700R4 4th Gear Noise

[Budget63]

Hi All,

I'm being told by the shop that my truck is at, that my transmission (700R4) makes a whining noise, and only in 4th gear. Any ideas on what could cause it? I searched and didn't see any threads regarding a noise like this in a 700R4. For what it's worth, It is a low mileage transmission, that has been stored for close to 2 years in my garage. It was just installed in the truck along with my engine, and the original drive line that was rebuilt and modified to fit (truck originally had a powerglide). They added a new filter and all new fluid while it was being installed. I haven't heard it myself, I'm just going off what they've told me. They also say it shifts just fine, with no other noises.

Thanks for any input!

[Clyde65]

Did you inspect before install? Two years is a long time to sit

[Budget63]

I did not, I don't know what I would be looking for. I only know the fluid looked clean.

[rvrfoot]

I would not know what to inspect one myself. There are many trans rebuilt seating on shelf ready to be installed for a long time.

[vince1]

I don't think sitting on a shelf has anything to do with it.

I have only rebuilt a few transmissions, none of them GM, but on one I remember a very worn out bushing where the sun gear shaft goes into the planetary gears. I would think that something like that would surely cause a whine, but shouldn't happen on a low mileage transmission.

[YoungPup1977]

Does the noise go away when the TCC engages ? Noise only in 4th gear ? Maybe take it to another shop for a second opinion.

[GASoline71]

Is the TV cable set up correctly? A cable that is not set correct can toast a 700R4 pretty quick.

Gary

[YoungPup1977]

In the first post it indicates that the transmission "shifts fine" so that ruled out the TV cable from my view point and yes, if the TV cable is not set correctly on a 700R4 it will have ill effects on the transmission.

But what I am hearing it has a noise ONLY in 4th gear....we need a better understanding of what the noise sounds like..... bearing noise ?
If a torrington bearing/planetary is making noise it will show itself soon, keep driving it and I am sure it will produce metal....... GOOD LUCK !

[Budget63]

Thanks all, for the input so far! I was just updated about the truck, and it turns out it's the rear end after all. I had the Yukon 5 lug kit installed using factory gears, and that's what the shop now thinks is the problem. So now we are looking at a Ring and Pinion and install kit. The truck currently has the factory 3.73's. They are recommending the US Gear Brand for the ring and pinion. Any thoughts on them? The only ratio I see on Summit from them is 3.42. I know this will yield slightly better mpg, but will I notice a loss in acceleration from going from 3.73 to 3.42?

[vince1]

I've had three Astro vans and I think they had a version of that transmission with 3.42's or something close. If you are doing any highway driving I think it would be OK.

[rvrfoot]

3.42 is fine with the 700r4

[YoungPup1977]

rear end noise would normally be present in all gears but more noticed in 4th.....I can see how some folks would get confused why only in 4th gear you would have Noise....

I have 3.42 gears with a 700r4 in my 1972 cheyenne which works really nice. Enjoy !