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GMC Safari/Chevy Astro Transmission Problem



  • bigsteve7bigsteve7 Posts: 1
    I have a 99' Chevy Astro automatic van. It has been great for me for 10 years now. It has 109,000 miles on it now and is starting to give me a problem. When I start to get on the road, sometimes it seems like it will not catch in gear or something. I can press the gas pedal as hard as I want and it will rev but will not catch into gear for up to 1/8 of a mile. It will run fine after it catches, but it is a little scary if I was to pull out in front of someone on a highway. This does not happen every time I go somewhere, very random. I think it might be the start of tranny trouble. Any advice would be greatly appreciated. Thanks, Steve
  • spike99spike99 Posts: 239

    The "factory" transmisisons in the Astro/Safaris vans are known to blow and need a rebuild. If wondering, the tranny in my previous 2003 AWD Safari with only 74,000 miles blow. Blew while driving normally and pulling away from a stop light. It needed a complete rebuild (using factory torque convertor). After rebuild, my van's tranny was better then factory. It shifted properly, it felt firm shifting across its different grears and it never slipped again. And, it handled the colder weather much better as well. As a suggestion, do "shop around" for tranny rebuild prices in your region. If you do higher then normal use, you may want to install a transmisison HD shift kit instead. And/or a better then factory torque convertor. For my needs, factory torque convertor with normal rebuild was needed. In the end, I'm glad I got my van's tranny rebuilt. Didn't like its $1,000 cost but afterwards, my van's tranny was great.

    If wondering, my tranny specialist told me to install a HD transmission cooler in my van as well. A cooler that is rated to pull a 5,000 lbs trailer. Even if only used for "soccer mom" driving conditions (which was 98% of my family's driving conditions), the factory tranny's do NOT like heat. re: Hot day, stuck in stop / slow traffic while also driving up a hill is very bad combination. A tranny Aux Cooler keeps its tranny ATF oil cooler and thus, its transmission lasts much longer. As a suggestion, do install (or simular company with 5,000 lbs rating) Aux Transmission Cooler as well. This upgrade is "well worth it" - even for normal "soccer mom" driving conditions.

    Hope this helps....

  • spike99spike99 Posts: 239
    For more details on 4L60E transmission Rebuild kit (assuming 4L60E was installed in your van's factory build) surf:

    Note: Labor to drop the transmission, install the kit, re-install the transmission and add new fluids is the costly part. The Rebuild kit (without Torque Convertor upgrade) parts isn't every expensive.

    Hope this helps as well.

  • scdesignscdesign Posts: 2
    I'm looking at buying a 2001 state owned Safari Cargo today. It's in great shape with 150k. The engine and tranny look real clean, so I think they have been replaced. The car is in amazing condition. (looks like 25-50k max, no abuse)
    problem: tranny is whining, ( sound (pitch) goes up and down with gear shift) the whine seems a bit louder in lower gears (1,2), but never goes away. (maybe in 4th not sure)
    The sound is not too loud, almost "acceptable range". In other words, If a little whine with this tranny is o.k. then this one is probably within range. If ANY whine at all is sign of trouble, than trouble is here, cause it's audible, but not overwhelming at all.
    The van is 2WD, no tow hitch, trans. fluid is clean,fresh. Van shifts fine, revs SLIGHTLY going into 2nd or 3rd, but doesnt feel like slip.
    I really can't afford down time and repairs at this time. Otherwise, even with a replacement this van would be an o.k. buy.
    Thank You
  • spike99spike99 Posts: 239
    Being a 2WD van and it appears to be clean, I'd take this van to "your" certified auto mechanics and get them to "check it out". Might cost you 1-2 hours of shop time but in the end, vehicle inspection before buying is we'll worth it.

    If I bought this 2WD van, I'd immediatly install a tranni cooler (rated to tow 5,000 lbs trailer) and add can of Lucus Transmission fix. For more details, surf:
    If wondering, my local auto mechanic recommends tranny coolers in all Astro/Safari vans - even if used for "soccer parent" driving conditions.

