My Tranny is "Jerking Me Around!"

buick
century
transmissions

#1

I can’t get the dropdown menus for selecting vehicle make and vehicle model to work for me here, but I recently had the automatic transmission in my 2000 Buick Century 3.1 Liter replaced with a used one with~80k miles, by a local shop. A rebuilt would have been much more costly. The upshifts are perfect. But sometimes when decelerating then reaccelerating soon, it will slip then jerk quite strongly. They had replaced the fluid with Dex6, and the filter per the invoice, and The fluid level is well in range on the dipstick after I checked per owner’s manual instructions. I’m thinking they didn’t say anything about their 12 month/12,000 mile parts & labor warranty since this is a used transmission, I would assume I bought it “as is”, and it is not covered by their warranty. Their diagnostics are not free, a $100 fee. I left them a voicemail attempting to find out about if possibly their warranty would cover this used tranny, but before I would be able to actually talk to them them about this, might anyone know what would likely be happening with the tranny?


#2

A used transmission might come with a short–perhaps 30 day–warranty, but I seriously doubt if any shop would give you a 12 month/12k mile warranty on a used trans that might not have had any maintenance from its previous owner.
But, rather than speculate–what does the shop’s invoice state, regarding a warranty? If it mentions nothing about that issue, I wouldn’t assume anything longer than 30 days, and perhaps it has no warranty.


#3

I expect the used tranny was doing this too, in the car it came from. It probably was obtained from a wrecked car so the recycler didn’t realize it had this problem. So no harm to ask the installer about this. They may well just install another used tranny for you. If they won’t, then maybe doing a few proper services would help. That means to drop the pan, clean everything you can, replace the filter, refill with fresh fluid. Drive for 100 miles, then do it again. If this helps but doesn’t entirely solve the problem you may have to repeat this a few more times. Basically you are cleaning the other fellow’s transmission on your dime. But this is a chance you take with used parts.


#4

At $300 per transmission service it would have better to have had the transmission rebuilt to achieve the shift quality desired, having a 19 year old transmission service 5 times is a waste of money.


#5

It’s a compromise.


#6

Thanks for replies, fellows. The mechanic called me back yesterday, Friday 11/2/18, said there is a 30 day warranty on this used trans, as you have said,VDC driver. The invoice stated a 12 month/12,000 mile whichever came first warranty but of course that was for new parts. He will give it a test drive later this morning, Saturday 11/3/18. He had said something about driving it a short time then having a trans fluid change done on it again to clean it out, he probably meant to purge the DEX3 that was probably in this used tranny. If I have to keep doing fluid changes, makes me want to fit up a drain plug in the pan so I don’t make a mess next time dropping a pan full of trans fluid.I could drill a hole, solder in a 1/2 “IPS brass threaded bushing with a 1/2” EMT conduit locknut holding it secure inside the pan, having cut off the narrow part of the pipe thread first, and put a low profile allen head 3/8" IPS brass plug in the bushing. I always thought it would sure be nice if transmission drain plugs were put in by the factory like the oil pan has a drain plug.


#7

Good point. I’ve always wondered about that. Perhaps there’s a valid reason the manufactures don’t install drain plugs in the automatic transmission pans, but include drain plugs in their manual transmissions. The only reason I can think of is that to properly do a drain and re-fill on an automatic the bottom of the pan needs to be cleaned out, due to add’l debris generated from an automatic vs a manual.


#8

But I just meant to first get the fluid drained out by removing plug, then unbolting the pan and wiping out the sediment…
And the mechanic did ride with me Saturday for a test drive, and of course being an intermittent problem, it didn’t show itself for him, just slipped a bit. But after he left, of course it slipped and slammed, and did it Sunday morning once also…