2003 sierra transmission wont shift

[bmxjunkie]

I have a 2003 sierra that works in 1st in 2nd, but it wont work in 3rd and drive, its like it goes into neutral when it gets up to the speed..thats even with it engaged in the drive function..Is this just an electrical problem or is my transmission sacked?.. Is there anyone that could help me with this?I'm a single parent and any help would be greatly appreciated

 

[Molson02536]

I have a 2003 sierra that works in 1st in 2nd, but it wont work in 3rd and drive, its like it goes into neutral when it gets up to the speed..thats even with it engaged in the drive function..Is this just an electrical problem or is my transmission sacked?.. Is there anyone that could help me with this?I'm a single parent and any help would be greatly appreciated

Before guessing at transmission problems, check the fluid level (car warmed up, engine running in Park on level ground) and have the PCM scanned for trouble codes FIRST. Trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

If your transmission is starting from 1st and shifts to 2nd, with No 3rd or 4th gear: “3-4” clutches are worn out, Remove & Repair (or Rebuild). The car is safe to drive (in 2) until you can get it fixed, also put a line pressure gauge (or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure.

Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a 0.490" boost valve or a 0.500" boost valve for a more aggressive shift (easy fix in pan).

Here are some of the things i have done to my 4L60E on my Jimmy:

The reverse boost valve and sleeve in the pump should be replaced every 40,000 miles (65,000km) to avoid damage to the transmission. Damage can occur when wear in the boost sleeve causes insufficient line pressure in reverse. Many major repairs of the 4L60E at around 50,000 plus miles are because of the boost valve and sleeve.

The valve and sleeve can be replaced easily during a routine service of the transmission for around $50. This should be considered a necessary procedure if you are hard or have lots of stop and go with extra wight. Oversized (0.490" versus the stock 0.470" or 0.420") reverse boost valves are available that provide a moderate increase in pressure, and are a good addition to any 4L60E.

I also remove and discard the 3/4 load release spring assemblies (5 small rectangular spring assemblies installed into the input housing, on the outside of the clutch pack). This really improves the 2-3 shift, and last which is the easiest was swap out the servos with Corvette servos. It takes about 45 min from start to finish and that's including the clean up time and you don't even have to drop the transmission pan to swap it out.

Good luck and hope it's a simple A shift solenoid that has gone bad or better yet, just a faulty wire leads to the solenoid at the transmission clip (Common for connection to go bad). You can do the other upgrades while they have the transmission pan dropped. Most transmission shop can test the transmission performance with a scanner to determine if it's the solenoid or something else other mechanical that is causing your transmission issues, and remember. Call around, all transmission shops are not alike and some would rather have you install a re-manufactured transmission then spend $300.00 for the repair and upgraded parts.

 

[Molson02536]

4l60e

Keep me posted on how you make out with getting your transmission repaired, hate seeing transmission shops take advantage of people and being told that they need a new transmission over a simple fix. You should get a DTC code P0753, "Shift Solenoid "A" -- Electrical." When a shift solenoid goes bad, the transmission goes into a "limp-home" mode which is the 2-3 shift only (and that one shift seems to be kind of harsh). The shift solenoid at the dealer AC Delco # 10478131 $19.18.

You have to take the transmission pan down to reach the solenoid so you also need the supplies to change the fluid and tranny filter while your in there. It helps to have a very large drip pan so you can catch all of the fluid, there is no drain-plug.

You just have to remove the bolts and let the fluid spill out. There are two identical shift solenoids ('A' 1-2 shift and 'B' 2-3 shift). Pull them both and be sure to take out the retainer clips on the bottom and then disconnect the wiring harness or you can keep both solenoid in place to test them.

With wires, jumped them off the battery to locate the bad one. The good one will clicked the bad one will do nothing at all and easy to spot!! The filter pulls out without any tools and in the hole where the filter comes out is a metal/rubber seal. Take that out with a screwdriver carefully so you dont nick the tranny case. Insert the new seal and filter.

The new solenoid goes back in the same way it came out, cleaned the gasket surfaces on the pan and tranny and bolted everything back in place. It takes about 6-7 quarts of Dextron III fluid to refill through the dipstick-tube if you change the filter.

Started the motor and put the tranny in and out of all the gears several times to "bleed" everything down there. Mission accomplished! If it works perfectly, just say "Special thanks to Molson who gave me guidence throughout this project! You Rule Molson ! ! ! !"

1= a solenoid or 1-2 solenoid 2= b solenoid or 2-3 solenoid 3= pwm tcc solenoid 4= 3-2 control solenoid 5= epc/pcs solenoid and you DON'T have to drop the valve body from the transmission. It takes about 2 min to remove and disconnect the wire leads and replace and reattach the new wire leads.

http://i110.photobucket.com/albums/n97/Vinceflt/SOLENOIDID.jpg

http://www.compnine.com/index.php?u...delid=7036&capuid=1&majorgroup=04&grouptype=B

 

[gearbangin]

03 SIERRA wont shift 1st to 2nd unless I let off gas!!

My 03 Sierra will not shift from 1st to 2nd unless I let off the gas. all other gears are fine. No DTC's and will not shift at all manually only in drive. If you know anything about this please please let me know I really do not want to fork out the money for a new trans I have only had the vehicle for a month and have spent every last dollar!!

 

[Molson02536]

My 03 Sierra will not shift from 1st to 2nd unless I let off the gas. all other gears are fine. No DTC's and will not shift at all manually only in drive. If you know anything about this please please let me know I really do not want to fork out the money for a new trans I have only had the vehicle for a month and have spent every last dollar!!

