Tranny shifts hard into drive

[tjslawny]

Just picked up an '86 Blazer - i love it... its got a 350, TH700R4 tranny. When I shift into drive, it shifts pretty hard - kinda jerks the old blazer - is this normal for the TH700R4 tranny? its got proper fluid levels. any ideas?

 

[Can Can]

First of all, brother, do us a favor and fill in your profile. Your location is important- one of us may live a couple of blocks away!!!

Now, how hard is hard? My 84 kicks pretty good going into either reverse or drive. It might be worth it to crawl under the truck and take a close look at all your u-joints and make sure that there's no extra play in your driveshaft. I have a feeling it's just an issue if you getting used to your new truck!!!! /forums/images/icons/wink.gif

Anyways, welcome to CK5!!! /forums/images/icons/smile.gif

 

[79Beast]

Check your idle speed. A high idle will have the same effect as gently holding your foot on the gas while shifting into drive or reverse. The idle speed should be listed under the hood on a sticker. If it isn't then 600 to 750 RPM is good for a stock SBC.

 

[dyeager535]

yep good point. Don't forget, not waiting for the choke to kick off will keep the idle up and "bang" into gear also.

Neighbor has a C20 that must fast idle at 2000RPM, and it hurts *me* to hear it put in gear immediately after starting it.

 

[77Jimmy]

I think I have the same problem -- a high fast idle and a big clunk. My choke never seems to kick off though. How long does it take for the choke to kick off? I think my choke is hosed b/c it is always open, but I've seen some other posts where some people purposely have their choke open all the time. Thanks.

 

[dyeager535]

Mine will allow me to kick it down right after starting (the way I set it) but typically by the time the temp gauge needle starts to move, the choke should be off.

If its always open then something isn't right obviously, work that issue until you get it solved, and then you can mess with fast idle speed and how soon the choke is open.

Obviously, outside of injection, you are going to have a problem with the choke (if you use one) and high idle when the vehicle is cold, and short of a manual tranny, letting it warm up, or adjusting the choke so it kicks off early, is the only way to avoid that.

One thing I've noticed though, is that even when set to kick off early (via the choke coil) the thing will reset itself with throttle application, until it does warm up more. I might be able to tune that out, but I'm not gonna spend more time on my carb setup.