Mechanic said I need a new transmission?

I own a 1998 Pontiac Tran Sport with 152,000 miles (mostly city) and it rarely needs to see a mechanic except for oil changes and routine maintenance. The minivan has trouble accelerating from 0-20mph lately but accelerates just fine after it hits 20-30mph. The van also hesitates and stumbles if I am driving more than 60mph for long periods of time but will drive normally when I slow down to 55mph.

I took it to Aamco because they diagnose check engine lights for free and they tell me that one of the solenoids in the transmission is faulty which is causing it to shift from 1st to 3rd gear when I am accelerating. They said it costs $400 but it would be a waste to repair it because a transmission with that many miles needs to be rebuilt or replaced which is really expensive. They said the solenoid would just break down again because of the transmission’s mileage and age. Does anyone know if replacing the solenoid is a waste of money? Or are they just trying to get me to purchase an unnecessary repair?

2 questions: 1) Have you kept the transmission serviced, as well as the motor? Regular fluid changes and at least a couple filter changes?

And 2) Have you talked to a real transmission shop? Or have you only talked to AAMCO?

If you haven’t kept it maintained, then they’re most likely right, and there’s a lot of damage inside. If you have, get to a real transmission shop. Let THEM diagnose it for you. STAY AWAY from the chain shops.

Yes I have flushed the transmission oil throughout the 10 years of ownership as directed by GM. No, I have not talked to a real transmission shop. It’s hard because I work full time and I have a very menacing boss who won’t let me have the time to take it to a mechanic.

The easiest thing for a place like AAMCO to do is just replace the transmission. There are a number of reasons for that. It’s easier, takes less time, provides you with a guaranteed unit they know they won’t have to mess with (unless they screw up the install), and they can then send your old transmission to a proper rebuilder, and have it available for the next customer. They don’t want to “fix” it, only replace it.

If you want it fixed, you’ll need to visit a transmission shop. Be warned, they can’t do it in a half day while you’re at work. You’ll need some other form of transportation while they fix it.

Next time you have CEL on (or right now, if it’s on), go to your local auto parts place, and ask them if they read codes. Then post the codes here. That actual codes, mind you (like P1234), and not what they tell you they think it means. Places like autozone, o’reillys, and the like will normally do it for free.

They SEEM to be fishing for a nice big Juicy Job to help ease their Boat payments if you ask me.

The solenoids on an automatic transmission exist solely to “shift” hydraulic fluid from one avenue (gear) to another…they are remote switching devices. Hondas are famous for having their Tranny solenoids front and center for you to be able to see and service. If your 1-2 shift solenoid or your 3-4 solenoid is not working properly SIMPLY replace the solenoid…they unbolt…usually with one bolt and one plug. Usually they are interchangeable so a lot of times we switch them around to see how the problem moves or what gears are THEN affected…

SO in a nutshell…your trans deserves one or both new solenoids…they should be rather cheap and usually easy to replace… Not sure if this is like a Honda tranny…but if it is…it is mind numbingly easy to replace one… Now if they decided to stash the solenoids INSIDE your tranny…I dont know…but that would complicate matters greatly.

But to answer the questions on your mind. I would definitely replace the affected solenoid (IF THEY ARE EXTERNAL AND EASY TO DO) If internal it might be more trouble to replace them bec they may have to disassemble the entire trans to do so…but that would seem a very stupid thing for the trans company to do…STILL doesnt mean they didnt do that. MUST FIND THIS OUT FIRST…hopefully they are external and easy to do… The solenoids are simply electromagnetic switches…when activated they move from point A…to point B… and in doing so… It changes the path of the hydraulic fluid in the tranny… SO when the pressurized fluid is going down path A…you get 1st gear…when the solenoid is activated the solenoid “switches” the path of the fluid…to give you gear number 2…so on and so forth… they are controlled by your ECU by using vehicle speed, throttle position and engine rpms to know when to make the switch.

SIMPLE devices doing a simple job…so if one is faulty just swap it out and the issue will go away…that is IF the internal clutches etc inside your tranny are still ok…and there is no reason to doubt their integrity simply because a shift solenoid wont shift from point A to B.

Go to an independent garage OR look it up on the internet…maybe you can get a picture of the shift solenoids and their location on the tranny…and maybe you can simply swap one out yourself. Like I said…on a HOnda…you could do it with your eyes closed…literally. Hope this helps…

If the issue is one of the ACTUAL solenoids then definitely do it…if the solenoids ARE WORKING then this points to an internal tranny issue…with the clutches or something else… TRANSMAN on this site can elaborate. SO you need to find out if they said that a solenoid isnt working and on the surface is the only external issue they see…YOu cannot get into said gear if the solenoid doesnt make the switch for you…they are easily tested also…they are just electromagnetic switches…you hook them up t0 12V and listen for the electromagnet to move or shift from point A to point B…

Too much info? Does this help you? Hope so… Blackbird

The problem with the solenoids in this transmission is that they are not easy to replace. They have to be accessed through the side cover of the transmission and there is no way to access it without at least dropping half of the subframe or removing the transmission entirely.

As such, I’m not sure the same advice wouldn’t come from any transmission shop. At 152K odds are good that “something” will happen next and then the thing quickly becomes a money pit. This is no reason not to go to a “real” transmission shop.

You say that the trans was “flushed” according to GM schedule. Well, that’s bad for a couple of reasons. One is that it indicates that your original filter might still be in there. That’s bad. The other is that manufacturer recommendations are not designed for maximum transmission life. Many transmission techs say that an automatic should get a new filter/fresh fluid every 30K miles. That’s not what GM says.

Anyway, personally I would be unlikely to spend any money to “save” this van. Its a situation where I would be tempted to drop a cleaning-type additive (e.g. Seafoam “transtune”) into it, drive it for a while, and then drop the pan to inspect and change the filter. Note that this is NOT fixing the transmission - just a cheap, simple way to see if you could get more miles from it. Cleaning type additives have a chance of cleaning up/freeing problematic solenoids. But if you want to keep this van on the road, take it to an independently owned, local transmission shop for proper inspection & repair.

Often, Trans-Medic, Trans-X, Sea-Foam trans-tune, etc., will correct sticking transmission valves and $5 to $10 is a cheap and harmless effort to get your money’s worth out of the vehicle. If adding a treatment improves the situation I would suggest servicing the transmission and adding another dose of the product. But that “menacing boss” sounds like a worse problem than the transmission. Life’s too short. I hope you find a more promising posting soon.

AAMCO = All Automatics Must Come Out!

First off, I wouldn’t let AAMCO touch anything on my car. Find an ATRA member shop.

The solenoids are electric so tonics won’t have any affect on them. I had the solenoids changed in my Olds many moons ago and no problems. It was about $400 but the symptom was limp mode in 2nd gear. So I think you at least need another diagnosis.

Its a crap shoot whether or not to go ahead and overhaul or not. I had my Buick overhauled at about 350K just because I traveled all over the state and just wanted to make sure it was good. The ATRA shop said it really wasn’t that bad when they tore it apart and still had a lot of life left in it. If its 150K of city driving though, that might be different. I’m still not convinced its not the engine though with your description.

The solenoids are electrically activated little motors. They have moving parts - tiny ones. Tonics can help if its a sticky parts problem. Obviously not if they are electrically fried.