New to the forum, and have read several similar, yet not the same problems. Thanks in advance for your help!

'97 Blazer 4WD with 4.3L with 167,000 miles. Tranny rebuilt at 80,000 by national chain shop.

Current issue is Tranny won't shift into OD (is this the same as 4th?) so on highway driving at 65-75 MPH the RPM's are 3000 plus. Not sure, but may not be shifting into 1st either, or may be doing so only when cold. When starting out from a dead stop it is really sluggish - the engine must rev way up to get it to move. I'd compare this to trying to start out in a manual transmission in 2nd or 3rd gear. After reading other posts on this topic I began to wonder if it is not starting in 1st, and that this is related to the OD problem. The Check Engine light is on, and the Auto Zone guys read the code - trying to remember exactly, but it said something about tranny not shifting when computer tells it to - may have been shift solenoid malfunction. Checked fluid - it was about 2 1/2 quarts low so I added until correct (checked hot with tranny in park.)

I don't do the work myself unless its simple and quick, but I need some advice - don't have funds right now for major work. I'm hoping for cheap quick easy repair - or at least something to get me by for awhile.

Other recent troubles may be related too - so I'll mention here for reference. This spring we found tranny fluid in the ashtray and dripping down inside the dash - same time climate control stopped working. Dealer said that a part had malfunctioned (again - this happened two years ago too) which allowed the dash vacuum to suck tranny fluid into the climate control system. Expensive to have them clean it all out! Wondering if this is related, and if the dealer is giving us the straight story. I am not positive, but I don't think the check engine light was on before we dropped the truck off at the dealer to have this repair done. Could the dealer have caused the tranny problem? Any thoughts?

Many thanks in advance for your help!

BTW - what is with the apostrophe problems here? I swear I only put in one in each place!

 

About your transmission problem, we really need the code. From the sounds of it, the transmission is in the "Limp-In" mode which locks out torque converter lockup and puts the transmission into 3rd gear and reverse only with manual 2nd gear starts by pulling the shift lever down until the 2 is illuminated.

About your problem prior with transmission fluid in the vacuum system, that is a combination of failures. The first failure was the input seal on the front of the transfer case allowing transmission fluid to fill the transfer case. The second failure was the vacuum switch on the top of the transfer case allowing fluid to enter the vacuum system. No way to tell if that problem still exists, but it likely is not causing the issues you are experiencing.

With the code, we can help diagnose further.

About the apostrophes... The forum software is having some problems so just ignore them (or do not use them all together).

 

I'll ask Auto Zone to re-pull the codes, and then post them here. It may be a week or two before I can get there though. Thanks for your input so far.

 

The problem is a simple one, your t-case input seal is leaking. What it means is your tranny fluid is leaking into your t-case. Once your t-case gets full the fluid has to go somewhere, and it gets sucked up into the vacuum lines. The vacuum lines run up the back of your engine into a tee. One side of the tee goes to the engine to provide vacuum. The other leg on the tee goes into your dash and provides vacuum to change your HVAC setttings. So yes, this is related.


The simple quick hope to God it works solution to get me by for?
Pull the top plug out of the back side of the t-case and let it drain to proper level. Till it stops draining is proper level.
Disconnect your battery for a few minutes, hopefully that will reset the tranny.
Add a quart of Lucas Tranny fix. Worst case is some will spill out the vent hose on the tranny. You already know it leaks into the t-case.

You already know what it costs to get the HVAC system fixed.
If your tranny doesn't start working your looking at replacing that too.

 

Short update - while I haven't gotten the codes pulled yet, I have done some additional testing based on your posts. Here is what I've found:

1. When vehicle has been sitting for several hours or in morning(cool transmission) the tranny distinctly shifts from 1st to 2nd to 3rd - reverse also works fine. Have not had the chance to check overdrive at cool operating temperature.
2. Once system warms up it is as you described where 1st and 2nd do not work (in addition to overdrive) but 3rd and reverse do work. I can manually shift into 2nd in this condition, but it won't do it automatically.

Your description of the fluid leaking into t-case sounds like what the mechanics described. So if I understand right - you are saying that until such time as I get the seal replaced (presume this means whole tranny comes out?) I need to check the t-case on a semi-regular basis and drain excess fluid from it?

Also curious about using the Lucas - this is the thick goopy stuff if I recall correctly. Since I have topped off the tranny with regular fluid I assume that I cannot add the Lucas until the level has dropped again?

Thanks for your help! I will get the codes in about a week and post them.

 

Okay, here is the update. Had the code pulled - P0785 - Transmission 3-2 shift solenoid.

An update on the drivability: It really seems to be temperature related, as yesterday I was able to drive for about 90 minutes early in the morning (below 45 degrees) and all gears worked fine, including overdrive. However, when it gets warm it goes into the 'limp-in' mode you talked about where only R, and 3rd work, but I can manually shift into 2nd.

Questions:

1. What am I looking at for repairs - I assume the code means a solenoid has to be replaced - is this pricey?
2. What about the seal which goes between tranny and transfer case - is this a pricey repair - does it require removal of tranny?
3. Would adding the sticky LUCAS get me by for awhile longer? How do I remove some fluid so I don't overfill with the lucas?

Thanks again for your help on this! With the cost of a new vehicle I am thinking a tranny replacement may just be the way to go here, even with 169,000 miles. We sure have loved this Blazer!

Thanks.

 

[align=left]To replace the t-case input seal, you only need to remove the transfer case. It can be quite heavy, but is not too involved as far as removal goes.

When I get some time later, I will look up that transmission code and post.
[/align][align=center] [/align]

 

Here ya go, i just replaced my 3-2 sensor https://blazerforum.com/m_178697/mpa.../tm.htm#178697. Its easy to do and only buy from the dealership. Its only $36.