2003 trailblazer trans not shifting corectly and reverse not working

jigfeett

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#1
Please fill out the following to ask a question.

MAKE:chevrolet
MODEL:trailblazer LT
YEAR:2003
MILES:155500
ENGINE:4.0
DESCRIBE ISSUE....while driving made a bunch of noise and seemed to still go,ie. move forward.
Drove home but shifting of gears the engine revved to over 4K and had to feather throttle to get it to shift.
Reverse does not work
When test driving found that it appears to only have a couple of the 4 forward gears.

My question What years of transmission interchange to this 2003 model year?

Thanks
 

EricC

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#2
No reverse, no second, no fourth gears. Sounds like a stripped reaction sun shell. Salvage yards keep cross reference books as far as the interchange question.
 

jigfeett

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#6
Update, I bought the book and kit to rebuild the 4l60e transmission updates to come
 

EricC

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#7
Update, I bought the book and kit to rebuild the 4l60e transmission updates to come
Make sure you flush the cooler and lines. I'll assume you're replacing the torque converter? Most specialty tools you can fabricate from common materials. You may have to pick up or borrow a couple of things.
 

nickb2

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#8
I am just curious, what book? The gm one or the haynes one?https://www.amazon.com/ATSG-4L60E-4...coding=UTF8&psc=1&refRID=HFWNYH6PMHG05XPAM04W

That link is for the update book.

I hope you bought this one, it is very well documented. https://www.amazon.com/ATSG-4L60E-T...rd_wg=q4yOt&psc=1&refRID=NMKXTT6JBAEQB5WEA1GE

I have a few of the haynes ones, I find them very valuable. I think your very courageous and applaud you for attempting this. You will get alot of satisfaction from doing this yourself.

I don't recall ever seeing a 4.0l in a GM such as this, so I am going to assume you have the 4.2l.

As for the interchangem you did not mention if this was a 4x4 or 2x4. The internals are almost identical in regards to the clutch packs, sun gear etc,


Anyway, I thought I would provide a overhaul from alldata, may compliment the haynes (I assume) one you astutely bought. See the ace 0 pdf. You could download that to your smart phone as a quick reference in case you mess a page or to of that sweet book.

BTW, @jordanr I am surprised with the new update of the site, takes bigger attachments. That is also sweet.
 

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nickb2

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#9
Oh, forgot to mention. This is a must, buy a tub of Vaseline. Cheaper than the assembly stuff ppl are always trying to push. Ask any trans guy, vaseline is the best.

Old mechanics joke, if you have some left over, you not doing well with the wife. :oops:
 
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#11
Kids 1993 Bravada has this problem contacts in his neutral safety switch or whatever they call this now contacts were all corroded., took the switch apart and polished them to a mirror finish. Also would not go into torque converter lockup, brake switch had dirty contacts.

Other problems are in the connector with corroded terminals. What does your fluid look like, if burnt, would have clutch slipping problems. He was told by a shop needed a new transmission for around 4000 bucks, can you get it home? Governor, vacuum modulator, and that complicated control valve is all history, replaced by a few solenoid valves and a 89 cent microcontroller. Also a Vss sensor, just a tiny bar magnet with a few turns or wire wrapped around it, but yet the prices skyrocketed. Another area with dirty connector contacts.

His fluid was clean, about the only thing that gear lever does is drop a pawl in a gear when parked, rest of it is all electronics. Use to have a separate transmission module, now most of the is part of the ECU, if a wire shorts out, can burn up a transistor driver, so just cannot replace the module. Happened to another friend of mine, completely sealed, 1,300 bucks for a new one for a VW.
 

EricC

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#12
Kids 1993 Bravada has this problem contacts in his neutral safety switch or whatever they call this now contacts were all corroded., took the switch apart and polished them to a mirror finish. Also would not go into torque converter lockup, brake switch had dirty contacts.

Other problems are in the connector with corroded terminals. What does your fluid look like, if burnt, would have clutch slipping problems. He was told by a shop needed a new transmission for around 4000 bucks, can you get it home? Governor, vacuum modulator, and that complicated control valve is all history, replaced by a few solenoid valves and a 89 cent microcontroller. Also a Vss sensor, just a tiny bar magnet with a few turns or wire wrapped around it, but yet the prices skyrocketed. Another area with dirty connector contacts.

His fluid was clean, about the only thing that gear lever does is drop a pawl in a gear when parked, rest of it is all electronics. Use to have a separate transmission module, now most of the is part of the ECU, if a wire shorts out, can burn up a transistor driver, so just cannot replace the module. Happened to another friend of mine, completely sealed, 1,300 bucks for a new one for a VW.
The OP's Trailblazer has no reverse. Reverse doesn't use electrical inputs in a 4L60E, it's all mechanical.
 
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#13
Sure is mechanical, has planetary gears clutches, hydraulic pump, torque converter lockup, but is electronically controlled, least before OBD II, electronics use a microcontroller with a PROM, code was burnt in. Then started using EEPROM where charge could be lost due to leakage, loosing code, also could replace the driving transistors. Yet another problem, if the starting voltage dropped below 8.5 volts, would not get that all important power on reset voltage, so reading code was random. So have to take it to a dealer to have it reflashed.

Ford had the AXOD, 100% mechanical, but then came out with the AXODE, E stands for electronically controlled.

Really like my 2017 Hyundai Elantra Limited, can hook it up to my WiFi router and reflash all four BCM circuits, even updated the AT code. Does all except the ECU, for whatever strange reason, only a dealer can do this.
 

EricC

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Sure is mechanical, has planetary gears clutches, hydraulic pump, torque converter lockup, but is electronically controlled, least before OBD II, electronics use a microcontroller with a PROM, code was burnt in. Then started using EEPROM where charge could be lost due to leakage, loosing code, also could replace the driving transistors. Yet another problem, if the starting voltage dropped below 8.5 volts, would not get that all important power on reset voltage, so reading code was random. So have to take it to a dealer to have it reflashed.

Ford had the AXOD, 100% mechanical, but then came out with the AXODE, E stands for electronically controlled.

Really like my 2017 Hyundai Elantra Limited, can hook it up to my WiFi router and reflash all four BCM circuits, even updated the AT code. Does all except the ECU, for whatever strange reason, only a dealer can do this.
No, reverse is not electronically controlled. It Is Purely Mechanical..
 

bp042665

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#15
if you unplug the transmission you will have reverse and third gear in the 4L60E trust me i have a transmission shop so if no reverse or 2nd & 4Th its the sun shell