trans issues

MikesTB

Original poster
Member
Mar 2, 2013
24
I recently changed my trans fluid I used Mobil multi vehicle in my 03 trailblazer and drove about 300 miles and now when its cold and I shift into drive it acts like its in neutral does anyone know what might be happening
 

meerschm

Member
Aug 26, 2012
1,079
looks like that stuff is claimed to be ok for DEXRON III.

GM recommends DEXRON VI

What exactly did you do, pan drop, filter change and fill?
 

MikesTB

Original poster
Member
Mar 2, 2013
24
Yea I dropped the pan and changed the filter it seemed to be doing better smoother shifting it was full synthetic fluid I put in the level is still good
 

meerschm

Member
Aug 26, 2012
1,079
was it acting funny before you changed the fluid?

does it work ok after it warms up a bit?


( I used to live on Shady Lane just north of Dayton-Xenia Road with a Xenia Zip code, small world)
 

MikesTB

Original poster
Member
Mar 2, 2013
24
Yea it was slipping a bit and not shifting when it should, it works perfect when its warmed up
 

gmcman

Member
Dec 12, 2011
4,656
MikesTB said:
I recently changed my trans fluid I used Mobil multi vehicle in my 03 trailblazer and drove about 300 miles and now when its cold and I shift into drive it acts like its in neutral does anyone know what might be happening

Are you checking the fluid with the trans hot, engine idling?
 

MikesTB

Original poster
Member
Mar 2, 2013
24
Yea I check it when its warmed up and the engine is idle it does act like yours was sometimes its just erratic
 

seanpooh

Member
Jan 24, 2012
461
So you dropped the pan and changed filter... did you get the right filter for your pan. Some come with shallow or deep pans where there is a filter specifically for both. Also, the shift cable is right there next to the transmission bolt, double check and see if it was harmed.

Also, when you added fluids back to the tranny, how many quarts did you put in? I could never read the fluid level on the dipstick, I think mine has been over filled for over 50K miles. I think if you drop the pan and change filter, you're suppose to put 5-6 quarts back in.

Oh yeah, there was a cork gasket that came with the filter, did you change out the old and put in the new OR left the old in there and stuck the filter in OR did you leave the old and also put the new...

I'm just asking all these questions since it will help us help you.
 

meerschm

Member
Aug 26, 2012
1,079
I cannot get a reliable hot trans fluid level. reads way too high. I gave up trying to figure out what is wrong. probably some seal leaking someplace inside, but it seems to work just fine for me.

after my pan drop and refill, I put in 5 quarts, then checked level in gear cold, pulled out a bit less than a quart, now it reads full cold on the indicator stick, running in park after running through the gears.

This probably does not help you directly. but out of curiosity, how much fluid did you put in, and what does it read if you check it running cold, first thing in the morning?

if it works fine when warmed up, be glad we are in spring time. :smile:

GMCMAN, what did you figure out?
 

gmcman

Member
Dec 12, 2011
4,656
meerschm said:
I cannot get a reliable hot trans fluid level. reads way too high.

Out of curiosity, did you turn the dipstick over and try the backside? Generally one side will have a pronounced line and the other will be covered in fluid.



meerschm said:
GMCMAN, what did you figure out?

I went in and changed out some parts, seems like the main culprit was likely the separator plate. The check balls had hammered themselves deep into the plate, I will get some pics up later. Apparently this is a common wear item and likely the cause of slippage as these transmissions age. Definitely took care of the hard 1-2 shift.

With the valve body down I changed out the 1-2 and 2-3 accumulator pistons and also the shift solenoids just because the solenoids pop right out.

The vette servo made a big difference and the trans shifts better (for me) than when it was new.

I don't think one thing did the trick by itself aside from the vette servo, but with all these replaced the trans is much, much healthier.
 

meerschm

Member
Aug 26, 2012
1,079
http://gmtnation.com/f23/how-check-transmision-fluid-level-hard-way-5653/

I can see the level fine, but it gets way too high as soon as it warms up. I was worried, and pulled fluid out the indicator tube(dipstick) until it was so low it fell out of TCC lockup.

it will be fun to see your photos.

so advice for MikesTB, : keep an eye on your ten year old tranny, and if you want do do something, consider another pan drop, during which some maintenance items can be replaced.

there are a few helpful threads here and elsewhere on rebuilding/partial replace of pistons, seals, servo, and separator plates.



