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700r4 noise

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3.9K views 12 replies 5 participants last post by  slingslingbinks  
#1 ·
Now that I've made some of the tools for working on the 700r4 and with the help from Trannymike I worked on one that needed a different output shaft to work in a 4wd and found a mess from a transmission shop that I found has a bad reputation for doing shoddy work. I've decided to go ahead and pull the tranny out of my 1983 C10 to find what is causing a ratching noise once you put it in gear(no noise in park) so I ask what do you think is causing the noise?
 
#7 ·
Maybe later, i see your off line now. I was wondering if the trans work's correctly and all gear's and engine braking work's or not. I'v seen where the stator inside the torque converter rub's in the impellar and make noise. This would only make noise while in gear and in park and neutral the input shaft is not being held so the impellar spins with the converter.
 
#8 ·
slingslingbinks,

I have a similar issue with my 700. It makes a "popping/flexing" noise only when in gear (fwd or reverse) and its always louder when the trans is under load. Once the rpm comes up and theres less load on it, it lessons until I let off the gas and it stops completely. Very confusing- It sounds like when you flex the sides of a soda or beer but the volume varies with the load. I have inspected the flexplate several times, as it sounded similar to a cracked one I had in the past. There are NO cracks in the flexplate. I'm inclined (hoping) it's coming from the convertor. I have a new B/M convertor just waiting to be installed.

TrannyMike- What is your professional "educated" guess?
 
#10 ·
OK guys, I've missed this thread somehow looking at the original date. Are you guys absolutely sure it's coming from the front of the trans? I was almost fooled once by a noise like this. I'm guessing here because noises are the toughest for me to diagnose on the internet. I would look to see if you guys have an aluminum driveline. The aluminum drivelines are 2 piece, with a rubber insert in between where the two pieces come together. I've heard those slip like a chatter that is VERY deceiving, and fool the best mechanics. It's pretty loud too. I know it sounds crazy, but it may be the problem. It's a metal tingy noise that can sound like a ratchet. It barely moves a little at a time, only a few thousands of an inch each time it makes the sound. So when you look at it, you don't see anything happening. :beer:
 
#11 ·
I started it up today to move it to work on it and I'll be hanged if the damn thing makes the noise as soon as it starts.
I thought maybe I had a broken cage on the sprag but since it makes the noise no matter what, in gear or not, maybe it's the flexplate but it shouldn't be I put a heavy duty flexplate in when I put the engine in and that was about 4 months before I had the tranny done.
Well I guess I'll just have to find out when I get a chance to dig into it.
Any other possibilities for the noise I'm listening it gives me a place to look and by the way my driveline is steel with Spicer u-joints new with the engine also and no play.