Recommended fluid for T5 transmission???

[caionneach]

My T5 tranny has, it appears, 30W oil in it.

My manuals each call for Dexron II. If I recall correctly, a technical bulletin said 30W could be added to the T5, but I don't remember why.

What should I use? I purchased Coastal ATF that is Dexron 2 & 3 compatible, and with the shifter out, will fill through the shifter housing.

[joe]

Originally the t5 designers called for 30w motor oil and then the fog/clouds passed (or they started doing piss tests there) and went to AFT Dexron III . Run the Dex and live happy.

[caionneach]

What about Royal Purple and other synthetics?

There's an interesting discussion about T5's in CJs over at http://www.jeepsunlimited.com/forums/showthread.php?t=417376, and some of the respondents note the lack of needle bearings in the Jeep/Non-World Class T5, and thus it should use gear oil.

But I have Dexron II/III, so tonight that's what it will be. However, if soemthing different will make it shift better, then I will use it.

[Ristow]

automatic transmissions use several bushings and they last a long time.

[joe]

What about Royal Purple and other synthetics?

.
I like syn lube and run redline syn atf in auto and manual trannies that call for atf as well as in chain drive transfercases that use atf . Royal P has a good rep but I have no expierience with it.

[jpcoutts]

I've seen quite a bit of discussion about what to use in the T5 and after doing some research I decided to use gear lube (85w90 I think). It works fine and has a good feel but I don't put many miles on my CJ or pull any heavy loads with it. I'm sure the original spec for ATF had something to do with fuel consumption.

My .02

[shackwrrr]

if they have paper style blocker rings(WC) they use atf. And if they have bronze blocker rings (NWC) they take gear oil. The jeep one is a NWC so it takes gear oil 70wt to be exact

[twmattox]

I have researched the snot out of this...

Technically, AMC recommended against ATF because of issues with first gear... The ultimately recommended an AMC special fluid. In short, today, Chrysler recommends gear oil. However, make sure to use synthetic (for easier cold shifts) and one that is safe for "yellow metal".

Realistically, I have run nearly everything in a T-5 (ATF, motor oil, standard gear oil, synthetic gear oil, and combinations of all the above). I have also driven the absolute crud out of them (over 200k on a couple transmissions and 150k on the other before it grenaded when the fluid ran dry...). I think the most important thing is to make sure you are not using too big a motor (torque limits on the transmission), that you keep it lubricated, and that you are not trying monsterous things with a mild transmission.

[joe]

I've seen quite a bit of discussion about what to use in the T5 and after doing some research I decided to use gear lube (85w90 I think). It works fine and has a good feel but I don't put many miles on my CJ or pull any heavy loads with it.
My .02
Are you serious??? When I drained my first t5(82cj8) and saw the cherry juice I thought PO was a fool and installed 85w90 gear lube. thank goodness I wasn't in MN or such place that was really cold but at 45*F I couldn't even get the trans to shift out of neutral. you're really running gear lube in a t5?

[jpcoutts]

Yeah Joe I just went out and looked at the bottle and it's 80w90. I've had no trouble shifting. Isn't there also some disagreement about what to run in the D300 CJ t-case? I run the 80w90 in that as well.

[joe]

Yeah Joe I just went out and looked at the bottle and it's 80w90. I've had no trouble shifting. Isn't there also some disagreement about what to run in the D300 CJ t-case? I run the 80w90 in that as well.
I run gear lube in the D300 also.

[ecardona10]

I currently own and daily drive a CJ7, and my T-5 gets only synchromesh (comes in a yellow bottle). After allot of reaserch on Jeeps Unlimited, Jeep forum, and CJ Offroad, this was the consensus. It is safest for "yellow metals" in our tranny's as well as easier to shift in cold weather than 85-90.
Just my 2c.

[CROCKETTBOONE]

There was a recall on the T-5's in the 1982 models. It seems the gear oil was so thick that first gear hub could not get proper lube. The fix was to put ATF in the transmission and not gear oil or any other oil. I had mine lock up in first gear at 65MPH. First gear was welded to the shaft and syncro. After lots of fixing I got it going again.

If you are running a world class T-5 then there is no worries. The hubs are flutes to increase lubrication.

For more information go to 5speeds.com

[caionneach]

Gear lube is what should be run, but it really should be a synthetic and a lighter weight. Those in really cold climes especially should use the 75w-90 synthetic.

Care should also be made to choose a lube that doesn't eat the bronze synchros in these boxes. GL3 fluids currently recommended by Chrysler won't eat the bronze synchronizers in these transmissions.

So for now, my box will run ATF. Then I'll switch to Redline or Valvoline synthetic 75w-90.