Bought the 4R used, when to change the tranny fluid?

[Shawn5800]

Hey guys, i have been buying used vehicles all my life. Everytime i buy one i change all the fluids out with new, except the tranny fluid. Mainly because im scared as to when it was changed previously.

I never know if it was changed regularly or never changed at all. Im scared of draining it and adding new because of the viscosity changes on the seals..\\

So whats good advice for someone with no record of changes? My truck seems to shift fine for the most part. Just the normal hard shift into 2nd at first start then goes away.

 

[Lineman]

Good advice for no record of changes.. Change them all.. You can tell if your tranny has ever been changed though. Use the visual = clean, and taste it = not burnt.

 

[trailmix]

I always change the tranny fluid when i first buy a vehicle regardless of its past. Ive always read that the all the new detergents in the new fluid can kill a old tranny but i have never had that happen and in every case the trans always shifts better then before i changed it. Just did it on the 96 i bought a few weeks ago and it helped it quite a bit. I do like to add a bottle of the lucas stop slip when i change it though just to give it a little help.

 

[Maritimer]

I changed mine without thinking of this.

It slips a bit these days, and I'm hoping another change out after having the other stuff brighten things up in there for a year will do the final trick.

 

[Shawn5800]

Thanks for the advice guys, Upon visual inspection my tranny fluid on the dipstick seems to be a very dark red. Almost like a bitter red wine look. Does that sound normal? It does not smell burnt...I have yet to taste it lol.

Also, why is the tranny dipstick such a PITA to put back in on these trucks!!

 

[RC57]

Also, why is the tranny dipstick such a PITA to put back in on these trucks!!

I bought my T4R used and the dipstick had one kink and two twists in it, not including the bend at the tip. The two twists appeared to be factory. I straightened the kink and twists. That helped some.

It also helps to start it with the bend aligned a certain direction, I forget which way. I put a sharpie mark on the handle so I can start it the preferred orientation each time.

 

[Baja Runner]

That AT fluid sounds normal to me. I flushed it when I bought my new truck. Also check sparkplugs...mine were original with 150k on them

 

[Nunyabiz]

Thanks for the advice guys, Upon visual inspection my tranny fluid on the dipstick seems to be a very dark red. Almost like a bitter red wine look. Does that sound normal? It does not smell burnt...I have yet to taste it lol.

Also, why is the tranny dipstick such a PITA to put back in on these trucks!!

Good it doesn't smell burnt, but it sounds like it might have quite a few miles on it.
Personally I would change it and I don't mean just draining a few qts out and putting 3-4 back in thats just about worthless.
I would drop the pan and look at it, check the "screen" (we do not have an actual filter) and check the magnets in the bottom of pan and see what they have collected.
Button everything back up and drain out a qt at a time and replace a qt through the trans cooler/radiator hose until you start seeing cleaner fluid coming out.
I much prefer synthetic ATF personally, last a bit longer between drains and keeps the trans running a bit cooler but to each his own.