HELP 200-4R - atf spraying out pass side on hard accel only

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CamaroMan

Not-quite-so-new-guy
Thread starter
Nov 15, 2021
16
3
ok major update - wife and her ear muffs had the bore camera down there and within SECONDS at 30mph the servo was spraying fluid out around the 11 oclock position


this within 15s of mostly idling and a small buzz...

is it the large oring? could that much fluid be going behind the oring? that seems a little too much to handle no?

servo-leak-2004r.jpg
 
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melloelky

Comic Book Super Hero
Oct 22, 2017
3,767
113
mass
wow that's something.nice job figuring it out..that's a good woman you got there.
 
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81cutlass

Comic Book Super Hero
Feb 16, 2009
4,309
113
Western MN
Is the case clean where the O ring seats?

Good find
 

81cutlass

Comic Book Super Hero
Feb 16, 2009
4,309
113
Western MN
Never had a leak with prev servo.. could an incorrectly assembled 2-3 acc cause this? Just nitpicking possibilities here..

Not sure functionally, but a proper O-ring or square seal should hold north of 3000psi. The trans pump puts out maybe 300psi. You found the leak was coming out of the top. Can you remove the servo and turn it 180 degrees and see if the leak stays at that position or moves relative to the servo?

My bet is a sight score in the housing, bad tolerance/design on the servo, or a seal that's nicked or something out of spec.

NEW means never-ever-worked ;)
 
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64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
4,967
113
Upstate NY
Very curious of your line pressure. I would guess a machining tolerance/bore issue though as described above.
 

CamaroMan

Not-quite-so-new-guy
Thread starter
Nov 15, 2021
16
3
Got this response from sonnax tech:

"From your video it’s hard to establish if the leak is coming from the servo cover (I replied it def was leaking from the servo cover). You can check it relatively easily by running it on lift while power braking it, shifting it from manual 1st to manual 2nd with someone watching underneath. I would assure it’s up to operating temp and then you can use power braking to simulate load. In our experience when 2004R sprays ATF out like that is usually a pump issue. I would be interested in looking at pressures on this under max or heavy throttle. It’s possible the pump may be cavitating or losing prime under high/heavy throttle."

Ill rig up a test gauge today if possible and get some numbers - got a busy day at the shop tho.. this is the 2nd pump that did this, i swapped it out at last build for a 2nd gen one (without the grooves in front seal - but i cut grooves like the late style on the lathe) - everything else is stock OEM 7 vane with the drain back hole mod and spring/tv/line pressure upgrades from sonnax-
 

CamaroMan

Not-quite-so-new-guy
Thread starter
Nov 15, 2021
16
3
Very curious of your line pressure. I would guess a machining tolerance/bore issue though as described above.

What could cause excessive line pressure? my original pump (had no issues for thousands of miles) did the same thing - i swapped pumps thinking i messed sth up back to a stock OEM 7 vane- same issue... ATF puking out the side..

sth else - all I did was shim tolerances tighter, art carr shift kit, sonnax 2-3 accumulator and servo kits, and pump upgrades -
 

64nailhead

Goat Herder
Supporting Member
Dec 1, 2014
4,967
113
Upstate NY
What could cause excessive line pressure? my original pump (had no issues for thousands of miles) did the same thing - i swapped pumps thinking i messed sth up back to a stock OEM 7 vane- same issue... ATF puking out the side..

sth else - all I did was shim tolerances tighter, art carr shift kit, sonnax 2-3 accumulator and servo kits, and pump upgrades -
Do you have the original servo cover?
 
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