700R4 Pump Noise - Options?
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Joined: Feb 2007
Posts: 155
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From: Mississauga, Ontario
Car: 84 Camaro 2.8L, 85 T/A 305 LG4
700R4 Pump Noise - Options?
My I am getting a relatively loud knocking/tapping noisefrom the belhousing of my bone-stock 85 T/A with 305 LG4 and 700R4 automatic.The car has about 70,000 miles on it and has been driven pretty gentle most ofits life. The noise is intermittent, butmore common and louder when the air temperature and car is cold. When theweather is warm, or the car is hot the sound either disappears or isdramatically reduced. The noise does change frequency with rpm and when it’spresent it can be heard in all gears (including park and neutral)
I originally thought it was a flexplate, so while I had itat my mechanics for some other service I asked him to look at it. He reportedback that the flex plate and torque converter were fine, but that the sound wasmost likely coming from the front pump in the transmission.
Other than the noise the car drives fine; no shifting issuesor lag engaging.
The fluid looked fine (red, correct level) but I decided tohave it changed anyway while it was at the shop. The tech said the pan wasreasonably clean. The new filter and fluid did nothing to change the noisethough.
So now my question is; assuming it is the pump, can the pumpbe replace/rebuilt without rebuilding the entire transmission? Or should thecomplete thing be rebuilt?
I originally thought it was a flexplate, so while I had itat my mechanics for some other service I asked him to look at it. He reportedback that the flex plate and torque converter were fine, but that the sound wasmost likely coming from the front pump in the transmission.
Other than the noise the car drives fine; no shifting issuesor lag engaging.
The fluid looked fine (red, correct level) but I decided tohave it changed anyway while it was at the shop. The tech said the pan wasreasonably clean. The new filter and fluid did nothing to change the noisethough.
So now my question is; assuming it is the pump, can the pumpbe replace/rebuilt without rebuilding the entire transmission? Or should thecomplete thing be rebuilt?
Joined: Jul 2000
Posts: 6,522
Likes: 92
From: Aridzona
Car: `86 SS / `87 SS
Engine: L69 w/ TPI on top / 305 4bbl
Transmission: `95 T56 \ `88 200-4R
Re: 700R4 Pump Noise - Options?
Unbolt the 3 bolts holding the converter to the flexplate.
Push the converter back.
Start the car.
Noise gone? It's the pump.
It can be replaced by itself with correct tools & procedures.
Push the converter back.
Start the car.
Noise gone? It's the pump.
It can be replaced by itself with correct tools & procedures.
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