Complaint Review: Cottman Transmissions - Flint Michigan

The weight of the converter is called mass. Rotating mass gets heavier the faster it spins. This is why wheel/tire assembles get balanced, as do flywheels, flexplates, and torque converters. It has nothing to do with the clutch locking or unlocking. It spins as long as the engine is running. The faster it spins, the more out-of-balance it will become, not just at "2000rpm" and "under load, accelerating". I will not attempt to teach you Physics 101 here. The slippage is a seperate issue from the vibration. I have readily stated the transmission is a failure. This vehicle has a 3800 Buick Engine with a distibutorless ignition. The coil pack is well known to have breakdown problems as does the module. They tend to break down the spark "under load" and usually appears just above idle(2000rpm). Plug wires can also be an issue just as I said. If the vibration was constant and got monstrously bad the faster the engine revved, I'd say yes, the converter is the problem. The owner of the car says it's at 2000rpm(not the entire range) and only "under load(spark issue) accelerating(spark issue). Refusing to look at other issues that may be part of the problem is why so many shops get a bad reputation. Mine has an excellent one because I do look for any possible culprit. Nobody likes to accept that old parts do wear out. I had one customer who thought I should be responsible for her A/C because I fixed the ignition and fuel systems on her car. It came in on a rollback and left under it's own power. Her A/C is 15 years old. I am not the cause of A/C not working, it's old! It probably didn't work when it came in. As a good will gesture, I had a nearly new compressor laying around and gave it to her. The evaporator then came apart. She thought I should fix the whole system for free. Ummmm, no! Her car is old and everything I replaced was original equipment. Old stuff wears out and breaks. Jason should go ahead and have the module and coil pack tested and/or replaced(as a set) along with good wires. The slippage/chuggling is the tranny and/or the converter. The vibration is NOT!

You wrote The torque converter may be an issue, but it will cause vibration from idle all the way up, getting exponentially worse as the engine revs up. Unquote, Ummm, no it won't, the torque converter clutch is released untill you are in 3rd gear, it does not engage at any time the transmission is in any other gear than third. The vibration at the 3 to 4 shift is when the torque converter clutch (Overdrive) is attempting to engage, but because the oil pressure is low, it shudders while engaging, in other words the engine is forcing the clutch to slip and shudder when trying to engage.(Not enough force to firmly connect, so it shudders and slides when it tries to engage) See the clutch inside the torque converter is relatively weak, and to prevent engagement when the auto is under heavy throttle there are sensors that tell the car's computer if the vacuum is low (Heavy throttle) the position of the throttle (Throttle position sensor) as well as a speed sensor to tell about what speed the internal transmission parts are turning. Under heavy throttle the torque converter clutch is locked out, it cannot, and will not engage until the accelleration is lower (Pick your foot up off the throttle), so any vibration OTHER than the 3-4 shift is caused by the clutches within the transmission trying to engage.(1-2, 2-3 shifts) A vibration shifting from 1-2 is internal, NOT the torque converter clutch (It releases when you hit the gas), likewise the 2-3 also is internal, only the 3-4 shift is actualy the torque converter's clutch engaging, and only under reduced throttle. In short, the torque converter CANNOT be the vibration "At any speed" only on the 3-4 shift.

You wrote The torque converter may be an issue, but it will cause vibration from idle all the way up, getting exponentially worse as the engine revs up. Unquote, Ummm, no it won't, the torque converter clutch is released untill you are in 3rd gear, it does not engage at any time the transmission is in any other gear than third. The vibration at the 3 to 4 shift is when the torque converter clutch (Overdrive) is attempting to engage, but because the oil pressure is low, it shudders while engaging, in other words the engine is forcing the clutch to slip and shudder when trying to engage.(Not enough force to firmly connect, so it shudders and slides when it tries to engage) See the clutch inside the torque converter is relatively weak, and to prevent engagement when the auto is under heavy throttle there are sensors that tell the car's computer if the vacuum is low (Heavy throttle) the position of the throttle (Throttle position sensor) as well as a speed sensor to tell about what speed the internal transmission parts are turning. Under heavy throttle the torque converter clutch is locked out, it cannot, and will not engage until the accelleration is lower (Pick your foot up off the throttle), so any vibration OTHER than the 3-4 shift is caused by the clutches within the transmission trying to engage.(1-2, 2-3 shifts) A vibration shifting from 1-2 is internal, NOT the torque converter clutch (It releases when you hit the gas), likewise the 2-3 also is internal, only the 3-4 shift is actualy the torque converter's clutch engaging, and only under reduced throttle. In short, the torque converter CANNOT be the vibration "At any speed" only on the 3-4 shift.

