Tranny Problems......

[Cable]

Hey guys, I am having alittle problem with my TH350 in my little 454 powered Datsun. About a week ago I starting hearing a slight squeal around 2000 RPM while cruising and in all gears. I thought it was just the alt belt slipping. I replaced the belt and then removed the belt and the noise is still there.

 

Then on Saturday I did a 3/4 thottle pass for about 10 seconds. Afterward I can really hear the squeal and it is loud. I popped the tranny into neutral and the noise is gone instantally. It only does it in gear (including reverse) and stops the instant it is in park or neutral. Its really loud between 1000-2000 RPM and gets alittle quieter as RPM increases.

 

Yesterday I chocked the wheels and engaged the e-brake and put the car in gear and then tried listening for the source. The noise is not coming from the motor. It shifts fine and there are no other issues when driving. I checked all flexplate bolts and the fluid is clean.

 

I had the tranny looked at 500 miles ago, and everything was great. The converter is a used piece I bought from another member. Its a 10" unit and seemed to work fine.

 

I talked with a few guys I know and they think its one of three things.....

 

1. Converter

 

2. Front Pump

 

3. Sprag

 

I am curious to know what you guys think.

 

Any help is thanked in advanced.

[jakeshoe]

Does it only do it when moving or anytime it is in gear?

 

If it only does it when moving. but does so in any gear, it is probably in the rear geartrain.

 

If it does it all the time except in park or neutral, it is likely a pump issue. The pressure is exhausted back to the pan when in neutral or park. So the pressure at the pump is reduced and would cause the noise to stop.

 

Is it a squeel or a buzz.

 

A buzzing sound can be the pressure regulator shuttling from air on the fluid (loose filter, plugged filter, low fluid, etc).

[Cable]

It only does it in gear, moving or sitting in place.

 

It is definately a squeal, almost like a belt slipping.

 

I have been debating on going to an overdrive anyway, I might go that route soon anyway. After reading a recent topic that you posted in, it looks like the 4L80 would be my best course. I don't want to run a computer and I've heard there is a way to set it up that I will just have to manually shift it, is this correct?

 

Besides shorting my driveshaft, what else is required for the swap?

 

Thanks for you help!!

[jakeshoe]

4L80E requires either a control unit or manual VB, tailhousong for mechanical speedo, converter box, or electronic speedo, shortened driveshaft, crossmember mods, and 4L80 specific converter.

[Guest Mike]

Yeah, but it's one helluva tuff transmission, right

[Guest timmy72240]

run it till it breaks or explodes thats what i would do...bro you will probably have a cool story to tell also....

[Ledphoot]

if budget allows OD is nice. But it is hard to beat a good old th350-400 Good trannies and easy to get rebuilt. Definately sounds like a front pump. Might as well yank it and get it rebuilt for a few hundred bucks. If you dont know someone who can do it cheap, just walk up to the Chevy dealer shop bays at lunch time with a quality kit, the tranny and $100 bill and a pint of Crown, most guys around here will jump on it and have it back the next day.