    I'd also replace its Main RAD cooling fluid, its rear axle fluid (with HD 90 gear oil) and ensure its engine oil cooling pipes don't leak either. If leaking, replace with 3rd party pipes - which can be created at many pipe fitting / steel fabrication shops. GM wants way too much dollars for "their" replacement pipes.

    If wondering, the factory 460LE transmission in Safari/Astro vans is known to whine. My 2001 AWD Safari's van always had a whine - even after its transmisison was rebuilt. Rebuilt because it lacked a transmission cooler the day it rolled off its factory assembly line - as per my local transmission specialist. With new transmission cooler installed, its tranny fluid ran much cooler. Which equals much longer transmission life.

    If this specific van passes your auto certified mechanic's inspections, I'd buy it (assuming its selling price was good as well). I've always had great luck with 2wd Safari/Astro vans. And being 2WD, its wear/tear replacement parts are less expensive as well. AWD replacement parts (like ABS sensors, steering - idler arms, suspension, etc. etc.) seem to cost twice as much.

  • scdesignscdesign Posts: 2
    Thank You! great to hear back on that! The deal was sealed late sat. eve. I didn't want to wait and lose a chance on this vehicle so I gambled on it. It's inagural 40 mile drive revealed no rough 1st to 2nd shift problem after hwy I've been reading about. "Whew!" "Hey wait... what's that loud whine I'm hearing ?" (at stop now). Yup, the fuel pump is buzzing like a ciccaeda. Seems thatthis is part of the expected routine, so I'm going to cut a nice access panel in the floor tommorow. I'm assuming it must be replaced as it wasnt' making the sound a day before. The engine runs very strong and starts on first crank immediately, so I'm almost wondering if the pump is o.k. and just (very) loud. This has nothing to do with the tranny noise discussed earlier.
    I saw a posting somewhere that another pump brand supplies AC Delco and can be bought cheaper but can't find it now. The AC sticker was covering over the (cheaper) manufacturers sticker!
    As for the tranny, it seems tight, however at fast take off, there is a small bit of a growl or low rumble, and it seems to be struggling a (tiny) bit perhaps( only maybe here). Not sure if it's the diff or transmission. Mostly it's the sound that catches my attention. A kind of a low rumbly take off, but with plenty of power and all that. There is a very slight rev when going into 3rd under load (foot down).Have the other vehicles out there had similar performance? The engine is very strong and starts.
  • alberta4alberta4 Posts: 4
    I have a 97 Safari with 190,000 KM on it and for the past 2 years it has problems shifting from 1st to seccond. I have read the other posts but this does not happen when the van is over heated. It first occurred last spring and I took it to a garage and they couldn't see anything wrong with it. They changed the oil and I had no problems until this spring. It started to go away as the summer has heated up and it is not a problem on the highway. It seems to "act up" after driving in the rain or launching my boat. This is why I think it may be moisture related. May be the melt after winter or exposing the van to rain or the lake is introducing moisture into the transmission? I would appreciate any help you can provide.
  • recently replaced the torque converter clutch when it threw that code, and still getting a code for an O2 sensor my mechanic who replaced the TCC checked and said its fine.
    he replaced tranny fluids n filter n said transmission looks fine.
    so here's the problem- starts up fine, no fluid leaks, no fluids burning. after driving distance, 45 min + on freeway without problems, and then coming to a stop (say an off ramp), when I accelerate I get this hard buck or jerk from the rear. if i stop again soon afterwards and accelerate (stop lights), same thing. if i drop it to D2 AT the stop and pull off, then shift up to D3 then D, its fine. or if I pull over, kill the engine, wait a minute or two and get back on the road, it stops.

    this is driving me nuts.
    mech says there's nothing wrong with my transmission that he can tell, and having him drive it for awhile didn't produce the problem. he probably didn't go far enough or stay at 65-70 mph for any length of time

    around town there is no problem. there's no coolant in the oil or vice versa or any other indication fluids are mixed. regular oil changes. all gauges read normal.

