Did I cook my tranny?

ANYTHING RELATED TO MANUAL OR AUTO TRANSMISSIONS GOES HERE.
Post Reply
User avatar

Topic author
Herbie
ASV Supporter
ASV Supporter
Posts: 674
Joined: Tue Aug 04, 2009 10:45 am
Location: San Diego, CA
Has thanked: 12 times
Been thanked: 4 times
Contact:

Did I cook my tranny?

Post by Herbie »

Right off, let me say I have no symptoms, but I have concerns because I saw some very high transmission temps this past weekend.

Now first off, I know I should have a tranny cooler. I actually own one - it's sitting in a box from when I ordered it a couple of months back. No, it's not installed, because I got to focusing on wife-priority items. Yes, I'm aware it doesn't actually do me any good sitting in a box. Yes, I will install it soon.

All of that out of the way, here's my question: I'm using the ScangaugeII to read the OEM Tranny Temp sensor. I am concerned that I mis-calibrated my brain about what "proper" tranny temperatures should be, and as a result I let the temps get too high this weekend.

Without an aux cooler, I normally see ~185 under mild conditions (A/C off, not climbing, etc.), once everything is warmed up. I have seen as high as 210 or so on a hot day, with A/C running. I convinced myself this was "normal".

While driving up a switchback road up the mountains this weekend I saw temps climbing up past 210. I was starting to get a little concerned, but was more worried about the fading light, etc. and I just kept going. Getting behind some traffic I got to a point where I was at a bad speed for my big-tires and tall gears so the transmission was hunting a lot trying to pick a gear. I got to watching traffic, the road, and everything else and it wasn't until near the top of the hill that I saw the tranny temp was reading over 240!!

I cooled it off then (last bit of easy/downhill driving then into camp and shut it down), but that number scared me. Reading others reports here and it seems like even my ~185-210 might be on the high side and I'm REALLY worried that the climbing temps and short time ~230-240 might have done damage.

Should I do anything other than installing the cooler?
Should I change my fluid, then wait to see if anything happens?
Or am I well and truly farked?
"My minivan is cooler than your bro-truck"
2003 Astro AWD Astrolander/ZMB - GTRV Top Transplant, 4" OLV Lift, NP233 T-case, evolving interior
1995 Safari GTRV Organ donor - gutted and gone.
Image
User avatar

Smiliesafari
ASV Supporter
ASV Supporter
Posts: 2667
Joined: Sat Dec 02, 2006 12:34 pm
Location: Orlando, FL

Re: Did I cook my tranny?

Post by Smiliesafari »

If it's still working then it's probably fine. Over heating once probably didn't hurt it. If you have ever over heated the engine then you over heated the transmission also. I've done that twice to my Safari and at 263,000 miles it still works fine.
1996 Safari SLX Hotair balloon transport vehicle

bluesea
I am merely driving my van
I am merely driving my van
Posts: 14
Joined: Thu Dec 20, 2012 11:27 am
Location: Switzerland

Re: Did I cook my tranny?

Post by bluesea »

Pull out the messurement stick and smell on the fluid. If it smells burned change it and dont forget the filter.
__________________________________
1995 Chevrolet Astro AWD 2" lift
camper/expedition vehicle conversion
2nd battery, 230W solarpower on roof
compressor fridge
Eberspaecher air heather

LiftedAWDAstro
I have my van tatooed on my cheeks
Posts: 4379
Joined: Sat Sep 09, 2006 3:35 pm
Location: New Haven, NY

Re: Did I cook my tranny?

Post by LiftedAWDAstro »

Yeah, you are fine. Change the fluid and filter and flush to synthetic and install that cooler! I have seen times with the SPB where I was running at 250* + while towing or climbing some hairy spots when wheeling. I just let it cool down as soon as I could and kept the Amsoil synthetic fresh.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy
User avatar

Wiley
ASV Supporter
ASV Supporter
Posts: 313
Joined: Mon Nov 22, 2010 3:02 pm
Location: Socal

Re: Did I cook my tranny?

Post by Wiley »

I had some problems on a beach down south and got my temps way up....it was just a short time, but I have had zero problems since then, I agree with the experts, I just wanted to sound smart. I would change the fluid just to be safe.
2guys1truck.com: 2004 AWD Chevy Astro from California to Colombia!
want to follow along, or think our paths may cross, Facebook kjswiley
User avatar

Stroverlander
I sleep in my van
Posts: 308
Joined: Fri Dec 16, 2011 4:18 pm

Re: Did I cook my tranny?

Post by Stroverlander »

If/when changing the fluid, go with a Dexron IV fluid - much better life and friction stability, maintains viscosity, less foaming and better shift performance. When I'm finished with this last box of Amsoil, I'm going to try Castrol (syn blend) or Valvoline (full syn) Dexron VI.
2004 Astro LT AWD Stroverlander
Post Reply