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Auto transmission go boom.

Posted: Thu Jan 05, 2017 1:42 pm
by Growlerbearnz
It wasn't completely unexpected: hauling 3600kg up a 10% grade at 20psi of boost is a big ask of a slightly unhappy transmission with a quarter-million kilometers under its belt.
By the time we reached the top of the hill the ATF overheat light was on (first time ever on that hill), the 1st-2nd shift was a bone-jarring whack in the back, and the 2nd-3rd shift was one big long mushy orgy of engine revs. The ATF light went out quickly, but the other problems remain.

The upside is now I have an excuse to rebuild the transmission with stronger clutch packs, and lower the torque converter's stall speed to match the engine's torque. :-)

Auto transmission go boom.

Posted: Thu Jan 05, 2017 2:07 pm
by Morgonzo
Hooray for looking on the bright side GB! :-) I've been thinking lately about trying to get a second Man Trans (not a trans man..) and trying different gear ratios (taller 1st and 2nd would be nice) but i'm not itching to fry my current one to get a core. What do you think caused the failure? was it the weight or just it's time?

Auto transmission go boom.

Posted: Thu Jan 05, 2017 7:55 pm
by Growlerbearnz
I think the root cause of the failure is that it was neglected before I got it. The ATF was very dark and murky, the 1st-2nd shift always a touch harsh, 2nd-3rd shift a bit sloppy. Changing the ATF helped a lot, but I think the damage was already done- every time it shifted from 2nd to 3rd it slipped a bit more, though the change was so gradual I thought I was imagining it.

Towing, plus the extra power from the new turbo and intercooler, has certainly accelerated the process. The transmission should be plenty strong enough- the same item was fitted to the 4.2l diesel landcruiser- but once it starts to fail it's all downhill from there.

3600kg isn't outrageous. Towing a trailer full of dirt (1200kg) with 4 people in the van comes to about the same weight.

Auto transmission go boom.

Posted: Fri Jan 06, 2017 3:16 am
by Growlerbearnz
Here's a photo ;-)

IMG_0071.JPG
IMG_0071.JPG (503.28 KiB) Viewed 2988 times

Auto transmission go boom.

Posted: Fri Jan 06, 2017 9:38 am
by Morgonzo
Damn! :o Talk about 20 pounds of crap in a 5 pound bag! :-) I've recently done the trans fluid in both Big "D" and the '90 Camry and both were the color of choco milk...but that's after putting Seafoam Trans Tune in and running it hard. They both shift MUCH better afterwards.
How much is a new trans or rebuild gonna cost? Can you still drive it reliably until you're ready to do the work?

Auto transmission go boom.

Posted: Fri Jan 06, 2017 1:09 pm
by Growlerbearnz
They reckon around NZ$3500 (US$2500) all up, including removal and reinstallation. Normally I'd do the removal and reinstallation myself, but if it blows up again I don't want them to say it was an installation fault. That and my workshop's ceiling is low enough that I can't lift the van high enough to get the transmission out- I'd have to work outside on the driveway, and I'm now officially too old for that shit.

It still drives ok(ish) and will probably last until next week when they can start working on it, but I'll be treating it gently and not towing anything too silly until then.