MY TRANSMISSION REPAIR 8hp90

[hellno]

Unless they have some sources that use thinner plates to increase the clutch pack capacity I don’t see much more that can be done , coleen steels would be helpful but I wasn’t able to find any for this unit but thinner steels can sometimes be counter productive because the steels also play a part in the cooling of the clutches the c clutch steels are thick I wish the e and d clutch steels were ,
The Valvebody i guess is a possibility but when you start messing with the calibration of these units it usually doesn’t work at all and builders run into shift timing issues like not shifting at all or too much overlap or bind ups between shifts

 

[cole3986]

Solenoid pressures can also be controlled in the tune.

Yes, line pressure and the lock up on the converter are adjustable.

 

[cole3986]

this may be the reason the clutches burnt up lol

Why your A8 is slipping and others are not (including mine) is as clear as muddy water.

 

[hellno]

Solenoid pressures can also be controlled in the tune.

I noticed that as well I’m going to see if curt is willing to change the tune But what concerns me is if you go in change shift pressures in one clutch you might also be Changing shift timing as in the time between one clutch releasing and the other clutch applying not enough and you have overlap ( bind up) too much and you have a clutch releasing and the other clutche not coming on fast enough would cause a flair up which in both circumstances can cause clutch burn up so I think all clutch pressure would need to be changed together

 

[Blown7]

Are going to run Mopar fluid or change it up to real hydraulic fluid like we do in real drag cars......???

 

[hellno]

Why your A8 is slipping and others are not (including mine) is as clear as muddy water.

I don't know about others but from talking to curt these transmissions are having problems,,as I stated in the post earlier I believ I caused mine

 

[Blown7]

I noticed that as well I’m going to see if curt is willing to change the tune But what concerns me is if you go in change shift pressures in one clutch you might also be Changing shift timing as in the time between one clutch releasing and the other clutch applying not enough and you have overlap ( bind up) too much and you have a clutch releasing and the other clutche not coming on fast enough would cause a flair up which in both circumstances can cause clutch burn up so I think all clutch pressure would need to be changed together

Changing clutch timing is the stuff of powertrain engineering... you absolutely need those stock fill time numbers... Is Jerseyboy around????

He really knows that stuff....

 

[hellno]

Are going to run Mopar fluid or change it up to real hydraulic fluid like we do in real drag cars......???

that a good question I ordered the fluid but I was curious if theres a fluid that will make the shifts more aggressive ,I remember using b&m trick shift atf back years ago in my 700r4 and 350 transmissions,what fluid are yall using if I may ask??

 

[hellno]

I believe the clutch and steel module I have is the same one that SHR uses
there isn't any shift improvement kits for these ,its all done thru the tuning now

 

[hellno]

n ow I noticed SHR ADVERTIZES KOLEEN STEELS I WLL SEE WHO IS SELLING THEM

 

[Blown7]

that a good question I ordered the fluid but I was curious if theres a fluid that will make the shifts more aggressive ,I remember using b&m trick shift atf back years ago in my 700r4 and 350 transmissions,what fluid are yall using if I may ask??

No one here ventures beyond stock stuff...No one here is on the cutting edge.... by a long shot

But John Deere Hyraulic fluid is what I use in my Hellcat powered TH400...

 

[hellno]

No one here ventures beyond stock stuff...No one here is on the cutting edge.... by a long shot

But John Deere Hyraulic fluid is what I use in my Hellcat powered TH400...

IN A TH400 I WOULDNT HAVE AN ISSUE WITH TRYING SOMETHING ELSE BUT THE 400 DOESNT HAVE THE ELECRONICS THE HELLCAT TRANSMISSION HAS ,THE PROPER FLUID AND VISCOSITY PLAYS AN IMPORTANT PART IN SOLENOID FUNCTION AS WELL AS FRICTION COEFFICIENT

 

[Blown7]

IN A TH400 I WOULDNT HAVE AN ISSUE WITH TRYING SOMETHING ELSE BUT THE 400 DOESNT HAVE THE ELECRONICS THE HELLCAT TRANSMISSION HAS ,THE PROPER FLUID AND VISCOSITY PLAYS AN IMPORTANT PART IN SOLENOID FUNCTION AS WELL AS FRICTION COEFFICIENT

Well then the next go to is Redline D6 ... Used by Coan and alot of others..I used it in my NAG 1

 

[hellno]

I DID SEE REDLINE .IT DOES HAVE A GOOD NAME FOR ITSELF

 

[hellno]

I ALSO HAVE THE BG SYNTHETIC FLUID WHICH WORKS WELL IN THE ZF6HP TRANSMISSIONS

 

[Blown7]

I DID SEE REDLINE .IT DOES HAVE A GOOD NAME FOR ITSELF

Rossler recommends a good hydraulic oil. among other.. lets face it they are the King in Auto trannys....

 

[Blown7]

Redline is recommended here


https://www.ramforum.com/threads/zf-8-speed-with-amsoil-anyone.112336/

 

[hellno]

Redline is recommended here
Thanks that was an interesting read 👍

https://www.ramforum.com/threads/zf-8-speed-with-amsoil-anyone.112336/

 

[motorhead]

But John Deere Hyraulic fluid is what I use in my Hellcat powered TH400...

Same thing I ran in the TH400 in my Turbo Buick. JD Hygard comes in a high and low viscosity formula, and you can loosen up or tighten up a torque converter with each version. You can tint it with normal ATF.

Getting less than 20K miles out of transmission is never fun.

 

[hellno]

Dang dude, fast work and great info. Auto tans make me nervous and I leave that to the pros like you. I kinda understand the clutch diagram, but can you explain it? So E and D clutches were slipping and those appear to be used in just about every gear.

I had some down time at work today and dug in to some of the trans tuning stuff. There is a TON of stuff you can do in here. Admittedly a lot of it I don't understand because I'm no auto trans expert, but the two of us could probably come up with some good info.

You can definitely set shift pressure per gear as well as clutch ramp time, torque converter fill time, and a bunch of other stuff. I'm gonna look at it some more tomorrow and compare mine to a Demon crate tune and a RE stock tune.

If you look at the clutch application chart you will see that the A and B clutches are used as brakes as you can see this transmission hasn’t any bands or one way clutches A and B is used in every gear except 6th where the ratio is 1to1 A and B are holdings clutches as to where the c, d and e clutches make the gear changes the only explanation I have for the c clutch not showing any issue is the thickness of the steel maybe being that a thick steel also helps keep the clutch pack cooler, also c always has two other clutch packs on when it’s applied where the E clutch pack comes in in 2nd and the D clutch packs comes on in 4th