.

I don't think I'm going to drill the new plate.

And I got three plate gaskets in the package, all with different letter stamps. I suppose I will contact the vendor on that one.

Thanks for all the help.

 

[gmcman]

I have identified the TCC fix parts.

I don't think I'm going to drill the new plate.

Just a fyi...I was recommended to drill my new plate for the TC clutch. This will increase holding power. I will try to dig up the template showing the location and bit size.

 

[Sparky]

Just follow the directions that came in the orange box. You use the springs it says to use. You WILL have springs left over because which springs you use in some areas depends on what exact components you have in your valve body.

And yes, I'd recommend drilling the plate as the instructions say.

The balls don't take a lot to put in place, but you have to seat them and use a punch/hammer to dimple the aluminum to hold them in place. How that is done is in the directions with the Sonnax accumulators IIRC.

I did everything. I had no problems with my trans in my Trailblazer but I just did everything anyway as preventative against something going wrong. Why not while I'm in there?

 

[6716]

Just a fyi...I was recommended to drill my new plate for the TC clutch. This will increase holding power. I will try to dig up the template showing the location and bit size.

Thanks. the template came with the kit, so I'm good on that.

 

[6716]

you have to seat them and use a punch/hammer to dimple the aluminum to hold them in place. How that is done is in the directions with the Sonnax accumulators IIRC.

is this what they mean when they say in the directions "Lightly stake the pin bore after pressing in the balls"?

 

[Sparky]

Correct. That little fold of aluminum from using a larger punch makes sure they don't come loose.

 

[6716]

OK, the vendor customer service dude was sort of helpful. I guess for the 1-2 accumulator I would figure out which sort of pin/piston type I have, and then use the appropriate spring for that with the pinless piston.

I think I'll have to re-use the spring in the 3-4, and I read it is definitely recommended to re-use the spring in the forward accumulator.

As for the pistons, though, the directions say to lubricate. With ATF? Something else?

Thanks

 

[Sparky]

Yeah, ATF or that petroleum jelly that they recommend using to hold the check balls in place while putting stuff back together. Basically something so the O rings aren't going in dry.

 

[6716]

I'm going in!

I dropped the pan and got the filter out once it got back below 90 today. With luck I can get through everything tomorrow so I can get to work on Monday. I'm going over everything one more time tonight in a final study session.

I'm not going to do the servo.

And I'm still on the fence about drilling the plate. Since I'm not doing the servo, there are some plate holes that won't get messed with.

If I only drilled some of the plate holes, the ones at .093" I wonder which, and why.

 

[Mooseman]

I did mine a couple years ago. The only one I regret drilling out was the 1-2 shift to .082 (short). I'd either leave it alone or just drill it out just a tiny little bit but less than .082. I didn't do the servo neither and I'm still all good. I definitely still like the TCC lockup and the other shifts were firmed up perfectly.

 

[6716]

I'm struggling to get the pins out of the accumulator housings.

Now I kinda wish I hadn't put the pliers on the pin in the 3-4, i'd be tempted to re-use the old pin/oiston.

Anyway, now that i have messed up the pins and they have to come out .... is there a trick to it?

some threads say they pretty much come right out, but that is not my experience so far.

 

[Sparky]

Vice grips, wiggle it, pop.

At least that was my experience

 

[Mooseman]

Yep, just twist and pull was my experience.

 

[6716]

Well I got the housing one figured out. I had to drive it out from the back, but I got it. Now to get back under it and get the 3-4.

Forward accumulator came out pretty easily.

I am super wary about the spring change, Might put the stock 3-4 spring back in. The directions on the kit say to put the spring and piston in a way that doesn't make sense. Not that I know what I'm doing or what making sense would be ...

 

[Sparky]

I think I know what you're talking about. It seems reversed from stock and makes you wonder how the heck is this supposed to work... Well, I figured they did the research, not me, so I did what they said and by golly, yeah, it works fine.

 

[6716]

Totally!

The springs for the 1-2 accumulator aren't as long as the stock ones. On that I shrugged and thought "well I guess they are different for a reason."

Ultimately I guess I'm not looking for a "performance" upgrade. I'm not trying to smoke anyone off the line. The truck should run, and I should be able to run on the highway until I get to the woods and then go down the dusty trail 'til I find the fishing hole. But I don't need to chirp on the shifts.

Oh, well, I'll do it their way. I'm super nervous the thing isn't going to go when I have it all back together.

Thanks for the tip.