Where does my TF727 oil leaks from?

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Topic author
letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Where does my TF727 oil leaks from?

Post by letank »

EDIT: for the TF727, Yes, it has to leak , but there is no puddle under the jeep when it sits overnight, or after 2 days.
I had a good 450 miles trip last weekend, the only casualty on the way in, to south lake tahoe being that the windshield washer pump quit, while being in snow country it was a pain for 30 min without good visibility until I found the local parts store and bought a washer pump.
Yes, I could smell something on the steep climbs, but thought that some old oil leak was being cooked up.
So.... on the return trip there were a few clunks going up the Echo summit on Hwy 50, but it was gone when I slowed down, 50 miles later during a severe downpour, clunk and the speed drops to 40mph.... aaaaack, activate emergency lights, pull to the emergency lane, the engine is still running and the speed resume upon acceleration, keeping up at 40mph and even 45mph, pick the first exit after 1 mile, it is is still pouring cats and dogs, but lucky me, there is an overpass where I managed to park, check the transfluid level, engine running, in neutral, dang, no oil on dipstick.

Turn off engine, put overall, headlight, get oil, remove dipstick which now shows oil at full, pour 1 quart, restart engine, shift to all gears and Reverse, it is a bit low, add another pint, level is about right between full and add 1 pint, yes it has been cold and the trans temp never went above 110F

Somebody stops.... yeaaaaah, a sporty mercedes coupe, the driver, a woman dressed for a party ask if I need something..... "blank", be serious, "blank", "thank you for stopping if it does not work", it will be towed to your home.... nah, "it will be towed "

Uneventfull remaining 100 miles back to SF... I pushed the rpm and the speed, no clunks, no puddle under the beep, I added a dye, ran around the block, ready to go under later in the evening to see if I can spot some UV emitting dye...

I did a search and could not find anything conclusive beside a leaky front pump, but I really have no drips... the pan looks a bit coated by oily residue so is the rest of the undercarriage
Last edited by letank on Fri Mar 15, 2019 8:44 am, edited 2 times in total.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

will e
Posts: 5096
Joined: Sat Aug 18, 2012 8:21 am

Re: Where does my transmission oil leaks from?

Post by will e »

Check the vacuum lines. See if the oil is getting sucked into the engine.
81 Waggy 'WILL E' Retired
82 Cherokee WT - SOA/SF/high steer/Alcan springs/agr box/Borgeson steering shaft/AMC 401/performer/holley TA/HEI/BeCool/727/ALTAS (2.0/2.72/5.44)/D60 Snofighter(Yukon Zip,hubs,stubs,4.56)/14 Bolt (FF,BF shave, Discs, ARB,Artec Truss)/MTR 37X12.5/Corbeau XRS Baja & 5 point retractable harness/Hella Aux lights/tuffy console/killer32 sliders/Evil Twin bumpers, rack and roll cage/WARN 8000/TT Fabworks steering brace/dual batts/custom TC skid plate/ARB fridge

Topic author
letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Where does my TF727 leaks from?

Post by letank »

will e wrote:Check the vacuum lines. See if the oil is getting sucked into the engine.
Thank you, I forgot to add that it was for the 85 so this is the TF727. Indeed for the TH400 the modulator sucking up ATF thru the vacuum modulator is an excellent idea, it will reveal itself by the large cloud of white smoke on start up when the vacuum is at max.

I took a peek last night and the dye seems to be coming from somewhere above the rear intermediate adapter to the transfer case np229 ... the pan gasket has some minor dye on some bolts, but I have the reusable gasket, I guess I should have wiped it to see if there was some dye... it was too late to be awake when I thought about it... will redo in the evening.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

Topic author
letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Where does my TF727 oil leaks from?

Post by letank »

A week later and still no puddle in the street.... my best guess is that the cold temperature of the trans fluid, it was barely 30F during that mountain trip and the transmission temp never went over the 110F-115F range. So the level was probably lower than needed and during a few power run in 2nd gear to some of the grades, the trans fluid probably foamed up and got expelled thru the vent. When I stopped to check the fluid the trans temp was in the same temp range of 120F.

I will make a bib to cover part of the grille and have it handy for the next cold weather trip...
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)
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