SM465 Transmission Noise

[DuallyK5]

Yeah I just currently installed a sm465/np205 combination into my k5 blazer. I got it all back together and running and driving yesturday. When i was driving it i noticed a slight grinding feeling in the shifter when i tapped the gas a bit. I had a 383 stroker motor so it does have some power when i hit the gas. Its fine when im driving no grinding feeling but if i tap the gas a bit and let go quickly i can feel a little grinding. can anyone possible tell me what the problme might be. It shifts perfectly fine with no grinding or anything and the shift pattern is tight. the fluid level is right where it is supposed to be. Also when installed the new pilot bushing in the crank it went in a little further then flush wiht teh surface of the crank. Is that bad could that be wats causing this noise?

 

[Hogback Fabrication]

Its probably the 205 that is making the noise and it is probably from a slight driveline vibration.

 

[DuallyK5]

um

My k5 doesnt have a lift really. It just had like 30 inch tires and the driveshaft is brand new i i really thing its coming from the tranny. And what would make the 205 make noise like where would teh noise possibly be coming from and is it bad to drive the vehical with the noise happening when u mash the throttle? like i can hit the trottle and it will be fine until i let off then it like slitghtly grinds. and it doesnt sound like a driveline vibration i mena i got a brand new driveshaflt and brand new yokes and brand new u joints so i doubt it is it. 1350 series stuff.

 

[goldwing2000]

It's probably a combination of the 205 and the gears in the rear axle.

When you let off the throttle, you unload the gears and it makes the contact pattern go from the front side of the gears to the back side of the gears, which are less worn and generally not as smooth. Besides that, an SM465 is normally a little noisy and a 205 is noisier than a chain-driven case. It's the price you pay for beef.

Just the nature of the beast. I wouldn't worry about it.

 

[DuallyK5]

ok

Ok thanks alot man. I have another truck that had a 8 inch lift with 38.5 boggers and that only has a stock 350 with edelbrock performer intake maniflord and a holley 670 truck avenger carb with holley mechanical performance fuel pump and a mild cam. That has the sm465 with the np208 right now and i am going to be changing that to the sm465 np205 combination once i get the coupler and adatper along wiht the crossmeber. I never have driven in a truck wiht the sm465/np205 combination so your probly right that what you get for going beefyer. Ill see what happens and thanks for the advice.