You wrote The torque converter may be an issue, but it will cause vibration from idle all the way up, getting exponentially worse as the engine revs up. Unquote, Ummm, no it won't, the torque converter clutch is released untill you are in 3rd gear, it does not engage at any time the transmission is in any other gear than third. The vibration at the 3 to 4 shift is when the torque converter clutch (Overdrive) is attempting to engage, but because the oil pressure is low, it shudders while engaging, in other words the engine is forcing the clutch to slip and shudder when trying to engage.(Not enough force to firmly connect, so it shudders and slides when it tries to engage) See the clutch inside the torque converter is relatively weak, and to prevent engagement when the auto is under heavy throttle there are sensors that tell the car's computer if the vacuum is low (Heavy throttle) the position of the throttle (Throttle position sensor) as well as a speed sensor to tell about what speed the internal transmission parts are turning. Under heavy throttle the torque converter clutch is locked out, it cannot, and will not engage until the accelleration is lower (Pick your foot up off the throttle), so any vibration OTHER than the 3-4 shift is caused by the clutches within the transmission trying to engage.(1-2, 2-3 shifts) A vibration shifting from 1-2 is internal, NOT the torque converter clutch (It releases when you hit the gas), likewise the 2-3 also is internal, only the 3-4 shift is actualy the torque converter's clutch engaging, and only under reduced throttle. In short, the torque converter CANNOT be the vibration "At any speed" only on the 3-4 shift.

You wrote The torque converter may be an issue, but it will cause vibration from idle all the way up, getting exponentially worse as the engine revs up. Unquote, Ummm, no it won't, the torque converter clutch is released untill you are in 3rd gear, it does not engage at any time the transmission is in any other gear than third. The vibration at the 3 to 4 shift is when the torque converter clutch (Overdrive) is attempting to engage, but because the oil pressure is low, it shudders while engaging, in other words the engine is forcing the clutch to slip and shudder when trying to engage.(Not enough force to firmly connect, so it shudders and slides when it tries to engage) See the clutch inside the torque converter is relatively weak, and to prevent engagement when the auto is under heavy throttle there are sensors that tell the car's computer if the vacuum is low (Heavy throttle) the position of the throttle (Throttle position sensor) as well as a speed sensor to tell about what speed the internal transmission parts are turning. Under heavy throttle the torque converter clutch is locked out, it cannot, and will not engage until the accelleration is lower (Pick your foot up off the throttle), so any vibration OTHER than the 3-4 shift is caused by the clutches within the transmission trying to engage.(1-2, 2-3 shifts) A vibration shifting from 1-2 is internal, NOT the torque converter clutch (It releases when you hit the gas), likewise the 2-3 also is internal, only the 3-4 shift is actualy the torque converter's clutch engaging, and only under reduced throttle. In short, the torque converter CANNOT be the vibration "At any speed" only on the 3-4 shift.

I only mentioned the plug wires because Jason said the vibration is at 2000 rpm under load while accelerating. The torque converter may be an issue, but it will cause vibration from idle all the way up, getting exponentially worse as the engine revs up. Basic physics. Jason did not state that was happening. He said it does it at about 2000 rpm only and again, while under a load. Mixing up 2 wires will do this while allowing the engine to idle fine and cruise fine also. He did however, get screwed on the rebuild. All of the transmissions I build have very clean shifts with very little overlap, and in 15 years I have had only 2 come back. One was a seal and one was an owner trying to drive everywhere in 3rd instead of OD in his K5 Blazer. I have found over the past 25 years not to take anything for granted. If someone can mess up the job, it will be done. Always recheck everything before giving the vehicle back to the owner, even if what you're looking for should have nothing to do with the repair itself.

I'm also a Master Mechanic, and I completely agree with the post describing the torque converter as the vibration, but as the transmission is also slipping on the 1-2 shift, as well as the 3-4 shift (Overdrive engagement, the torque converter is slipping here) You have a poorly adjusted/rebuilt transmission.With low internal oil pressure. It's common knowledge (By Mechanics) that the harder any transmission shifts between any two gears, the LONGER it will last and the LESS trouble it will give. Let me restate that, a transmission that shifts with a HARD "Clunk" will last d**n near forever. A transmission that "Slides" into gear slooowly, will wear out quickly. See the only real wear is when the clutches are actualy in the process of engaging, and the longer they take to engage, the more wear, a quick (Hard) engagement wears very little, but a slow (Slipping) engagement wears out quickly. Based on the slow, slipping engagement you describe, the transmission needs to be rebuilt, with special attention given to the internal oil pressure (It's low) Get it rebuilt again, replace the torque converter, (Clutch inside is not repairable without cutting it open) and when you have a solid, hard shift, it's good. NOTE, solid, not at high speed, it should shift with a solid clunk at all speeds and loads (Less noticable at light throttle) DO NOT ACCEPT A SOFT SHIFT UNDER HEAVY THROTTLE

