8 Speed transmission fluid change - only 4.5 quarts?

[Rebel.Matt]

Reaching out to the forum for some help and guidance. I just changed my transmission fluid on my JT Rubicon with 63k miles on it. Process was fairly easy and I went very slow and methodically since I've never done this before. For first fill, I was only able to get about 3.5 quarts of fluid before it started seeping out. Then I did the whole process of going through the gears and was able to get some more fluid in, but total 4.5 quarts. Everywhere I read says 5-6 quarts. Did I do something wrong? My jeep was fairly level in my garage, does the rear end need to be higher?

Looking for a lifeline, I'm planning on doing some driving tomorrow and I don't want to be left on the side of the road.

Sponsored

 

[Maximus Gladius]

Reaching out to the forum for some help and guidance. I just changed my transmission fluid on my JT Rubicon with 63k miles on it. Process was fairly easy and I went very slow and methodically since I've never done this before. For first fill, I was only able to get about 3.5 quarts of fluid before it started seeping out. Then I did the whole process of going through the gears and was able to get some more fluid in, but total 4.5 quarts. Everywhere I read says 5-6 quarts. Did I do something wrong? My jeep was fairly level in my garage, does the rear end need to be higher?

Looking for a lifeline, I'm planning on doing some driving tomorrow and I don't want to be left on the side of the road.

Level frame. 3.5 is right for initial fill till fluid dribbles out, engine is off. Plug the fill hole and start engine. We don’t wait here for temp window, start engine and immediately get underneath, pull plug and fill, should take another 2 - 2.5 quarts. If we decide to wait… pump will suck air and air doesn’t lubricate.

What temperature did you decide to run the gears and settle on as “full”?

 

[Rebel.Matt]

I got it up to 115 degrees or so, went into neutral, revers, first and second, then filled a little more, then went for a quick spin around the neighborhood, turned the jeep off, then checked it again. Total fluid was about 4.5 quarts. What I'll do here in a bit is get it up to temp again and then fill it while still running, that might be what I'm missing.

Also, I filled it on a flat surface buy by jeep does sag a little bit, should I jack it up in the back and see if I can squeeze more in there?

Thank you for your suggestions and feedback.

 

[Maximus Gladius]

I got it up to 115 degrees or so, went into neutral, revers, first and second, then filled a little more, then went for a quick spin around the neighborhood, turned the jeep off, then checked it again. Total fluid was about 4.5 quarts. What I'll do here in a bit is get it up to temp again and then fill it while still running, that might be what I'm missing.

Also, I filled it on a flat surface buy by jeep does sag a little bit, should I jack it up in the back and see if I can squeeze more in there?

Thank you for your suggestions and feedback.

You’ll want to stay frame level. If you’d like more in there, run the gears at 90F and finish the levels by 92-93. The hotter you wait, the less that goes in. Don’t jack the back end up and not be level.

 

[Maximus Gladius]

Ya,…settle on the cool side of the temp window and finish running the gears then. Go drive it, watch the temp gauge. There’s no instructions from ZF to raise the back end if “you feel it needs more”, so don’t do that. It wants what it wants with frame level and cool side of temp window.

 

[DylanM]

This is the reason it's a good idea to measure the amount of fluid you drained out when performing your fluid change. Knowing how much came out will give you an idea of how much you should expect to have to put back in.

 

[Stan H]

From reading this exchange, it seems in the top off phase the OP did not have the truck idling .

 

[Rebel.Matt]

From reading this exchange, it seems in the top off phase the OP did not have the truck idling .

Nope, I sure didn't! Which is why when I only went through 3.5 quarts of fluid I immediately turned to you nerds for the right answer. The forum did not disappoint.

 

[Rebel.Matt]

A new day, I turned the jeep on and started running through the gears. With the car running (thanks Stan H) I was able to pump in another 1.5 quarts or so, totally just under 5 total quarts, which makes me feel a whole lot better. I brought the temp up to about 85 degrees and checked again, and I had fluid leaking out, so I called it done there. I plan on doing this one more time in a few more hours, but over all I think I'm good now(?). I have a few pumps left in the 5th fluid container and haven't cracked open the 6th.

 

[Rebel.Matt]

Did it one more time at around 90 degrees and fluid was leaking out of the fill hole, which means I need to stop checking and call it good. Obviously paranoid I messed my jeep up... Everything torqued and no (obvious) leaks. Funny enough, I actually snapped one of the bolts for the oil pan and got it stuck in the thread. Thankfully I had a bolt remover kit. Replaced it with an M6 x 1.0 black oxide bolt that seems way better. Not sure how I snapped it but that was fun curveball.

 

[Stan H]

Glad it worked out for ya .
Jeep Nerds R'US at your service

 

[Maximus Gladius]

I actually snapped one of the bolts for the oil pan and got it stuck in the thread. Thankfully I had a bolt remover kit.

What torque setting did you set the bolts too? I don’t hear of too many snapping bolts unless they guessed and went too far. There should have been instructions for that with the new filter unless you didn’t replace that?

 

[Maximus Gladius]

Also, if you were curious how to get into the filter casing to check out the filter but wasn’t sure how to get it open…. This is a simple and practical way to accomplish it.

 

[Rebel.Matt]

8 foot pounds of torque for the pan and I followed the instructions for the filter which was "snug" and then a half rotation to loosen. 8 foot pounds is not a lot. I noticed that with the new gasket (the rubber one) that the pan sits a little closer to the transmission block, and I think the bolt wat hitting the block (drivers side rear on the corner of the pa). Either that or the bolt was doomed from the beginning. I don't know, but I am very careful to not over torquing things because I've made that mistake before. (I got new tires a few years back and the tire guys over torqued the lug nuts and I've had those break on me).

 

[LouisvEarlleJT]

Do we have any examples of people measuring how much they drained when doing this job? That’s just a basic step for any fluid service but it seems to never be mentioned.

Sponsored