    I was told it may be a PCV valve, something about a vapor build up or blockage. ideas, insights? thanks in advance!!!!
  • All- I have a 2003 Astro Conversion Van that has given me great service. I had to rescue the wife from the local Walley Word parking lot where she could not get the van to move in revese, but slightly and then it felt like it was binding.
    I got it home replaced the fluid, filter, and substituted a quart for some lucas Transmission fix thinking that something might be sticking. I still have no reverse unless you REALLY force it, now the van will drive in neutral, but slip. I still get normal shift and can run highway speeds in drive and while doing this I tried to engage/disengage the overdrive/tow button on the shifter, but got no noticeable change in RPM.

    Thanks to all for you time to read and relpy!
  • Sounds like your radiator is leaking water into the trans cooler side of radiator.
    I can't be sure because I haven't seen your radiator.Just an ideal to look at!
  • Does your transmission come in any other chevy model?
    If so,which one?
  • I just need to know if the all astro's have the 4L60E automatic trans?
    my astro has no reverse and when it up shifts to high gear,it slips until I
    let up on the gas petal, then it goes in to high gear, and works great!
    Anyone have any advice?
    I want to pull the trans and install rebuild kit,including new bands!
  • my 96 astro has a hard shift from 1st to 2nd. i was wondering if lucas or anything like that might help. i can't afford a new trans and i need this van to last a year.
  • You could have a problem in the Valve Body,(1-2 shift valve stuck,or a damaged spacer plate , also 1-2 accumulator valve stuck)(could be 2-4 servo , most likely the pin )If it is one of these problems, trans does not need to be pulled !)
    2-4 band could be burned out, oil pump could be the problem, this will require the trans to be pulled ! You can try , some sort of sealer, hope it works, install new trans fluid and then install trans sealer !
    Astro is a good van I have an 01 and I to will need to do some trans work, but I am keeping my astro, these vans are dependable, mine has 240,000 and still starts everytime !
  • thanks for the tips. i need to take it in though, when i left for work i just jumped in and took off with it cold and when it went from 2nd to 3rd it just reved up till i let off it then it caught. doesn't look too good. i feel prettty stupid though, i just bought the van, only put 400 miles on and this happens.
  • code reader says i need a new mass airflow sensor, is it worth the $100 it costs. also if i had knocked the air intake duct loose behind it could that set the code off.
  • If your auto runs bad, you will need a mass air flow sensor, sometimes you can remove them and clean them with a can of brake cleaner, you can try this and see if it works first,$100.00 is a good price for the sensor ! But still , look on and see what they want for one !
  • my 04 astro [non-permissible content removed] up to 3rd gear and 60 percent of time will shift into drive not slam or anything pretty smooth. the rest of time it just reves and wont go into drive like its stuck or clogged. i replaced the filter and fluid and my friend suggested the brake switch which i did to no avail. does anyone have any ideas.
  • that the PCM is attempting to operate the shift solenoids. If the TPS is failing, the VSS is failing, or other inputs are missing, the transmission may operate irregularly. Just something to Check !Good Luck.
  • Had the transmission in our Chevy Astro rebuilt a month ago and it drove great! Two weeks later we go to start it and the lights on dash where trans indicator not viewable and the trans feels like it is in second gear upon throttle instead of first gear. Take it back to the trans repair specialist and they had it two days. Trouble code stored and read by their comp is a 'PO760 Shift Solenoid C'. Called us to pick it up and they said it was working temp and we needed to replace the ignition and they were 75% sure it was that, but could not say positive though. We had NO prob with ignition before. It is tight and key goes in smoothly. No electrical or dash light problemss or any difficulties with ignition or starting van. They say it is causing TRANS fuse to blow. Aprehenious, we say we will wait for $250 repair to replace ignition switch and do some checking. Two weeks go by and no problem but then fuse blows again and the trans acts like it is in second again. Wiring harness in trans was replaced when rebuilt(according to trans repair specialist). Ran our own SCAN tool and came up with PO 740, PO753, PO 758, P1860 stored codes today. We think it is indeed a bad wire to trans or a bad wiring harness and the problem is not in the column or not directly related to the ingnition. We have the GMC pro service manuals and the wiring diagram doesn't show the TRANS fuse connected to the ignition but straight back to the trans harness. Please give this very capable DIYer confirmation or retraction to which direction should be taken. Are we right or is the trans place right? If we are right we would like the trans place to put in new wiring harness or to do thourough inspection of the trans wiring rto find the short.
  • Did you determine what was the problem?
  • How do you know for sure if it is failing? Would a code be stored for it?
  • iceguyiceguy Posts: 2
    i have recently changed my trans. and just drove it 300 miles 2 day ago everything went smooth then today drove home it seemed ok but when i popped my hood i had tranni fluid all over place took it to car wash came home and cant get it to leak it still has plenty of fluid in it but wont leak any ideas
  • 1998lincoln1998lincoln Posts: 108
    Two things to would check, did you over fill the trans, if not, check the lines to raditor, might be stopped up !
  • iceguyiceguy Posts: 2
    lines to the radiator are to hot to touch, could this be a result of a plugged line , if so how would you go about unplugging the line
  • spike99spike99 Posts: 239
    edited March 2010
    My local transmission specialst tells me that ALL GM van transmissions run hot. Especially within the Safari/Astro design - that doesn't reflect the wind very well (compared to today's smaller mini-vans). He recommends ATF aux cooler (LPD Design) be installed in all Safari / Astro vans - even non-towing vans. For example, Hayden 678 or 679 LPD design.


