ok i'll start off when the i first noticed the problem..

earlier this summer i was driving across the highway for about an hour.. and when i turned off the off ramp i noticed a whining sound that got faster/louder when speeding up and quieter/slower when slowing down... i stopped the truck and tried the 4WD and after going into 4WD i applied the gas and it sounded like it slipped out as there was a couple of quick clunks and the back wheels only spun..

i drove the truck to the nearest camping spot with the whining still in it happening as mentioned above.. left the truck shut off for an hour or so and everything was fine.. i also had a mechanic take it for a drive and look it over and he said everything was fine..

about a month ago the same thing happened.. but i noticed when i slowed down almost to a stop there was a clunk that sounded like it came from the transfer case/transmission.. stopped the truck shut it off for half an hour and everything was fine again...

now on another note my dad has a '99 Jimmy and has the exact same problem.. except when his clunks when slowing down it stays gone.. mine doesn't.. but his happens more frequent than mine.. and mine only happens every couple of months..

now back on topic of MY (lol) truck.. same thing happened to me the other day on a quick 20 min highway drive of 110kmh.. and when i stopped the truck and got out you could smell a strong burning oudor.. everything seemed fine again an hour later.. trans fluid looks good..

and finally tonight after an 45 min drive of an average 50kmh and no highway i pulled into my dads just now and when i put the truck in reverse there was a loudish clunk when the trans engaged reverse but seemed fine otherwise.. put the truck in drive and another clunk was heard but when i give it gas it has no power and barely moves..

reverse has lots of power.. but drive has none.. trans fluid looks good.. and i'm lost...

any help would be greatly appreciated.. THX in advance to any and all that may be able to help me out with this problem.. and my dad too for that matter lol THX

EDIT: almost forgot auto trans - push button 4WD - 175,000km on it

EDIT #2: just realised dad got one of those Maxiscan tools so i just scanned for codes (i always have a small evap leak for some reason so the check engine light is always on lol and can't find it but that's minor).. and the code came up P0758 - Shift Solenoid B Electrical .. but would that have been causing the problems mentioned above???

also i found Swartlkk's post here about the problem>>> https://blazerforum.com/forum/showthread.php?t=28393 but that looks like a little more work than just replacing a part so a garage it is i guess.. unless someone has a little info that may help..

EDIT #3: ok so i cleared the code.. code comes back on within 15 seconds with the truck running in park.. took it for a test run and cleared the code while driving and the code stayed off.. truck kicked down again.. but as soon as i slowed down to almost a stop the code reappears... and no power again.. so i'm guessing it reverts back to third gear only again.. i checked the freezeframe data after shutting the truck off and clearing the code.. then restarted the truck and the check engine light came right back on... and i'm not sure if this may help someone help me diagnose my problem.. but here goes.. what it read..

DTCFRZF - P0758
FUELSYS1 - 0L
FUELSYS2 - 0L
LOAD_PCT(%) - 3.5
ETC(F) - 165
SHRTFT1(%) - 0.0
LONGFT1(%) - 2.3
SHRTFT2(%) - 0.0
LONGFT2(%) - 0.8
MAP(inHg) - 11.5
RPM(min) - 689
VSS(mph) - 0
MAF(lb/min) - 0.845
TP(%) - 0.0

i don't know if any of that will help but i figured if there was anything wrong there someone would let me know... and i also thought i'd mention that the SHRTFT/LONGFT's were all negatives during the test run.. and THX again

 

just bumping this thread to see if anyone has had any thoughts yet.. the guy who does the work on my truck says he sends this type of work to a friend of his and is waiting to hear from him..

however my cousin who is always fixing things and very mechanicly inclined says he wants to take a look at the info posted in the other thread regarding wiring ect and give it a try if i'll let him..

just wondering what people here think..


also i was wondering how much this has cost others to fix in the past??? THX


*EDIT* i have a couple of quick questions for someone who has dealt with this problem before..

the guy who does the work on my truck called me today and told me he was talking to his friend and that it's not a very big job to fix.. he said it's just the shift solenoid in the rear of the transmission, closest to the passenger side..

1. is this as simple as it sounds..

2. what else should i pick up when attempting to fix this..

THX again guys

 

I hate to point out the obvious, but have you attempted any of the diagnostic steps presented in the DTC sheet you linked to in your original post? This code does not immediately mean that the shift solenoid is bad and further diagnostic steps should be taken to determine if that is the cause of the code. This code could be caused by a malfunctioning solenoid or a damaged internal or external wiring harness.

It could be a simple as it sounds, but proper diagnosis is key to not wasting time and money. Do not get hung up if you do not have the tools called out in the DTC chart. Most of the testing can be done with a test lamp and a multimeter.

So, what else should be done while you are in there... You could go through and install a shift kit. This would require the removal of the valve body. If you decide to go that far, it wouldn't be a bad idea to go over the valve body doing the updates that are available. One key update would be the P1870 fix kit which deals with the TCC apply valve. Aside from that, you could get into replacing the servo's with either corvette models or aftermarket ones to increase shift firmness if you'd like. All of this can be readily researched on the internet as the 4L60E transmission is very common.

As far as the whining is concerned, it is possible that the front axle is not disengaging properly. It all depends on where you thought the noise was coming from. If it was coming from the front, it likely is the front axle engagement mechanism messing up somehow - a topic that has been covered in pretty good detail in other posts on the forum.

 

THX Swartlkk... problem fixed... i picked up both of the shift solenoids from the dealer for $47 each.. figured it was just as well to replace both of 'em seeing as they are right next to each other..

and also bought the transmission filter and gasket but ended up bringing that back because at the dealer it was $115 and at UAP/NAPA it was $38.. big difference

on another note i always feared transmission work and would never attempt to fix it myself.. minor problems anyway lol.. but after watching the guy who does the work on my truck do it.. i know now that it's a piece of cake.. i was actually amazed at how simple the solenoids were to replace and even more by the transmission filter..

also for others looking into doing this.. i found this video showing how easy the shift solenoids are to replace.. http://www.youtube.com/watch?v=OGckmJK2rNQ .. just a horse shoe clip and the plug..

and i was also amazed at how many how to's are on youtube for the transmission..

anyway just wanted to say THX again for this awesome site..


on a side note... as for the whining i'm almost sure it is the front axle not fully disengaging.. it happened on the way home from the garage last night again.. and while waiting for my fiancee i decided to try the 4WD HI/LO and 2WD.. everytime i pressed the button there was a squealing/screeching noise from transfer case as it was trying to engage disengage.. and after 3-4 cycles of going back and forth through them i heard 2 or 3 clunks as if it wasn't going in properly.. so that will be my knew project to fix.. but i'll save that for another thread after doing some research here..

and while having the truck on the lift i also noticed the front drivers side axle seal is leaking again after a year or so.. the mechaninc also told me both lower ball joints are gone again.. a year later.. god bless Moog and there lifetime warranty..

but best of all.. when i got home last night i noticed the fuel pump is starting to whine.. LOL.. i think my truck hates me LMAO

anyway THX again