Transmission fluid service interval

[athens7]

The owner's manual says to replace the transmission fluid every 150,000 miles. The Boss 302 supplement makes no mention of a different interval. What interval would the forum suggest for a DD that goes to the track 7-8 times per year? Does shift quality degrade as the fluid ages, or does the fluid work to spec until it fails?

 

[06mach1]

I change it once a year. I use Redline MTL. It is cheap preventive maintenance if you are dong it yourself.

 

[F.D. Sako]

I change it annually as well. I have never noticed a change in shifting due to fluid degradation (I thought I was once, but turned out to be clutch failure). I've been using BG synchro shift II with good results as a year round weekend car with 5-7 track weekends in the summer.

 

[steveespo]

Depends on how hard you push on track but 7 days plus DD should be OK for annual change. If you do 7 weekends (14 days) then you should chage every 7 track days. Street driving does nothing to the fluid, temps rarely exceed 150 degrees, track driving at high speed and high rpm downshifting sees the temps skyrocket to 280+ degrees, this kills the fluid and puts many more contaminents in the fluid from synchro wear. I run a trans cooler setup and change every 8 hours on track.
Steve

 

[athens7]

Thanks for the input.

 

[Black Boss]

Boss 302S recommendation is every 4 hours for both Trans & Diff Fluids. I agree with Steve, sustained hard driving raises both Diff and Trans temps. I am changing both fluids at 4-8 hour intervals based on ambient temps and session duration (30 minute sessions drive noticeably higher temps than 20 minutes).