New member, '86 K20, question

[Trenfrow328]

New member...1986 Chevy K20. 350/TH400. Bought the truck as a project for my boys and I to work on. Not sure how far we are going to go on the restoration, but I plan to rebuild the transmission and engine. One question I have...when I accelerate (somewhat quickly) and let off suddenly, there is a loud slamming sound (and you can feel it bang/slam) coming from engine area. Not sure if it is motor mount or transmission. I almost feel like the torque is twisting something, and then it is slamming back down if you suddenly let off accelerator quickly. I checked slop in drive shafts, and both U joints are good. Any ideas?
Thanks for any info...I am looking forward to learning from the forum.

Troy

 

[Ricko1966]

Welcome. Power brake it while you have a friend or one of your boys look over the fender. See if the engine rocks up.

 

[Shorty81]

^^^ this. Check engine mounts.

 

[Shorty81]

Welcome from Ohio. I have an 86 orange K20 also.

 

[Elliot W]

Not sure if its a Tacoma only problem, but my Tacoma has similar symptoms. Turned out to be axle wrap causing the driveshaft to move excessively in the slip yoke on acceleration/deceleration. It also doesn't help that the Tacoma slip yoke is only lubricated by transmission fluid (I've put grease on the splines before but the trans fluid washes it away). Maybe this is happening to your k10.

 

[animal]

 

[WFO]

Welcome from the Texas Panhandle.

 

[fast 99]

Broncos had that issue for some time. It was described as a bowling ball banging around in the back area. Ford produced special grease for it. There was a TSB.

 

[Snoots]

You must be registered for see images attach

 

[Strick]

Welcome! Check the engine mounts.

Strickland

 

[Elliot W]

Broncos had that issue for some time. It was described as a bowling ball banging around in the back area. Ford produced special grease for it. There was a TSB.

The Tacoma forums reference the ford grease and that what I used for my slip yoke but for whatever reason, this transmission seems to port the transmission fluid to the slip yoke for lubrication. So after applying the ford grease, it was wiped away after a few hundred miles and the grease is now likely mixed in with the trans fluid. The truck is a 2010 quad cab prerunner where the slip yoke goes to the transmission (as opposed to other models where the slip yoke is between u joints), and neither the slip yoke or u joints are greaseable with zerk fittings. I assume every other truck like this has this issue and I haven't seen a fix for it (as far as lubricating the slip yoke goes) except for installing traction bars that stiffen the rear axle and prevent axle warping. Apologies for the rant and hijack of the welcome thread...this has been a very annoying problem and is my only gripe with the truck.

 

[Mr Clean]

Sounds like motor mount, trans mount, or cracked frame at the steering box. Like mentioned already axle wrap due to bad spring bushings.

 

[wonderlander774]

Nice truck