1995 Blazer
I have been getting a thud/jerk when the automatic transition is making its 1st shift after starting from a dead stop. It does not happen all the time though.

Does this mean my transmission is going to give out?

Is there any additive I can put in to help this / condition it?

Just trying to get as much life out of it as possible.

 

my 98 does it after about 35 minutes of driving when its good and warm, in the snow or rain the shift from 1st to 2nd can send the truck sideways. I call it my shift kit lol i figure it's going, but at 300000 k im running on borrowed time as it is.

 

transmission mounts bad, replaced mine thud/ jerk was gone hope this helps

 

changing you tranny fluid and filter may help if not change tranny mounts if that dont help drive it till she goes then salvage yard your year and low miledge save ya hundreds goin to the salvage yard!

 

I think I am having the same issue if I am correct.

Our Blazer gives a light thud/jerk when shifting from 1st to 2nd gear, both when warm and cold. It doesn't do this or is not noticable when accelerating normally or slowly. But when I push it a little harder, it gives this slight thud which the higher gears don't have.

I also have a Audi with brand new 7-gear-automatic and all gears are equally smooth. But this is of course a brand new gear box. Our chevy has about 66.000 miles on the clock.

Is our first gear bad? I still have warrenty right now, so I want to know for sure. Can I check this?

 

Don't really know if it's just a coincidence, but mine was doing the same thing. I took off the MAF and cleaned it and I've never had the problem since.

 

thanks, I'll check if the MAF is dirty.

any other tips?

 

Also check your connections going to the PCM. We bought my 98 in November 2007 and the tranny was shifting harsh, the front axle shift fork was broken and some other stuff. It set a DTC related to it. I managed to clear the light using the brake pedal trick, but the code was still in the computer. The GMC dealer replaced the shift fork and a transmission solenoid. GMC set us back over $1200. The jerk continued until May 2008 when I noticed a loose electrical connector on the PCM when I was checking the oil. I reseated the plug. A couple hours later I was going to the school band concert I had to play in and the whole way it didn't shift hard once. I was bracing for the 1-2 shift after pulling out of the driveway to shake the car like usual, but the jerk didn't happen. NEVER had another hard shift since. There are 4 plugs on the PCM. Make sure they are all plugged in correctly and that there is no contamination on the contacts. If one of them is loose, you might have just found your problem. Good luck.

 

Did you manage to fix your problem? Just curious.

BD

 

I have been having troubles along the same line.More so once it has warmed up.Mine is a 97.The other day we were coming home and without any warning the service engine light came on.I did the obd2 scan thing and come up with a P-1870.Something is slipping.Everything I have learned thus far indicates the TCC valve.The transmission fluid looks dark and has a burnt smell to it.The friend I bought it from said....oh yeah...they used to tow BIG boats with it.Now what?