Noisy 66

[bluechevy66]

I have noise in my 66 I need help with. Here's the situation... I pulled a 12ft trailer yesterday with a medium load at around a 70 mile trip. I noticed it bogging down quite a bit on hills and idling funny at stops. But when I got home to unload the stuff, I heard a sort of clanking, where I think, was coming from the rear end... MAYBE. Also, the motor acted like it got too hot... idling and noisy lifters. Here's what I have in it. I have a gm goodwrench 350 crate motor with about 2000 miles on it, I just converted it to a th350 used auto trans. The drive shaft has all new u-joints. The only thing I'm not sure about is the differential... I don't know if it's original or what the gearing on it is. I do know it has a chrome cover, so someone has at least replaced the cover. Now, the tranny is still shifting smooth and the motor starts right up and idles fine since it's not hot anymore. And after driving it today without a trailer, the clanking has gone away. Plenty of fluid in the rear-end. So, my question is, does the clanking while hauling a load sound like it might be something wrong with the differential? Like I said, it's not clanking now, but was when driven long miles with a load. I'm assuming the tranny is ok since it was shifting smooth even while hot... but then again, I know nothing about transmissions. All the oils are full and look great.
Any help would be great!

[kieth]

Originally Posted by bluechevy66

I have noise in my 66 I need help with. Here's the situation... I pulled a 12ft trailer yesterday with a medium load at around a 70 mile trip. I noticed it bogging down quite a bit on hills and idling funny at stops. But when I got home to unload the stuff, I heard a sort of clanking, where I think, was coming from the rear end... MAYBE. Also, the motor acted like it got too hot... idling and noisy lifters. Here's what I have in it. I have a gm goodwrench 350 crate motor with about 2000 miles on it, I just converted it to a th350 used auto trans. The drive shaft has all new u-joints. The only thing I'm not sure about is the differential... I don't know if it's original or what the gearing on it is. I do know it has a chrome cover, so someone has at least replaced the cover. Now, the tranny is still shifting smooth and the motor starts right up and idles fine since it's not hot anymore. And after driving it today without a trailer, the clanking has gone away. Plenty of fluid in the rear-end. So, my question is, does the clanking while hauling a load sound like it might be something wrong with the differential? Like I said, it's not clanking now, but was when driven long miles with a load. I'm assuming the tranny is ok since it was shifting smooth even while hot... but then again, I know nothing about transmissions. All the oils are full and look great.
Any help would be great!

Check the fluid level for the oil in the rear end.....it could also need to be changed......????

[donthekawguy]

Grab the pinion where it connects to the driveline and give a good shake. The bearings could be worn or the pinion could be worn out.

[bluechevy66]

I was just thinking bearings... I notice the clank in neutral at a very slow roll today.

[MARTYZ]

I am thinking possibly u joint or hanger bearing if noise is there in neutral roll

[TJ's Chevy]

I would pull the cover off and see what your carrier looks like...We blew the spider gears in Dad's 77 chevy..now that's a 14 bolt....and it would clank and the driveshaft would jump...and in sharp turns it would clank alot...but..it gave us an excuse to put in a posi unit. lol.

[donthekawguy]

When you figure it out make sure to let us know what it was. And if anything is broke pics are a must!

[bluechevy66]

Ha ha! You got it... Pics for sure. Thanks for all your responses. I did check the oil and it's good on the level, but I have no idea how old it is. You've all given me a good place to start looking. Now, just need to find the time!
One more question about the differential. If my problem happens to be the rear end, what's a good gearing to replace it with for lower rpms? Like I said, I'm running a 350 with a th350 tranny.

[cortcomp]

Well with a 350, if you don't mind losing some take off torque, i wouldn't think 3.42 unreasonable to still pull some loads with. If it will be heavy loads and hills, you still need that 3.73 rear (assuming 3.73), so better to drop RPMS with like a 700R4 so you don't sacrifice take off and pulling power.

[AcampoDave]

How are the control arm and panhard bar bushings? Could it be the extra load caused them to bang around?

[65c10restomod]

might be the trans over heated