nateK

I apologize in advance for the potentially unnecessarily lengthy post...

Any help greatly appreciated… My 1993 GMC Vandura G2500 with 4.3L and 4L60E transmission was purchased 4 years ago from the original owner with 113k on the OD. The PO was meticulous with maintenance and kept a hand written log of his oil changes (every 4k miles) and recommended GM service intervals (performed by GM at the dealership he purchased from). Before anyone starts in on the 3/4 ton ‘G2500’ and the fact that the van is a SWB with a 4.3, the PO special ordered the van to his specs including the ‘semi-conversion’ package, the 4.3L V6 and half ton axle within the 3/4 tow package (according to records kept/sales receipt). The van now has 169K (when the OD stopped working, I’ll explain more) on the OD… the time/line issues are as follows…

-When I purchased the van it had an odd issue with the shift from 1st to 2nd when cold. I’ve seen this referred to as ‘looming’ or ‘hanging’ shift. The van when placed in drive after a cold start would act as if the tranny had a moderate stall (shifting as if it was a 3k or 3500 stall or so). It would only do this on it’s very first shift from 1st to 2nd and only when cold. After it would shift to 2nd it would shift up and down smoothly for the rest of the day.

-I had zero issues with the van aside from maintenance that was due; front and rear brake job, new tires, new battery, oil change, oil filter etc. The van never had the check engine light on, no trouble lights whatsoever and passed it’s first inspection with flying colors including the strict emissions requirements Texas has for vehicles less than 25 years old. (side note; the heater core has been out since purchase so the heat does not work. Being that I live in Texas I never bothered to address this… the AC once charged blew/blows ice cold. The AC compressor motor had a failing bearing and would scream high pitched note, so that was replaced with a new unit).

-The first issue I encountered was the parking brake indicator light and the ABS light came on one morning after the engine was fired up and did not turn off as usual. I went through the basic trouble shooting; checked the masters for suggested brake fluid levels, check the E-Brake was disengaging, checked the sensors at the wheel and under the masters etc). After finding no obvious issues I consulted my shop manual and ran through the on/off sequence to reset the warning lights… the code that would return showed ‘reset test fail’ which I read through forums and determined that the ABS control module had potentially failed. This issue occurred after about 25k miles and 10 months to a year of owning the vehicle and driving daily.

-The firs major issue occurred after having driven from Austin to Houston to pickup a motorcycle. I was pulling my very light 8’ single axle trailer on the way there (empty) with no issue and then the same trailer with a 450lb motorcycle on the way back… The drive is about 170 miles. Once I loaded up the bike and got back on the road, everything was seemingly normal… no warning lights, no odd shifts… nothing odd. I sat in traffic for about 15 mins at a near stop at the west edge of Houston… finally got back on the freeway and was streaming down the freeway at 65-70mph with no issues. I realized I should get gas after about 40 mins of strait driving on the freeway and exited. Once exited I came to a stop at the stop sign near the gas station and realized my speedometer was not working, my odometer was not working… and then when I took off from the stop sign into the gas station the van was seemingly ‘stuck’ in 1st gear. I pulled around, got gas and called a buddy for some advice. Keep in mind I was an hour and a half from home in the middle of nowhere. So, I let the van cool off for 20 mins, fired it up and started on my way… van would not shift from first. Reverse worked, it would not ‘hard shift’ nor ‘jerk’ when shifting into gear and never once slipped. I decided to manually shift down to 1st, take off, pop into 2nd (it went no issues) and then pop into drive (non-OD drive)… it went to 3rd. After driving in 3rd (still no OD, trip meter or speedo) for around 20 mins, I popped it into OD-Drive thinking it may shift to 4th/OD and the van acted as if it was popped into neutral. In the motorcycle world this is known as ‘false neutral’. I limped it home on access roads at what sounded/felt like a low RPM as I didn’t want to put unnecessary stress on the motor.

