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Leak behind the transfer case, need some advice from the experts.
Hey Yotatech, I'm in need of some advice from the experts. Currently have a bunch of fluid over a whole bunch of stuff on the underside of my truck just rear of the transfer case. It is a clear and not smelly substance, it's covering a large portion of my fuel hardlines, along with a portion of the transfer case. It's spread out in such a way that it's almost like its being sprayed from something. (No its not water). Because it doesn't smell like anything strongly, and it's clear, i do not believe it is the transfercase leaking, so i think it's a fuel (diesel leak) coming a hardline.
So my question for you guys is what is the easiest way to fix this? Could i cut off a section of the hardline and replace it with a soft line? Or is it more complicated then that? My plan would be to overlap the existing hardline by at least 2 inches on either side with high pressure clamps per side, and throw an even bigger peice of fuel line over the smaller one, just to protect against any rocks or things from being shot up against it.
Id start by cleaning everything thoroughly, maybe car wash pressure washing it. Then keep a real close eye every time you drive to pinpoint where its coming from.
If it were a fuel line leaking, youd probably have some serious performance issues.
Id start by cleaning everything thoroughly, maybe car wash pressure washing it. Then keep a real close eye every time you drive to pinpoint where its coming from.
If it were a fuel line leaking, youd probably have some serious performance issues.
Every once in a while, i get decently bad misfiring issues, like a few times a month. When in low rpm's it skips a beat quite a bit, but it always goes away.
I've already washed it and it has come back, still unable to directly pinpoint where its coming from though.
This is a diesel you said?
i know that the gassers have a fuel pump relay you can jump to test. Maybe see if theres a way to run the fuel pump while being safely under the vehicle to see if youre leaking fuel.
there should also be a way to test pressure on injectors. If they were all significantly lower than spec, that would be a good indicator.
im also assuming you have a return line, which is probably less pressure. you could have a leak here which would be harder to test for
This is a diesel you said?
i know that the gassers have a fuel pump relay you can jump to test. Maybe see if theres a way to run the fuel pump while being safely under the vehicle to see if youre leaking fuel.
there should also be a way to test pressure on injectors. If they were all significantly lower than spec, that would be a good indicator.
im also assuming you have a return line, which is probably less pressure. you could have a leak here which would be harder to test for
Ive hung out underneath the vehicle while it's running. both warm and cold while revving and nothing seems to be leaking or seeping at all.
So this fluid i have, is there a way to figure out exactly what it is? Like if its actually diesel is there a way to test it somehow short of sending it to a lab? Am unable to find anything on the internet.
There are test strips for coolant, brake fluid, probably fuel, but youd probably need a significant amt and theyrw designed to tell you the condition of the fluid not what fluid it is but its one of the following:
trans fluid- atf or manual?
engine oil
diesel
brake fluid
maybe gear oil from a diff?
So you could buy test strips for these and see if they tell you anything.
Id probably figure out a way to test fuel pressure because to me that would be the worst and probably most dangerous leak. Maybe put a gauge in somewhere you could monitor it.
My next concern would be losing brake fluid. You can check master fluid level. If youre losing brake fluid, youre brakes would be terrible and youd get a dash light. You could gravity bleed the rear brakes and see bubbles if theyre leaking.
Engine oil youd see it leaking somewhere. Ive got cars that have oil spraying back from the radiator fan and it can splash pretty far back. So dont eliminate it.
Trans or gear oil should be leaving a wet spot wherever its leaking from. These oils have a burnt smell but in small amounts might not be noticeable.
This is just some shade tree thinking...tryna help you out with what little I know.
Brake and fuel lines usually corrode at bends and connections where water can sit on them.
Last edited by swampedout; 12-21-2020 at 07:00 PM.
Appreciate the info thus far, here are some pics. Ill clean it up again, and check consistently to see where stuff starts to leak. Located right behind the transfer case.
Check all fluid levels and monitor closely before and after driving. Diesel and transmission fluid as you stated smell but I've been fooled before with gear oil, or my nose has a miss fire.
You didn't mention if auto or manual, As it could be hydraulics for manual clutch or auto line to or from radiator.
Any leak under rig when driving has a tendency to cover everything.
My money is on a transfer case leak. What's the back of the case look like? Pics would help.
