Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Transmission - Rearend (http://www.hotrodders.com/forum/transmission-rearend/)
-   -   4L60E Shift Problems (http://www.hotrodders.com/forum/4l60e-shift-problems-77841.html)

chianesi 01-04-2006 07:52 AM

4L60E Shift Problems
 
I have a 95 blazer 4.3L Vortec with the 4L60E 4WD. The tranny wont shift out of first at all. Could it be something as simple as the solenoids or much worse?

Crosley 01-05-2006 10:03 PM

Quote:

Originally Posted by chianesi
I have a 95 blazer 4.3L Vortec with the 4L60E 4WD. The tranny wont shift out of first at all. Could it be something as simple as the solenoids or much worse?


could be many things...... by chance is the speed-O functioning correctly?

If the tranny is in first gear , that tells me the tranny is receiving the commands for 1st gear from the PCM

:cool:

chianesi 01-06-2006 04:14 PM

It appers that the speedometer works correctly, the tranny just wont shift out of first. I understand that the shifts are controlled by servos which are in turn controlled by the computer. Could it be that the servo that it supposed to take it from first to second be bad? I'm reaching of course, but that is the only thing that makes sense to me at this point. One more thing, if I were to manually shift through the gears by taking it from 1 to 2 to D, and it work, could that confirm that the servo(s) be bad as well??

I hate computer controlled stuff :smash:

Crosley 01-06-2006 07:40 PM

Quote:

Originally Posted by chianesi
It appers that the speedometer works correctly, the tranny just wont shift out of first. I understand that the shifts are controlled by servos which are in turn controlled by the computer. Could it be that the servo that it supposed to take it from first to second be bad? I'm reaching of course, but that is the only thing that makes sense to me at this point. One more thing, if I were to manually shift through the gears by taking it from 1 to 2 to D, and it work, could that confirm that the servo(s) be bad as well??

I hate computer controlled stuff :smash:

nope on the solenoids.....


both solenoids need to be 'on' for first gear. That is why I made the comment about the PCM telling the tranny to be in first gear. Unless there is something else happening that you are not aware of.

If both solenoids are clogged up , then the tranny would stay in first gear. If the solenoids are clogged up , then something is wrong internally with the tranny.

This vehicle still backs up fine ?? RE: reverse works?


:cool:

chianesi 01-08-2006 10:54 AM

Update
 
Yes the tranny shifts into reverse just fine, pretty smooth actually. In further testing, the tranny WILL shift into second but NOT into third. If I were to guess at the dipstick marks, I think the tranny has about 1 qt. too much fluid. One more thing, when I was checking the engine over I noticed that the radiator in the blazer must have come from one with a manual tranny cause the two cooler lines that are supposed to connect to the radiator are connected to each other with a piece of rubber hose, so much for cooling the tranny :spank:

Crosley 01-08-2006 11:10 AM

Quote:

Originally Posted by chianesi
Yes the tranny shifts into reverse just fine, pretty smooth actually. In further testing, the tranny WILL shift into second but NOT into third. If I were to guess at the dipstick marks, I think the tranny has about 1 qt. too much fluid. One more thing, when I was checking the engine over I noticed that the radiator in the blazer must have come from one with a manual tranny cause the two cooler lines that are supposed to connect to the radiator are connected to each other with a piece of rubber hose, so much for cooling the tranny :spank:


IF 1st and 2nd gears are operating , NO 3rd or 4th gears would indicate the 3-4 clutch pack is the problem.

The 3-4 clutch pack in this tranny has been a weak point since the tranny was introduced in the 1980's.

You have not indicated a mileage figure on the vehicle?

:cool:

chianesi 01-08-2006 11:40 AM

Your right...sorry. The blazer has 165,000 miles

mike 96 ws6 01-08-2006 07:54 PM

Quote:

Originally Posted by chianesi
if I were to manually shift through the gears by taking it from 1 to 2 to D, and it work, could that confirm that the servo(s) be bad as well?? I hate computer controlled stuff :smash:

I am posting in this thread for more of an educational quest for my own knowledge rather than attempting to solve your problem. I am very confident Crosley can handle that part, provided you supply him with accurate information. But I would like to chime in if that's okay with you guys?
chianesi, did shifting manually allow it to shift to 2nd, which, as indicated by your next post, is now accomplishing that shift?
Quote:

