833 OD transmission lube and overdrive ratio question?

[71340RT]

I picked up a rebuilt 833 overdrive 4 speed at Mopars at Indy this past weekend and wondered what transmission lube works best in them? I'm sure mopar had automatic transmission fluid in it from the factory but wondered if I could use synthetic gear lube with no prblems? Anybody had any issue please let me know before I pull my 4 speed and drop the overdrive in. It's marked PP 833 and read 5-21-82 on the side case. It has both mounts on the tail shaft and I also wonder how much this is going to drop my RPM's in 4th gear? Thanks for the help.
Jeff

[Chryco Psycho]

the final drive ratio in od is .71 so if you have 3.55 gears multiply that by .71 = 2.52 so lots
 the factory lube is 80/90 gear oil Not auto trans fluid , ATF was recommended for extreme cold climate like where I live
 there are 2 synthetic fluids I can recommend , REDLINE has a manual trans lube with friction modifiers to allow the syncros to work properly , Also Mopar has a similar synthetic manual trans lube

[70challengerrt]

I used the red line and my syncros would grab. 80-90 worked best for me. My od tranny with 3.54 dana rear end and I run about 2200-2500 at 65 mph. What I like the best is the low 1st gear when I calculated it out its close to having 4.11s in the rear end. You do have to bend one of your linkage rod for the 3rd-4th gear.

[71340RT]

I ordered redline 75W90 synthetic gear lube today. Now I just need to get the bearing retainer turned down to 4.80 and make time to pull my 4 speed out and put the overdrive 4 speed in. I can't wait to take it out on the open road and see what a difference the transmission will make as the 340 just felt like it needed another gear or overdrive.
Jeff

[Chryco Psycho]

Most but no all of the poeple I have done conversions for love it

[70challengerrt]

When I read my post I phrased it wrong the red line synthetic did not allow the syncros to work properly and the gears would grind. Straight 80-90 worked much better. Sorry for the misinformation.

[madness]

my 4 spd felt the same way it has alot to do with rear gearing 3.23 here i put th 5 speed in realy like it u have to make a few ajustments to make it work my rear gears are sloppy thinking 3.55 s