Bill's Build (with comments, questions, and Conundrums)

[ProTouring442]

So it's the same quadrant but the removable gate is what you replaced? Where did you find the replacement gate? Almost looks like the original gate could be modified and the travel be farther?

It is my understanding that the gate is called the shift quadrant. I don't know why, or even if I am correct. That's just what we always called it.

The detents on the new piece are in slightly different places as well.

The new part is out of a newer GM, column shift vehicle with overdrive (4-speed, 4L60E/700R4). It has the number 5994 stamped on it.

I still have to play a bit with the linkage, but I am close to having all 4 gears.

[ProTouring442]

Well....


I Drove It!!!!!!



But I have a transmission problem. Argh! It doesn't want to shift out of first at part throttle, and at WOT it drops back into first, even when it was in third.


Hmmm......

[243]

Awesome work and I know it's a great feeling driving it, sorry to hear about the trans issue.

[ShawnQ]

Trans possibly a speed sensor issue? Lone pressure?

Or do you think it's internal?

Congrats on driving it!

[ProTouring442]

Trans possibly a speed sensor issue? Lone pressure?

Or do you think it's internal?

Congrats on driving it!

Don't know yet... It will run up through the gears under part throttle, but always drops back to 1st at WOT. I am awaiting a scantool, and then I will see what the trans is being told to do.

I don't think it's the VSS as I have speedometer readings as it accelerates. In the end, it's just a growing pain, but at the moment, it really hurts!

[lobie]

I would speak with who ever programmed the ECM. Sounds like the shift settings have been tweaked. There are several tables that control the shifting based on TP, MAP, Speed, Temp, etc.

Congrats on the drive. One big hurdle to get over.

[Jeepin Jeff]

Could it have something to do with the 4 low wire to the ECU being grounded when it shouldnt be? If I remember right that wire needs to be grounded only when you are in 4 low or you have all kinds of shifting problems. I'm not sure what it would do if grounded all the time but it could cause shifting issues I would think. Just something to consider.
You will get it worked out, I'm sure.

Jeff

[ProTouring442]

Actually, after a few more test drives, it looks as though second is missing. It shifts from first to third, and from third to first. This looks to be a 2/4 servo (it's actually two servos in one, with two pistons and two different fluid sources) or a 2/4 band issue. I'll have to wait until Tuesday when my HPTuners scan tool software comes in, but I think I will find that when I engage second gear with the scanner, it will stay in first. It could be a valve body issue, or it could be a servo issue, but it's likely not a "transmission" issue (i.e. a problem with the clutches or other mechanical issues).

[ShawnQ]

On your harness, ECM X1 connector, pin #2 & 3, 4wd signal and axle signal, are they present?

What about pin #71 & 72? Where are they going? These are Vss related.

I also remembered you rebuilt/freshened your transmission, didnt you? I have a hard time believing it is bad with low mileage like yours had. Maybe something got in the lines and plugged up a valve?

Let us know what you find.

Also, you used a PSI harness...did they tune the ECM also?

[ProTouring442]

On your harness, ECM X1 connector, pin #2 & 3, 4wd signal and axle signal, are they present?

Is this the 4wd low signal? If so, no I don't have it, but that shouldn't stop the transmission from shifting properly, though it likely will set a code in 4wd low for a bad VSS signal.

What about pin #71 & 72? Where are they going? These are Vss related.

The VSS is finctioning as I have a CAN/BUS speedometer, and that works no problem.

I also remembered you rebuilt/freshened your transmission, didnt you? I have a hard time believing it is bad with low mileage like yours had. Maybe something got in the lines and plugged up a valve?

I don't think the trans is bad, though it's certainly possible I cut a seal or miss-assembled something in the servo. A bunch of research seems to indicate that my problem is servo/ 2/4 band related. If it were a solenoid, it would drop into neutral when it attempted to shift to 2nd. Instead, it just holds in 1st until I lift a little, then shifts straight to 3rd. On WOT, instead of dropping back to 2nd (or neutral, if the solenoid were bad), it goes all the way back to 1st. Since the only real difference between 1st and 2nd gear is the application of the band (and the band is new), it has to be a vavle body/servo issue, with the servo being more likely.

I'll definitely know more once the scan tool deal is here (Tuesday), and I'll let everyone know how it goes.


You can see why I think it's a servo/valve body issue with the chart posted here: http://autoforums.carjunky.com/Automoti ... d_P135972/

Also, you used a PSI harness...did they tune the ECM also?

Yes, they tuned the ECM and TCM. I had a problem with the ECM, and they took care of that with no questions.

[ProTouring442]

Took it for a road test this afternoon with the scantool hooked up. When I forced the transmission into 2nd with the scantool, the transmission stays in 1st. Shift it to 3rd, and the transmission shifts into 3rd. Force the shift to 4th, and it stays in 3rd.

There are only 2 sets of clutches involved in all 4 gears. Since it goes into gear, I know that the forward clutches are operating. Since it goes into 3rd, I know that the 3-4 clutches are functioning. With 2nd and 4th missing, I know that the band isn't engaging. This will be a servo or valve body issue, most likely a servo issue. I'll pull the servo and the pan and see what's up. I'll let you know as soon as I figure it out.

[ShawnQ]

Servos are fairly easy to get to aren't they? And just a simple electrical connection?

[ProTouring442]

Servos are fairly easy to get to aren't they? And just a simple electrical connection?

The servo is a hydraulic unit, no electrical connections. It pushes on the band to engage. Likely, I either assembled it incorrectly, or manage to invert or cut a seal.

[ProTouring442]

The verdict is in, and it was my fault!

Ended up pulling the pan and valve body to discover that while assembling the transmission, I accidentally disengaged the band from it's retaining pin. In driving it, the band had walked a good 3/4" out of place, but no damage was done. I was able to jiggle/wiggle/tap the band back into its proper position and re-anchor it. Reassembly has commenced, but I will have to get a new pan gasket and filter, and a new Servo O-ring (not to mention more transmission fluid) before I can button it all up.

Happy Thanksgiving everyone!

[243]

Same to you!

Good to hear your found the problem, impressive that you can rebuild and automatic, that and setting up a differential are the two remaining tasks in my bucket list as far as vehicles is concerned.

[ShawnQ]

Nice!
I'm automatic-illiterate

[Jeepin Jeff]

Good work!

[ProTouring442]

And we have Jeepage! Finally got the trans back together, and we now have all 4 gears!

Still a fair bit more to be done, but the thing moves under its own power, drives well, shifts well, etc.

[Tatsadasayago]

W00T!

[unlimitedTJrubi]

New here, I have just finished reading all eight pages of your build so far. Impressive build to date, your skills, talent, and knowledge are amazing. When we take hold of our Wagoneer next weekend we hope to have something decent to drive for a while before we begin some sort of a driver project on it. I love all the little critters you have found along the way too. and I was in high hopes that the surgery would deplete your migraines, I hope that you and your doctors find some sort of relief soon.
Dan