    If wondering, I installed Hayden 679 in my prev AWD Safari van and installed Hayden 678 in my wife's smaller size GM mini-VAN. re: ooler-UpperSupport-2.jpg & ooler-LowerSupport-1.jpg

    As a suggestion, install the LPD aux cooler design (re: Tru-cool or Hayden 678 or 679) in your "running hot" GM van. These ATF coolers work great in my GM vans...

  • lind777lind777 Posts: 7

    I have a 2002 GMC Safari van. My wife went outside to try to start but it would not start. She tried a little while later and still would not start. I tried a few hours later and she said she pushes down on the gas to start so I thought that was the issue since it is electronic fuel injection.

    When I started it up the turn signals would not work and I found that fuses 1 and 16 were both blown. I researched the issue and thought it was the multi-function switch so I bought a new one off of eBay from a reputable guy who had old dealer stock. It looked brand new. I installed after a very difficult process and when I pressed on the brake pedal it blew the fuse again. Putting the turn signals on also blows the other #16 fuse after blinking on and off for 3-4 iterations.

    I removed all the dual filament bulbs and the top brake light and pressed on the brake pedal and that also caused the #1 fuse to blow.

    I removed the brake signal switch and opened it up gently and made sure the front two contacts would be coming open prior to the last contact touching. Everything looked good in there.

    The van does have a connection for trailer lights and brake controller. I reviewed those and they are all clean.

    I removed the top brake light and everything looks clean there too. The resistors all look good.

    I opened the sliding door just in case something was shorted in in there as well but that had no effect.

    Any suggestions on how to test the actual connector sockets into which the bulbs reside?

    I really thought it would be the multi-function switch but that was not it. Please ask anyone you know who may be able to help on this one as have a $4,000 boat anchor right now.

  • The transmission went out in my 96 Astro Van (reverse and 2nd gear). It had about 260,000 miles on it. I picked up one at a junkyard today (from the same year van) but had a quick question. The guys I had to deal with were a real PAIN, and were pulling all kinds of CRUD since I'm a woman. They said I'd have to have the transmission reprogrammed/reset, and if I didn't it wouldn't work right. Now, I've messed with several transmissions, but all older 67 & 70 Mustangs and a 68 Cougar---never any of this "new stuff"...... Were they telling the truth, or just trying to pull one of my already long legs?? Would someone please let me know. I can't seem to find anything about it online, but just wanted to double check.
  • pcvanpcvan Posts: 2
    just pulling your leg; swap it and go
  • Did you ever find out what was wrong? I have a 2000 astro and your story reads almost exactly to what mine is doing right now. I have replaced the computer, throttle position sensor, speed sensor, engine coolant temp sensor, and even put new ends on all the grounds. I had my tranny rebuilt about 7 months ago and the shop tested the transmission as well, but the tranny keeps going into safe mode, which only lets it run in second and third gear. I have run out of ideas of what else to do to try and fix it. Please let me know how your van turned so i can at least know what direction to try next. Thank you.
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