Oily substance all over back tailgate

[garydan]

I took my truck for an unusually long highway drive of about 85 miles round trip. It's typically a weekend warrior around town.

When I got back I noticed the rear tailgate was covered with an oily substance. I have a feeling that it may have come out of the exhaust and the backdraft splashed it on the tailgate.

But... I also had some droplets on the windshield. I don't get it. What was on the windshield didn't look like oil, more like coolant.

The truck does burn oil, maybe its just unburnt oil passing through the exhaust. I guess its getting closer to the 4BT swap

 

[super k]

Prolly oil in the exhaust but could be a leak. Did you check upunder for leaks?
BTW,I lived in your area in the late '70s. Cool area,at least back then. I first stayed at the marina in Rio,then moved up Indian River Drive to Walton. I worked for Lydia Yachts in Jensen Beach. We used to wheel The Savannas big time. I had a blue '69 W200 Power Wagon with 14.50/37 Armstrongs. Good luck with your truck and don't eat too many snooks! LOL

 

[meanboyjr]

I took my truck for an unusually long highway drive of about 85 miles round trip. It's typically a weekend warrior around town.

When I got back I noticed the rear tailgate was covered with an oily substance. I have a feeling that it may have come out of the exhaust and the backdraft splashed it on the tailgate.

But... I also had some droplets on the windshield. I don't get it. What was on the windshield didn't look like oil, more like coolant.

The truck does burn oil, maybe its just unburnt oil passing through the exhaust. I guess its getting closer to the 4BT swap

The same thing happened to me when I first got my Blazer. Turned out it was tranny fluid from a leaky pan gasket. It covered the tailgate and window with a fine, oily mist after a nice long drive at freeway speeds.

Where does your exhaust exit? The back or side of the truck?

 

[garydan]

The same thing happened to me when I first got my Blazer. Turned out it was tranny fluid from a leaky pan gasket. It covered the tailgate and window with a fine, oily mist after a nice long drive at freeway speeds.

Where does your exhaust exit? The back or side of the truck?

Interesting... It exits to the side. I didn't notice anything under the hood though. I have yet to crawl under the truck to be honest.

 

[garydan]

Prolly oil in the exhaust but could be a leak. Did you check upunder for leaks?
BTW,I lived in your area in the late '70s. Cool area,at least back then. I first stayed at the marina in Rio,then moved up Indian River Drive to Walton. I worked for Lydia Yachts in Jensen Beach. We used to wheel The Savannas big time. I had a blue '69 W200 Power Wagon with 14.50/37 Armstrongs. Good luck with your truck and don't eat too many snooks! LOL

Port St Lucie sucks. I grew up in the Jupiter area, much nicer down there. But like many people who decided not to foreclose...I'm stuck underwater in a house worth half what I bought it for.

 

[ZJumper]

Check the rear driveshaft seal at the slip yoke.

I had the same symptoms as you describe and the seal was the issue.

 

[79rustyk10]

I had the same thing happen when the oil pan gasket went out in my ford.

I would guess an oil leak somewhere.

 

[Hogback Fabrication]

Pretty typical for an oil leak under the truck to cover the rear window as mentioned

 

[meanboyjr]

Judging from the responses, it seems like there might be a leak under the truck, be it oil or tranny fluid.

I asked about the tailpipe placement because I didn't think unburned oil in the exhaust would cover the rear window with a side exit tailpipe. Stranger things have happened, though.

Hope you find what caused it.

 

[Blue85]

When it happened to me, it was the rear differential leaking from the pinion seal.

 

[Swanson52]

Had the same thing, but it was both a rear main and transfer case seal.

 

[diesel4me]

My older brothers 2002 GMC 4x4 had oil droplets sprayed on his tailgate,and he discovered the pinion seal on the rear diff was shot....fixed it,and about a year later he saw more droplets all over the tailgate after a 80 mile ride to my house,and he found it was ATF coming from a HOLE in the transfer case!...evidently its not uncommon for the oil pump in the transfer case to wear a hole in the housing on the tailshaft housing where it rides..Kennedy Diesel sells a kit for about 50 bucks to repair that,but he opted to buy a new tailshaft housing at a dealer for 250 bucks rather than "patch" it with the kit and some cold weld compound,though it probably would have worked fine...