Repair-It

kevm14 wrote: ↑Tue May 07, 2024 10:24 am

rpaoness wrote: ↑Tue May 07, 2024 7:26 am Also on the transfer case encoder - I think I should see if I have any encoder related codes before I drop $120 and hoping for the best.

I think we need to swap scantools again and you can add Jeep to the Launch tool.

Agreed. I think code-reading is appropriate before I start throwing parts at it.

kevm14 wrote: ↑Tue May 07, 2024 10:25 am

rpaoness wrote: ↑Tue May 07, 2024 7:28 am Also, why is the forum time stamp an hour off from Eastern time? Weird.

That's actually a local user setting. It is in the user control panel. This link MIGHT work for you: ucp.php?sid=b8c54c04de488d13fb67c5cbf0a1a2f1&i=372

That link worked and I updated it.

https://en.wikipedia.org/wiki/ZF_8HP_transmission

Related GM 8L transmission

Hmm. I tried looking into this a year ago and never got to the bottom of it.

https://en.wikipedia.org/wiki/GM_8L_transmission

Both gearboxes are based on the layout of the ZF 8HP transmission from 2008, with the only difference being that gearsets 1 and 3 are swapped.[3]

So I guess....architecturally similar (and not even identical)? And probably the rest is different (valve body, programming, torque converter). So I guess it's a relative but certainly not an identical twin separated at birth.

https://www.transmissiondigest.com/8l90 ... nsmission/

When GM developed the 6L80/6L90 transmission series, they were loosely based upon the ZF 6HP family of transmissions. The 8L90 also has a ZF thumbprint on it, though somewhat less than the previous six speeds. One welcomed departure from ZF was the absence of an internal TCM in the GM units.

That is super weird to me.

Although, I did note that the 5L50 in my STS was TOTALLY different than the 6L50 in our SRX. And I had never heard of ZF-relation on the 6L series. Sounds like the 8L is even less. So...this is not much of a relationship. I guess I could read the article at some point.

Ok - so pan options. The ZF aftermarket application sheet shows this as the right kit:
https://aftermarket.zf.com/en/catalog/p ... country=US

These guys show that kit at $156 (currently out of stock) + $10 shipping. So I think this is what I want to order, since it's "real" ZF.
https://www.idparts.com/transmission-fi ... -5251.html

They also have a "kit" with 6 liters of Rowe 9008 oil for $217 (+$10 shipping, pan also out of stock), or about $9.80 a quart. I can't figure out if Rowe 9008 is better or worse than any of the other options...
https://www.idparts.com/automatic-trans ... -5491.html

They appear to have 9000 "generic" ATF and 9008 "reduced viscosity" ATF, which continues to support your arguments, but I do wonder if the viscosity reduction is at the expense of transmission life...

For life, I may be "best" off with the MaxLife fluid, as long as I'm confident-enough in the internet wisdom of lots of 8HP70D's running MaxLife to many, many, many miles.

Rowe has several ZF approvals on other fluids, just no approvals noted on the 9008 ATF.

Shipping goes free over $200, so the delta cost for the fluid is only $8.73/qt for the 9008, but I'm not sure it's better than Maxlife.

rpaoness wrote: ↑Thu May 09, 2024 9:33 am They appear to have 9000 "generic" ATF and 9008 "reduced viscosity" ATF, which continues to support your arguments, but I do wonder if the viscosity reduction is at the expense of transmission life...

For life, I may be "best" off with the MaxLife fluid, as long as I'm confident-enough in the internet wisdom of lots of 8HP70D's running MaxLife to many, many, many miles.

Yeah I didn't say the ZF 8 runs low viscosity fluid. I feel more comfortable with Maxlife on the ZF but only if you change all of it....

I think the Rowe 9008 implies that Lifeguard 8/9 are relatively low viscosity. Not sure what to make of that though... Just need to decide if the "bundle" is worth it or stick with the MaxLife... I'm thinking stick with the $6/qt MaxLife for the ZF since internet wisdom says its OK.

rpaoness wrote: ↑Fri May 10, 2024 8:17 am I think the Rowe 9008 implies that Lifeguard 8/9 are relatively low viscosity.

https://aftermarket.zf.com/remotemedia/ ... d-8-it.pdf

26 cST @ 40C. That is up near the "normal" 28-29. The MB 236.15 and 236.17 are like 17-18. I think there are now probably other low viscosity fluids that Maxlife claims compatibility with. But as I mentione before, at the time the 236.15 came out, it was considered the lowest viscosity ATF in the world. This would have been slightly after the original release of the ZF8. Again it coincided with the option code A89. 2011-ish.