In further testing, the tranny WILL shift into second but NOT into third. If I were to guess at the dipstick marks, I think the tranny has about 1 qt. too much fluid. One more thing, when I was checking the engine over I noticed that the radiator in the blazer must have come from one with a manual tranny cause the two cooler lines that are supposed to connect to the radiator are connected to each other with a piece of rubber hose, so much for cooling the tranny
#1 overfilled fluid level can cause a foaming effect of the fluid in the reservoir {pan} since, at that level, the fluid can contact geartrain parts in motion, which serve as a 'blender' {for lack of a better term} like the one in the kitchen. This foaming, which is physically a fluid / air mix, can cause pump cavitation and starvation which produces lack of pressure output as well as inconsistant output volume. Long story short: This is very 'not good' when the factor of an automatic transmission relying on constant fluid flow at the right pressure is a major {if not the most important} requirement for proper operation and a normal life span.
Also, the cooling lines being routed in a cooler bypass fashion is obviously a mistake since heat is a major cause of auto tranny failure. I won't go into detail since none is needed. It is a mistake. But it is good you provided that information since this could be a substantial factor as to the cause of your problems.
And concerning your statment of "I hate computer controlled stuff".
I understand perfectly what you mean. I was of that same opinion for a long time. But nowdays, after learning what little I know about car computer systems, and spending the $ for some expensive, but very useful, tools which are very neccesary for diagnostics, repair and modification of the powertrain controls and related systems on these vehicles, I have come to appreciate the advantages that they can provide over the older systems that I grew up with. I have just enough knowledge and equipment to be able to be fairly competent at dealing with computer controls on cars and although I am constantly being asked for help by other mechanics with computer problems they are unable to solve, and edit PCM program parameters in my car, as well as several others, with excellent results {so far}, I realize I know very little about the vast opportunities that these new systems can provide. I did not like running a SBC / BBC without a 4-barrel or two because I built a few that I was proud of the performance results, but after I got past that mental wall against the unfamiliar / in-experienced, for me, computer controls, I now see the advantages and I have much more fun with the scope of control I can have making performance improvements available through punching laptop keys, rather than having to deal with those darn scored Q-jet main jet needle actuator piston bores. :D
This way I can spend that carb headache time building a forged bottom-end to handle the power gained by the next programming ideas I want to try.
And like that is not enough typing to bore everybody, is the Blazer transmission with 165,000 miles the original unit with no internal service so far?
And one more thing:
Quote:

If I were to guess at the dipstick marks
.
Is there a reason a guess is needed rather than a standard observation of the level indicated on the dipstick after the powertrain is at operating temperature. Just curious about that.
Sorry about the length here. Just trying to help :)

chianesi 01-08-2006 09:45 PM

Shifting the tranny manually had no affect on the overall problem, it shifted into 2nd on its own, it was so smooth I didnt notice it the first time. The previous owner stated that it had a recent fluid change and mentioned no overhaul or other mechanical problems with the transmission, he only stated that.."sometimes it shifts and sometimes it dosent".

Mentioning the dipstick. I made that remark because at looking at the hash marks on the dipstick and looking at where the fluid actually read, I would guess that it was a Qt. to full.

I took the blazer out for another test run and I paid closer attention to the shift into second, it shifted smooth but still didnt shift into third. I slowed back down allowing it to downshift back into first and this time instead of creeping into a shift a gave it the gas and at the point where it should have shifted into third it almost felt as if it fell into neutral and the RPM's shot up to around 5k.

Hopefully this info helps...

sbchevfreak 01-09-2006 02:50 PM

Quote:

Originally Posted by chianesi
I took the blazer out for another test run and I paid closer attention to the shift into second, it shifted smooth but still didnt shift into third. I slowed back down allowing it to downshift back into first and this time instead of creeping into a shift a gave it the gas and at the point where it should have shifted into third it almost felt as if it fell into neutral and the RPM's shot up to around 5k.

Quote:

Originally Posted by Crosley
IF 1st and 2nd gears are operating , NO 3rd or 4th gears would indicate the 3-4 clutch pack is the problem.

The 3-4 clutch pack in this tranny has been a weak point since the tranny was introduced in the 1980's.

You have not indicated a mileage figure on the vehicle?

:cool:


I think your answer has been found already. :thumbup:

Crosley 01-09-2006 07:35 PM

Quote:

I took the blazer out for another test run and I paid closer attention to the shift into second, it shifted smooth but still didnt shift into third. I slowed back down allowing it to downshift back into first and this time instead of creeping into a shift a gave it the gas and at the point where it should have shifted into third it almost felt as if it fell into neutral and the RPM's shot up to around 5k.

Hopefully this info helps...

chianesi,

just an FYI if needed.

i've built automatic trannys for decades. I stilll build them for a living. I build several 700 / 4L60 trannys per week.

I believe your problem is the 3-4 clutch pack. Sounds like your tranny needs a proper rebuild.

:thumbup:

chianesi 01-10-2006 04:16 PM

Thanks for the input Crosley..I just wanted to be certain. Thanks again!


All times are GMT -6. The time now is 07:45 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.