Can't get rid of harsh 1-2 shift in 4l60e

billr

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Sorry. I can't open that DOCX format. Can you send it as PDF?
 

rhino

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Try this one.
 

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  • 1994_1996 4L60e swap info.pdf
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billr

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Well, I read that and understand why there is some confusion about when PWM started. The originals had on/off control; of the TCC, and they stamped "PWM" on the case when TCC control was changed to PWM. I think I read this in the ATSG manual, too, but ignored it because we are focused on the shifting. I still feel the important controls for shifting, the PCS and two solenoids, have always been PWM; regardless of how the trans case is marked. I am certainly no expert here, may be wrong. Read everything you can find on the PWM subject, hope to find a general agreement in most info.

That Valvoline ATF is a DEX6 formulation, not suitable for my "Hail Mary" try of DEX3.

I may be absent/slow here for a while. My wife and I are both sick with flu.
 

rhino

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billr,
I'm sorry you two are under the weather, my wife and I have managed to steer clear of sickness the last couple of years. This is in spite of the rest of our family and their families coming down with COVID, some of them twice! Don't worry about responding, I have lots of work to do and numbers to get.

But if you could explain your comment on Valvoline Max Life. Are you saying you don't think it's a suitable oil and I should try something else?

Dave
 

billr

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The Valvoline is probably a great DEX6 ATF, but some older trans designs don't work as well with DEX6 as they do with the DEX3 they were designed for. I'm sure the DEX6 is touted to have all the performance benefits of DEX3 and more; but I have heard that is not always true Like I said, changing to DEX3 is a "Hail Mary" play and probably won't work, but you could leave the DEX3 in there and save the DEX6 for future use, if it is reasonably clean coming out of the trans.
 

bp042665

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ok the pwm came into effect late 96 early 97 as for the max life it is fine in this 94 trans if they build it like i do the are using raybestos or borg warner clutches and they like dex IV or dex III we need to see what the pcs amp is to make sure it is working right
 

rhino

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I believe he did use Raybestos frictions and measuring resistance/current on the PCS circuit is on my list. Thanks for the comments.

Dave
 

rhino

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Well, it's been awhile. This should be the last post/discussion on this problem.

Since the last post, I measured PCS resistance, the manual quotes 3.5 to 4.6 ohms and I get 5.0 ohms, but I measured from the PCM connector which added the resistance of extra wire and the trans connector. I think my number is in the ball park. Trans connector is almost impossible to get a hand on.

I connected a gauge to the trans test port and saw about 60-70psi at idle in park or drive and 115-120psi in reverse. About 90psi at a very low load 1-2 shift with a 10psi dip just before the actual shift. Medium load shift was about 120psi with 10psi dip. Both of these tests produced hard shifts and firm shifts and also with or without the dip. High load, WOT, tests showed LP at about 210psi at 5400rpm in 1st gear at the programmed shift point with tire chirping hard shift. I did this test twice with the same results.

The next day, 6/10, I drove it to town and every shift was a nice firm shift, just perfect. And every shift since then has been the same, yet a high load, high rpm shift is still hard-just the way I want it. I didn't adjust anything, replace anything and the only unusual condition involved was the two WOT runs where I just held it to the floor until the PCM shifted to 2nd. Kind of scary because I don't drive like that on a steady basis. Having something mechanical "fix" itself is usually worrisome, But I'll take it.

So, I want to thank you for your help and perseverance with my issue. Maybe the trans controls are similar to the engine controls in that they will do a certain amount of "learning" as the car is driven, makes a good story even if it's not true.

Dave
 

rhino

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Your stuck valve suggestion holds water, especially if one or more have been sleeved. Is Lube Gard a brand name or generic name for a special lube? I will look in parts houses tomorrow. Thank you both (bpo42664 and billr) for that tip.

Dave
 

grcauto

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Your stuck valve suggestion holds water, especially if one or more have been sleeved. Is Lube Gard a brand name or generic name for a special lube? I will look in parts houses tomorrow. Thank you both (bpo42664 and billr) for that tip.

Dave
You would do well with this
 

billr

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Lube Gard is a brand name for transmission fluid additives, and comes in several different formulations tailored for different trans make/model. There are competitor (equivalents?) to Lube Gard, but the LG brand has been specifically recommended by a couple of trans experts here that I trust. The LG is somewhat of a "Hail Mary" play, the "mechanic in a can", but I feel it is a worthwhile Hail Mary...
 

grcauto

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Lube Gard is a brand name for transmission fluid additives, and comes in several different formulations tailored for different trans make/model. There are competitor (equivalents?) to Lube Gard, but the LG brand has been specifically recommended by a couple of trans experts here that I trust. The LG is somewhat of a "Hail Mary" play, the "mechanic in a can", but I feel it is a worthwhile Hail Mary...
Yeah. There are several good ones. Lucas makes good stuff as well.
 
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