View Full Version : 80 series t-case running hot?

11-16-2009, 01:30 PM
My dad's 80 t-case was running hot this past Friday driving up from Denver to Vail with my mom and sister (stock 80 with turbo and 285s). He says it was hotter than the tranny, and too hot to leave his hand on. He's just wondering if that's normal or if there might be something going on. I'm not sure when the last time the t-case was serviced on that vehicle, the truck has about 130,000 miles on it and I think the t-case fluid has been changed within the last 20-30,000 miles.

The reason he was stopping to feel the t-case is because he was getting a burning smell, and the drain plug was loose and had been leaking and I think some oil was getting slung onto the exhaust or something...t-case was not low on fluid though.

11-16-2009, 01:56 PM

I've never touched my t-case/center diff after a long drive but judging by the heat generated by the exhaust etc. that makes the PS floor very hot I wouldn't be surprised that the center diff case would be hot...

Only comparison I can offer is after a 10 minute drive on the highway my hubs are cool to the touch but my diffs are hot - not burning skin hot but hot enough to make it uncomfortable to keep your hand on there for very long.

Out of curiosity I checked the interweb but nothing conclusive...Did find that Amsoil gear lube (http://www.amsoil.com/StoreFront/fgr.aspx) (some claim it is one of the best makes right?) has viscosity indexes at 40C and 100C which is 104F and 212F respectively. That is pretty hot :)

11-22-2009, 11:01 AM
I don't know specifically about the later FJ's (I had a 40) but I recently found my 1st gen 4runner was not disengaging the front hubs so they were always spinning the drive shaft and gears back at the T-case. Once I fixed the hub issue the t-case heat went way down. Also the new Synthetics do indeed make a lot of difference. If you're an old patroleum die hard then disregard, but for the rest of us, considering we change our gear oils every generation, running the absolute best you can find only makes sense. A good guage is to regularly grab the shift lever down close to the boot so you'll get to know what is normal heat and what is not. Amsoil is probably good. I lean toward Mobil 1 gear oil. I use Rotella T Synthetic for the engine.

11-23-2009, 10:37 AM
The 80 series is a full-time 4wd, so the t-case is designed to always be running. It has a viscous coupling in it to proportion power from front/rear. I believe my dad is running synthetic in it, but I don't think that would really make a difference either way.

By the way, not all synthetics are truly synthetic. There are a lot of synthetic blends out there which say "synthetic" on them. You have to research it a little more closely. Mobil 1 and a couple others are the only ones that have a truly full synthetic product in their line.

11-23-2009, 11:14 AM
It's completely related to the turbo- only way to solve it is remove all of the turbo components immediately and put them in a box, including the A-pillar gauge pod, those things are just heat monsters. The whole system is a big liability, let me know when you get it out and I'll come down to pick it all up and see that it gets properly disposed of..

11-23-2009, 04:29 PM
Tim, I don't think a turbo is compatible with a snackster. Or a hotdogger for that matter, so you're out of luck. Sorry :(

11-23-2009, 07:51 PM
Tim, I don't think a turbo is compatible with a snackster. Or a hotdogger for that matter, so you're out of luck. Sorry :(

You are definitely correct. I will dispose of the parts properly as Tim can not.

11-24-2009, 10:24 AM
Sorry Corbet - I don't think Porter would appreciate being plastered against the rear window when your foot accidently goes into "heavy" mode - so for Porter's sake I can't allow that to happen...:D

I'm thinking the solution is that I need to drive it around for a few months, say a year or two, to try and recreate the smell and do some more diagnostic work...:D