With a rear transfer case shaft seal leak, that's what my underside looked like. For things on shafts, you can look at the slinging pattern to judge the source.
Well i took another look, and something must have happened to leak even more. Previously it just looked greasy with a bit of sand stuck to it, however today i came across some actual wet spots, that 100% smells like some sort of gear oil. This is a manual transmission as well so i believe they use gear oil as well as the tcase.
What is weird, is that one of the flanges of the driveshaft has traces of gear oil, and it looks like it has been slung around by the driveshaft to cover everything, however the seal between the driveshaft and the t-case looks clean. The only thing that looks greasier than the rest is that cable entering into the top of the little actuator looking thing but i'm unable to find any drawings online of what it is, the actuator housing maybe? Its
Last edited by HiluxSurfGuy; 12-24-2020 at 03:15 PM.
So it looked like it was the seal between the driveshaft and the flange, so i took it apart and this is what i was left with.
I'm unsure if it was actually this one,for the amount of oil that is spread out it doesn't look like much is inside the flange. There IS a tiny bit of gear oil in there, specifically between the nut and the shaft, but i would envision it being more if that was the leak. Maybe the amount of force that is exerted quickly expels it from the flange? Or maybe its leftover oil from the last time the driveshaft was taken off?
I think your inner oil seal is bad, but the outer seal is good. If the outer seal were bad, you'd see oil closer to the transfer case. If the inner seal is bad, it could make it through the splines that are behind that nut and washer, and then sling out at that location. It should have been bone dry where that nut is in your picture. (30mm socket for that nut)
Also, grab that flange and see if it moves. Frequently, when bearings start to develop play in them, the runout will cause adjacent seals to fail.
See my other post about the list of seals I purchased to repair mine. If you need to go super cheap, that inner seal is <$10, and you could get buy with just that and the paper gasket to that last transfer case casting. But me? After investing the labor of taking it apart (it's easy), I'd replace both seals and the bearing if you feel any play at all. No special tools required.
After sleeping on it, I'm not sure my thoughts about the inner seal are right, but still, I'd start with replacing those two rear seals, and maybe the bearing. Here's the thread where I talked about doing mine -- it includes the parts lists and links to helpful videos: https://www.yotatech.com/forums/f116...cement-312363/
There is no 'inner seal' that exists to prevent oil leakage to the outside of the transfer case; only the seal at the output flange does that.
Leakage might occur at the output flange nut if it becomes loose. The sealing there is only by virtue of the usually tight fitting parts, and a good degreasing and application of
FIPG or similar sealer is not out of place on the splines and under the nut and washer, on assembly.
That 'inner seal' only acts to insure the function and integrity of the oil pump that is part of the output shaft and the output end of the case housing itself.
There is no 'inner seal' that exists to prevent oil leakage to the outside of the transfer case; only the seal at the output flange does that.
Leakage might occur at the output flange nut if it becomes loose. The sealing there is only by virtue of the usually tight fitting parts, and a good degreasing and application of
FIPG or similar sealer is not out of place on the splines and under the nut and washer, on assembly.
That 'inner seal' only acts to insure the function and integrity of the oil pump that is part of the output shaft and the output end of the case itself.
Yes, as I replied earlier, I misspoke on the inner seal.
So i'm going to reckon in order to replace the bearing i have to open up more than just taking that nut and the flange off? I'm not a huge fan of fixing things that aren't broken, and taking the driveshaft and flange off isn't that big of a job. So i think my next plan of attack is these 2 seals right here. The one circled in blue is the problem one, and i'm gonna do the red one while im at it.
Maybe I've been off base here.
Your diagram appears to show a VF (chain drive) case) Not the RF type case that I have been jibbering about.
On your VF type case there is only one seal at the rear, and that is the seal circled in red. Pretty sure that the blue circled part is just the heavy washer that lays behind the flange retaining nut.
I don't know whether the output bearing on this chain drive case can be easily changed, or not.
The FSM should be consulted. The RF1A gear drive cases I am familiar with are a different animal than what you appear to have.
Me too. I've been talking about the gear-drive case (came with 22RE non-turbo and MT5), not the chain drive case. I've no experience with the chain drive case.
12-20-2020, 06:44 PM