I was looking at this site, who will be happy to sell you a whole valve body, with servo and separator plate. I actually ordered it, then I figured out I was low on fluid. He had not shipped yet and was nice enough to cancel the order.

http://www.trutechtrans.com/ACDelco-Valve-Body-25075449.html ( and no, I am not connected to this guy in any way)
 

gmcman

Member
Dec 12, 2011
4,656
Come to think of it, WARGAWD had a similar issue and I don't know what became of it, but I noticed there wasn't a splash guard near the base of the dipstick tube on his, mine has one and it's an 02 model. I also thought the dipstick was different but the numbers did jive.

Something to check is make sure the number on your dipstick is the correct part for your vehicle.

I also noticed a lift in one of your pics....yours? :cool: Since you live just over the river from me, if you want to venture into the bowels of the trans, I'll be happy to offer some assistance in replacing the separator plate, a few pistons and a vette servo if you want. On my back it took me 3 hours with a beverage break or two and that was learning a few things as I went along. An air compressor will make things much faster....I had to recharge a battery or two. :biggrin:
 

meerschm

Member
Aug 26, 2012
1,079
I wish.

that lift is at the Ft Belvoir Auto Hobby shop. I am retired Air Force, and they are nice enough to let me use the facility.

bunch of nice guys for an army base. :smile:

Thanks for the offer. for now I think I will just keep an eye on mine. she seems to run just fine, have run up to the catskills of NY and to New Hampshire for a couple ski trips this winter and was satisfied with the performance.

I have a nice air compressor, and have at times looked at buying a lift. I like to use a 3/8 speed handle, even though the regulars laugh at me when i pull it out.
 

MikesTB

Original poster
Member
Mar 2, 2013
24
I matched the filters up when I got the old one out to make sure I got the right one the new gasket was rubber and I made sure none of the old cork gasket got into the filter I added 6 qt it was a bit over when hot but it terribly overcooked I cleaned the mag pan and mating surfaces with brake cleen let dry and reinstalled it hasn't acted up at all today I have been reading both sides of the stick cause one side will be double the other
 

gmcman

Member
Dec 12, 2011
4,656
Sounds good, if it ever starts acting up let me know.

I thought I posted this but not sure, here's the seperator plate that I removed at about 165K miles. One of the check balls actually pounded through the plate, this is where the plate wears under normal operation, also the new pieces I installed...vette servo not shown.
 

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meerschm

Member
Aug 26, 2012
1,079
MikesTB said:
I matched the filters up when I got the old one out to make sure I got the right one the new gasket was rubber and I made sure none of the old cork gasket got into the filter I added 6 qt it was a bit over when hot but it terribly overcooked I cleaned the mag pan and mating surfaces with brake cleen let dry and reinstalled it hasn't acted up at all today I have been reading both sides of the stick cause one side will be double the other

you mentioned a mag pan, is your pan aftermarket? the original one is steel, with a magnet inside.

the original is spec'd to need five quarts for a pan drop change. I am curious what yours reads first thing in the morning when it is cold. (running in park after going through the gears, don't have to move the car)

hope it keeps working fine for you. how many miles do you have?
 

MikesTB

Original poster
Member
Mar 2, 2013
24
No its stock pan I cleaned the mag in the pan it has 219000mi
I also changed the seals on the trans cooler on the radiator they were leaking a bit
 

meerschm

Member
Aug 26, 2012
1,079
impressive.

how much longer to you plan to keep it?
 

MikesTB

Original poster
Member
Mar 2, 2013
24
Until the wheels fall off then I will put them back on and drive it some more hahaha
 

Tarnished

Member
Dec 3, 2011
74
Mine acted like that for about a week after I serviced it and changed out the plastic pistons, stock servo, filter.. etc.
Mine was acting up because I installed a pan that held more quarts, and my filter fell out of the tube.
It seems my procrastination on changing the filter seal was the culprit. The filter fell out and was just floating loose in the tube. On hills and acceleration, it fluid starved.. and then finally received fluid.. and drove erratically.
And that seal is a nasty one to change.
 

MikesTB

Original poster
Member
Mar 2, 2013
24
Oh I know all about that seal I was going to leave it in there but I had already ruined it
 

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