I have a 1988 Chevy Blazer K5 350 and it runs good and starts good when cold but when I put it into gear it really hits hard and wants to jump because the idle is high due to it being cold.Ihave to make sure my foot is on the brake pedalreallyhard to keep it from jumpingforward but it does not move just jerks really hard. It does not do this when warm....runs just fine. I don't remember other trucks I have had doing this. Is this normal or what?

Thanks for the help.
Doug

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Umm low on trany fluid? I would first look at the oil level in the tranny cause it sounds like its jumping the clutch once it gets to that trigger point instead of slowly engaging as the rpms increase. That or your rpms are simply too high which is making it jump into gear.

 

You had a previous post about stalling cold (possible vacuum leak). Did you fix this problem?
I'm just thinking that the 2 problems could be related and caused by the same problem.

 

My 1995 blazer did the same thing and my foot had to smashed to the floor with the brake. i fixed the problem but changing the tranny fluid and filter and its all good now. give that a shot and see what happends. doesnt take too much time at all.

 

I have not had a chance to repair the possible vacuume leak, it's just been way too cold and raining and snowing to do any work on the Blazer. I still need to check that. The tranny flud is full on the stick but do not know about the filter. I will try looking to see if the vacuume leaks first and if that does not work I will get the tranny serviced. Thanks to all. Any other comments welcome.

Doug

 

What transmission is in the truck? If it is a Turbo Hydromatic 350 your vacuum leak and transmission lurching maybe the same problem. With the older TH350s they came with a vacuum switch (vacuum modultator) and if this is leaking vacuum then it could cause the idle to be elevated and cause hard to get into gear...You should check to see if there is a vacuum hose label in the engine compartment to find the hose that connects to the transmission vacuum modulator...

 

Thanks, you guys are the kings! I'll look at that this week!

Doug