a518 atf+4 or other?

[IrishChamp]

I'm getting ready to change my trans fluid, I had the trans rebuild a while back, 10-15k miles ago maybe and I believe I was supposed to change the fluid at 5k or 10k after rebuild.
anyway, I'm 95% sure the builder used a generic atf+4, should I use mopar atf+4, type F, Hydrolic fluid or other for the change?
I"m also putting a Derale 14210 Pan, Derale filter extension and a trans temp gauge.
what prompted me to get off my ass and do this is: yesterday I got on the go pedal, it shifted from 2nd to 3rd and then immediately into OD, premature od shifts are not unusual (another thing on my list) but this one was immediate, boost spiked to almost 40, I usually don't see much over 32-35 and it felt like the trans slipped, I immediately let off. I've never had any problems with the trans besides 2-3 shift being much firmer than the others. it was hot out, 100 approx. my trans cooler fan has been running every time I drive lately.

Any insight and advice would be greatly appreciated. I do most of the work on my truck, every time is a new adventure though, I am NOT an automotive expert

[PToombs]

Any brand of ATF type 4 is fine, some guys use hydraulic oil for a full or partial fill.

[IrishChamp]

does the hydraulic oil have any known negatives. it provides firmer shifts correct? I'd really like firmer shifts on the 1-2 AND 3-OD shifts.
any particular type of hydraulic fluid?

Any brand of ATF type 4 is fine, some guys use hydraulic oil for a full or partial fill.

[PToombs]

Not that I know of, maybe slower shifts in cold weather because the oil is thicker. JD Hygard is a known favorite.
Someplace on here is a thread about it.

[dazedandconfused]

Hydro oil helps with heat and firms up trans some since it is a little thicker. I'm running it in mine and its helped it out.

[IrishChamp]

I appreciate the info guys. my transmission is build up with extra clutches a really tight converter, planetary upgrades and a shift kit. I've never been happy with how it shifts though. the 2-3 shift is the best but its almost too hard. I'd rather them all be this hard though.

[lz69]

From doing a little reading after some transmission work, atf 4+ has very tight specification so there next to no difference from a generic bottle from Walmart and stuff from the dealership. As example to meet specification it has to be from one of three refineries and use an additive package from a specific manufacturer.

[oldestof11]

I use Travellers Hyrdo trans oil in my junk. 4qts ATF and the rest the hydro oil. It really tightened up my loose converter. Tight enough I went from 17-18mpg to a consistent 19.5-20.5 mpg. Nothing changed between the 2 besides a rear main seal replacement. $40 at Tractor Supply company.

[IrishChamp]

That's good to know. I've always wanted to think that but people always swear by one brand or another.

From doing a little reading after some transmission work, atf 4+ has very tight specification so there next to no difference from a generic bottle from Walmart and stuff from the dealership. As example to meet specification it has to be from one of three refineries and use an additive package from a specific manufacturer.

[IrishChamp]

Man that's some nice MPG. I can't seem to get more than 12 unloaded in my day to day and 12-16 on trips pulling a little 12ft trailer.
I have a very tight converter, hopefully hydraulic fluid won't tighten it up too much.
The next thing to address as far as fuel economy goes is my injectors, everything else has been addressed I think.

I use Travellers Hyrdo trans oil in my junk. 4qts ATF and the rest the hydro oil. It really tightened up my loose converter. Tight enough I went from 17-18mpg to a consistent 19.5-20.5 mpg. Nothing changed between the 2 besides a rear main seal replacement. $40 at Tractor Supply company.

[oldestof11]

I didn't see that tight converter. Yes it will tighten it up more. You might not want that.

[IrishChamp]

Maybe I'll give it a try next week after when I won't be needing my truck for work.
thanks

I didn't see that tight converter. Yes it will tighten it up more. You might not want that.

[IrishChamp]

anyone have any first hand experience with a tight converter and hydraulic oil?

[dazedandconfused]

BC847 (David) does.

[cmann250]

I have an off-the-shelf Suncoast converter and I use hydraulic oil in my transmission. I originally used regular ATF because that's what I had on hand and I changed to hydraulic oil when I put on a deep pan. I'm assuming that an off-the-shelf Spec Rite is more or less the same as an off-the-shelf Suncoast converter. After the switch, the seat of the pants dyno says it pulls harder.

All I can say is it works for me. There's still no mistaking it for a lock-up trans though.