Hi all I have a 2007 H3 i bought new.. Ive babied this vehicle since new its a garage queen.. it just turned 41k miles and I noticed other day the transmission was slipping all over the place.. it just started doing it all of a sudden and when I drove it the 2nd day it was worse.. so i put it back in the garage.. Am I really in need of a new tranny .. this sucks only 41k miles Im dissapointed.. the fluid is filled to proper level and is Not black or brown.. its red but there is some discoloration not bright ruby red,. little dirty red.. Ive never changed the fluid... I know that some vehicles can have sensors and electronics that can go bad that can cause the tranny to not shift right.. is there anything I should look at before I take it in and have a new tranny put in.. and also I see that there is places online where you can buy a new OEM ( not rebuilt ) tranny.. is there any dissadvantage to buying a new one over rebuilding your old one.. ? any help on here is greatly appreciated.. Bruce

 

You can try the old change the Trans Fluid and Filter to see if it helps, and inspect the pan for metal or grit when you do. You could get lucky for a while. Unfortunately shtuff happens. Your Trans should go more miles, but any man made part/machine can be defective or just decide to toast itself. Your 07 Trans is controlled by the PCM. You could check the wire harness to the Trans for compromise, fraying, worn wire grounding out, cracked insulation etc...

I would never buy a new replacement. How long did your first new one last? I look at a rebuild as the opportunity to make it better than brand new by using some much higher quality aftermarket stuff, like a Beast SunShell as they do not break, not the Sonnax SmartShell Heavy Duty Reaction Shell (which is still an improvement over OEM, but not as good). I would include some Sonnax stuff, just depends on your budget.

Thoughts:
Heavy duty wide band for maximum hold in 2nd and 4th gear with the Corvette servo instead of a Sonnax super servo.
For Fourth (OD) the Sonnax Dual Piston servo.

These are some great sources of info on that topic if you keep in mind they are Sonnax sales pitched as well:
4L60E Performance & Heavy-Duty Transmission Build Guides

Building the Killer 4L60E

Good luck and let us know what happens.

 

Your fluid is 18 years old...

May be time for a change.

 

 

I used this SEAFOAM based on reviews. I poured entire bottle into the Transmission , Drove 50 miles . Came back let fluid settle & cool down.
Then using a electric siphon drained out the TRANNY FLUID contents in the pan
Then I added about 4 oz of the 'sea foam trans tune' from 2nd can that I bought, then I Topped off with ATF+4 Synthetc Tran fluid & 1/2 bottle of Lucas anti slip transmission stabilizer
and did another 50 miles test run.
My H3 shifts like brand new !! I’m happy because I thought I was going for a tranny rebuild . But SeaFoam dodged that bullet Highly Recommend

 

Just barely old enough to vote.

 

yes I did inquire about that about 9 months ago at the local Chevy dealer and he said no do not do that its too late and too many years have passed,... that it would wreck the tranny..

 

Ski Dive..... well being the tranny is up for a rebuild I guess I can try this .. I have nothing to loose.. how many total miles have you put on since this? I think I will try this before I take it in to be rebuilt see what happens.. Thanks..

 

Doc Olds thank you for all the informative and detailed information.. Your a huge help. Let me digest all this.. and no Im not going to buy a new OEM replacement.. Ill rebuild mine with the suggested better parts.. I received a quote of $3700 at local AAmco for the rebuild.. I dont know if that is typical or not.. but I can buy the better parts and have them use them instead when I go that route I may have some more questions after digesting all this for you about which and all parts I should buy.. Thank you again for all the help bruce

 

My father ran dealerships back in the day, I would not take advice from any local dealer about much since they just want your business and don't really care if whatever you want to do might solve a problem. They want to sell you a new AT so if you solve a problem, they loose a sale.

I have used the Seafoam Trans Tune and it will clean out some crud and varnish. So long as you change the fluid and filter after running it a bit, it can help.