NEED HELP 2006 chevy trailblazer tran

TollKeeper

Well-Known Member
I can tell you that the first thing everyone is going to ask, in completely random, as they come across my mind, order, they are....

  1. Is the tranny fluid full
  2. Mileage of truck
  3. Is the check engine light on
  4. If the light is on, what are the codes
  5. Whens the last time you had the tranny serviced
  6. When was the last time it was serviced prior to that
  7. What is the condition of the transmission fluid (color and smell)
  8. Do you have a auxiliary transmission cooler
  9. What is your engine temp gauge at when it acts up
 
OP
OP
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skip g

New Member
the trans is full ,truck has 240,00 miles ,check eng light is not on , has no codes ,just got the truck 6 mouths ago ,the trans fluid was dark brown and a old smell to it.put new filter and a&b shilt solenoids thanks
 

Reprise

Lifetime VIP Supporter
Additional questions (and I'm not a pro mechanic or trans rebuilder)

- Was this happening before you changed the fluid / filter / solenoids (in other words, were you trying to fix an existing problem) ?

- When you say "going in / out of high gear"... is it
A) Dropping out of lockup back into 4th (about 200rpm change, either way) ?​
Or​
B) Dropping from 4th down to 3rd (probably 500rpm or more increase in engine speed) ?​
(Note: We'll assume that this is happening at steady throttle / cruise (not 'cruise control') -- if it's happening when you increase throttle more than a hair, it's normal to drop out of lockup and/or down a gear, depending on how much additional throttle you applied.)


If 'A' sounds like what you're experiencing (lockup <> 4th), I'd guess that your TCC valve has probably worn the bore / cavity it sits in. Either install an oversized valve & a sleeve insert, or replace the valve body outright with a rebuilt or new. I'll spare the long explanation of 'why this happens'; you can find the info online. Mileage is a factor here, just like the other issue below (although when it happens, it's usually well below 240K).

The other possibility here is that your torque converter itself could have an issue. They can be replaced without fully removing the trans from the car, but it's a bear of a job to do it on your garage floor, without a lift. The trans has to be unbolted from the engine and moved backward in order to replace it.



If it's the second scenario, 'B' (4th to 3rd, back & forth)... that's not very common. Could be any number of things, but you will likely need to rebuild or replace the trans. The 4L60 is a good unit, but at 240K, it's given good service, and one shouldn't feel like it wore out prematurely, at that mileage.

Personally, even if it's the valve body or torque converter... if you plan on keeping the truck, I'd put some money aside for a replacement.

As a test, you can try driving with the trans in '3', vs. D. Your gas mileage will take a hit, but you'll save additional wear on the clutches (if you're going back / forth between 4th <> 3rd), or you'll save (further) wear on the TCC valve / bore (if constantly dropping in & out of lockup.)

While it is possible to achieve 3rd gear lockup (so you could drop in / out, like in 4th), it occurs much less often. Once the TCC bore is worn, though, it really won't be able to maintain 3rd gear lockup any better than lockup in 4th.)
 

budwich

Well-Known Member
Additional questions (and I'm not a pro mechanic or trans rebuilder)
.........
As a test, you can try driving with the trans in '3', vs. D. Your gas mileage will take a hit, but you'll save additional wear on the clutches (if you're going back / forth between 4th <> 3rd), or you'll save (further) wear on the TCC valve / bore (if constantly dropping in & out of lockup.)

While it is possible to achieve 3rd gear lockup (so you could drop in / out, like in 4th), it occurs much less often. Once the TCC bore is worn, though, it really won't be able to maintain 3rd gear lockup any better than lockup in 4th.)
Not sure I understand this or maybe it is not quite what is meant. Lockup in 3rd can be readily achieved especially when pulling / towing.
 
Last edited:

Sparky

Moderator
Sounds like classic symptom of TCC lockup slippage.
Ctpowertrain transgo kit should fix that, if that's the case. Been there done that.
Only question is if you feel it is worth it on a 240k mile trans. Me, yes, but that's because I can DIY it in a day or less. But if you're not comfortable digging into your trans valve body then it becomes a bigger deal.
 

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