I see the posting about the crossed wires ~~this usually creates a situation of a stalling/stumbling engine or lots of vibration at idle~~as the person posted it was running "smoothly" i think that why no one said anything about crossed wires. THE TRANZMN

Thank you, thank you, thank you A hundred times more, THANK YOU Jason. Out of all the filings in these threads, you are the ONLY one to actually provide information, make-model-year-problem-etc. Everyone else puts down gibberish and then wonders why the mechs all crack on them. You put down the information required for assistance, and have gotten it. Tranzmn and Stevejj are both dead-on. I don't know what is up with John...bad day I think. There's one thing nobody mentioned though concerning the vibration. Check the firing order on the plug wires. Having a couple of them switched will cause the engine to shake like hell accelerating, but run very smoothly at cruising speeds. I know they have nothing to do with the transmission. This does not mean they didn't get switched around during the whole operation. I've seen goofier stuff. I told a guy to swap out engines on an Escort once. Within 4 hours, he had the entire car torn apart from the firewall-forward, including the transmission. The entire front clip was laying in the corner of the shop, in a hundred pieces. The engine was still in the car. It's also possible they used the wrong flexplate for the engine. That 3.8 went through a dozen changes during the years of development. I would not be surprised if they used one that was "laying around". Good luck.

4l60-e, i know this trans well,1870 is torque converter slipping,usually caused by worn tcc valve in valve body,or tcc valve in pump,have been a rebuilder for over 20 years,this shop should know this,with all due respect to ase you can get what the test is all about before you take it,its just another money thing, To find out more about this problem contact-trni,or atsg also there is a fix from sonnax to address these problems,these people dont know or are being conned by someone who claims to be a rebuilder.thank you ! Solution-dont know about your vibration, but a pressure gauge will tell you if your pump is working,also a tran-x which bypasses your computer will check all electrical solenoids which could be a factor also-good luck !

I have done the same thing and still do. Even though I know better. I was told by a person from the regulating agency in California. Quote:You have to nail them and document every thing wrong with their car,They are out to screw you, and we will help them.I personally have a policy of charging my family members lots more than my reg, customers. and since I have they are happy.One thing that you customers need to know, the dealer/Mfg make products that are not designed to last forever,My 2003 Toyota Tundras Differential just broke and the car only has 4000 miles on it. They will fix it? I believe that most of the complaints about automotive repairs are based on attitude.Mostly yours, most mechanics I've met in 25 years have nothing but respect for your ride. And they do their best to fix the problem.However you must understand we can only fix what we can confirm. I have been to court soooo many times, after trying to solve issues with the customer. even though i win im not happy. oh by the way the biggest problem in the auto repair industry is the parts they leave alot to be desired. If a new part fails that we installed and It destroyes our trans job those wonderfull people replace the part, Your out time we just lost all profit. But the gov. sees fit to protect them. And If they want they may sue me for my statement. However this is just my personal opinion.. To get to your problem, think how could I have solved this before it went out of control. Number one you are not telling the hole story, and your verson does not past the smell test. You know way too many ase certified mechanics. Since I hire them I found that few if any have any experience or for that matter ever actually fixed any thing. Im sure they passed their test with flying colors. Well im not saying that that or any other store did wrong , im sure they did not conspire to screw you, mistakes are made people should try to solve them when they occur. I have known people that will not. Hence court, one of my bad sayings is, (I did'nt make it, I did'nt break it. I'm just trying to fix it.and believe this or not sometimes customers lie I'm very sorry that your car is not fixed.I wish you a happy life, and also a very good extended warranty on your next vehicle. Or buy a toyota they never break!!!!!!!!!!!!!!!!

Jason`~~~~check this for vibration~~~park position~~~rev engine to 2000-3000 rpm steady an see if it vibrates~~~if it does ~~your torque conveter or harmonic balancer (front of crankshaft) are having a problem~~~~~also watch the waterpump pulley (while at idle) for wobble~~~~if all ok~~~~check driveshaft (front) u joint for play~~~if all ok~~~~do a pressure test (hot) your tranz may have a pressure loss that causes the foward clutch slip under load~~~~by the way a bent input (turbine) shaft would wipe out a tranz in less than a 100 miles~~~~~~~~~THE TRANZMN