Start with the simple and check the fuse to your ECM and Transmission in the fuse box. Common issues with Transmission not shifting automatically, only manually. Swap in a known-good PCM, check wiring, check other sensors such as VSS and TPS.

Most transmission shop will check the transmission free of charge to pin point what issues need to be addressed.

Good luck and keep us posted.

Molson02536

 

[gearbangin]

Thanks Molson! do you mean the throttle position sensor? also I forgot to mention that it will not shift manually at all it starts itself in first in 1 2 and 3.

 

[Molson02536]

Thanks Molson! do you mean the throttle position sensor? also I forgot to mention that it will not shift manually at all it starts itself in first in 1 2 and 3.

If there is No 1st or 4th available and the trans shifts 2nd to 3rd by itself in D or OD and locks the converter.

The ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.

If the SIERRA goes into gear but feels very sluggish like the brakes are dragging, but it will roll easily (starts out in 4th gear), and if you manually shift to 2 to get it moving.

Once it's moving you put it back in OD and the Sierra shifts 3rd to 4th on its own and locks the converter at the appropriate time: ShiftB solenoid failed: Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM

Keep me posted and hope its a simple wire harness issue. Inspect the wire harness at the transmission on the passenger side for any signs of corrosion at the connection. If there is corrosion, clean up the connection or replace if it can not be cleaned up for a good connection.

Keep us posted and keep up the great work

Molson 02536

 

[gearbangin]

Molson I should also mention the sierra does not have an OD only a D. It obviously has overdrive but only 1 2 3 D. It will not manually shift at all. In any of these it still starts itself in 1st gear. So I just leave it in D. There is no shake or shudder or slip.Good power but will not shift into 2nd gear until I get it between 2500-3000 rpms and then let off the gas for a bit. Then it slowly shifts into 2nd reluctantly. Against your better judgement I had the trans flushed today and it is still the exact same. Later this week I will swap TPS first then have the shop do the line gauge test. I will also inspect wires harness and fuses. Didnt really see any fuse for the trans but I will look again I heard it shares the same fuse as the O2 sensors? I will keep ya posted thanks again Molson

 

[Molson02536]

Molson I should also mention the sierra does not have an OD only a D. It obviously has overdrive but only 1 2 3 D. It will not manually shift at all. In any of these it still starts itself in 1st gear. So I just leave it in D. There is no shake or shudder or slip.Good power but will not shift into 2nd gear until I get it between 2500-3000 rpms and then let off the gas for a bit. Then it slowly shifts into 2nd reluctantly. Against your better judgement I had the trans flushed today and it is still the exact same. Later this week I will swap TPS first then have the shop do the line gauge test. I will also inspect wires harness and fuses. Didnt really see any fuse for the trans but I will look again I heard it shares the same fuse as the O2 sensors? I will keep ya posted thanks again Molson

If the TPS is working good with no issues, the other thing i can cause this issues would be a 1-2 accumulator piston cracked or stuck cocked in the bore. Check the yellow spring inside the accumulator housing for breakage.

Also, if the accumulator housing walls are scored, the housing must be replaced ans is a easy fix in the pan.

Keep us posted.

Molson02536

 

[gearbangin]

03 SIERRA wont shift out of first until I let off gas

UPDATE: Just got back from trans shop. Turns out I dont have 2nd at all. The tech drove it and sure thing when we got going down the highway it only shifted
2 more times. going down the highway in 4th gear i can drop it in 3 and it will go. I feel kinda dumb that I didnt notice before. Anyways he says 1300 if I take it out and he rebuilds it or 1800 if he does it all. I will keep this thread posted. Thanks

 

[Molson02536]

UPDATE: Just got back from trans shop. Turns out I dont have 2nd at all. The tech drove it and sure thing when we got going down the highway it only shifted
2 more times. going down the highway in 4th gear i can drop it in 3 and it will go. I feel kinda dumb that I didnt notice before. Anyways he says 1300 if I take it out and he rebuilds it or 1800 if he does it all. I will keep this thread posted. Thanks

Still sound like a ShiftA Solenoid has gone bad. That would give you a 2nd gear start and 3rd gear with overdrive. The transmission will shift from 2nd to 3rd with the converter locking up making it seam like it has 3 gears.

Very simple fix when the pan is dropped, if there is a issue with the transmission slipping or band failure. The color of your transmission fluid should be dark and burnt in colour. A good transmission will have a bright red colour to it with he smell of being burnt.

Have a second transmission shop inspect your Sierra and ask him what he think about the shiftA Solenoid being bad if you dont have 1st or 4th gear but have 2nd and 3rd with converter lock up.

Sorry to say, transmission issues are easy money makers when people are told to replace the whole transmission rather then to fix a simple fix that may seam to be a major major issue.

Good luck and keep us posted.

Molson02536

 

[gearbangin]

The fluid was a little dark in color. I didnt smell anything burnt but my buddy said he did. I'm definitely starting out in 1st. gear. almost 3000rpms at 20 mph. And then let off the gas at 2500-3000 and it will shift to 3rd. Having him come over after work again to scan so we can watch the shifts. But Im almost positive that I blew out 2nd gear. (Happened while I was playing in the snow) I am taking the trans out myself soon and I will drop the pan and jump test the solenoids as my first line of action. I have dual exhaust and its ran on the passenger side so at least I have that going for me I dont have to take that off. I will keep my findings updated Thanks

 

[gearbangin]

Quick update on my 03 Sierra. I purchased a used 4l60e from a guy here in town who rolled his truck for 550$. I am going to put corvette servos and a new boost valve in before installing. I will keep you all posted