-After getting it home I had a buddy come take a look (GM hot rod mechanic). The transmission fluid was not brown/burnt/didn’t smell. Again, the tranny never once slipped and the ‘check engine’ light never came on. I let the van sit while I did some research… which lead me to believe that the 1 to 2 and 3 to 4 shift solenoids could have failed. I order two BW lifetime solenoids, a new gasket and filter and new fluid. While waiting for those products to arrive I decided to take the van to another friends shop about 10 miles from my house (keep in mind I hadn’t driven the van for about a week now and it had been sitting since it returned from Houston). The van fired up… AND DROVE LIKE NORMAL as far as shifting through the gears was concerned… however, the van drove like its was half power… as if it was driving up hill pulling a motorhome. Confused I tried to explain it to the buddy at the transmission shop… he insisted that if the tranny never slipped that the solenoids and new fluid was a logical step.

-Replaced the shift solenoids, gasket and fluids as planned… the ‘looming shift’ from 1st to 2nd was seemingly elevated.. however, the van still drove as if it was half power from where it had been since I owned it. At the time the van was my only vehicle aside from my wife’s new car, so I did not attempt to recreate the issue (by driving for a length at highway speeds) as I needed the van to get to/from work if raining or hauling when I could not take my motorcycles.

-I drove the van like a granddad for around 4 months… though it was seemingly gutless, it would shift through the gears fine and functioned for me around town. I had a good friend strike up a conversation about it at a bar and decided he wanted to check it out the next day. He came over and we went for a ride… he immediately noted that the motor sounded like a jet engine and that he thought the fan clutch was shot and putting extra stress on the motor. I popped off the serpentine belt and took it around the block… low and behold it seemed at least as powerful as it had been before… hard to tell as it had been so long since it drove right, but it was notably better than with serpentine belt on. Local parts store had new fan clutch in stock, came back and installed, put belt back on… seemed to be better. I took it to a concert with the wife about a week later which required a 20 mile drive on the freeway… ran great, had enough power even with AC on and didn’t have issues shifting after coming to stop. Drove like that for around 2 months (in that time I didn’t drive daily, rarely took not the freeway as the weather was nice and I was riding my bikes often.)

-Fast forward a few months of sparingly driving the van… hopped in one day, started up, pulled out and low and behold… looming shift between 1st and 2nd when cold… gutless from 2 to 3 and 3 to OD… right back where it was. Took on freeway, ran fine for 15 miles, pulled off freeway, down shifted fine, took off from light and van stuck in 1st. This time, check engine light came on… limped to my destination, came out after 20 mins, van started, check engine light lit up… manually shifted from 1st to 2nd, 2nd to 3rd… cruised for 5 mins… check engine light turned off… OD would not engage when in main DRIVE… limped home at 40mph in 3rd. It now will function as it has since the first issue (shifting fine but as if it was pulling a heavy trailer) UNLESS driven above 45 MPH... once it shifts into OD and then back to 3rd it will not find OD at all... operates as if it was not in OD Drive.

The van now drives like it has half power. It shifts like it has a stall and when driven for any notable length and then stopped at exit/light/sign it will not shift from 1st unless manually. The two times the check engine light came on it turned off before I was able to scan to see what code it was throwing. I really don’t want to spend the money on a rebuilt tranny and the weekend to put it in if that will not elevate the problem… If anyone has ANY THOUGHTS I would appreciate it… Last note, the parking brake indicator light and the “ABS” light have NEVER turned off and have always remained on… my ABS does not work and hasn’t since that light turned on. The CAT makes sounds as if it’s clogged (noticed this last week) so I plan to bypass… If there’s something I can do, I’ll try it. If it boils down to rebuilding the tranny I plan to bite the bullet and put a 350 and 4l60E in… but I didn’t want to do that until late next year. Thanks in advance for any thoughts.

Christia Hall

This sounds a lot like my van which I recently purchased for a really good deal knowing that this problem existed.

It purrs on the highway. Seems to try to jump gears or hesitate to accelerate/drives at half power or stalls at 5 mph, all when cold. Also the heater doesn't work and it smells gassy. That part I think has to do with probably needing a new O2 sensor. I just want to make sure this thing doesn't blew up on me going to work or weekending.

Mine is a 1993 GMC Vantura 2500.