[chef423]

2008 335i Sedan

Transmission slipping. Serviced the Mech sleeve about 3 yrs ago. After, kept hearing a 'boop' or little squeak sound when shifting into a particular gear. Now that I have added big power, she is slipping and threw a 4F8A code.

I assume its the ZF 6HP26 transmission I have? They are pretty cheap, used with a test guarantee. Better route vs trying Mech sleeve service again? Solenoids, seals, sleeve, fluid, bridge seal. All those parts etc running me $600. The used transmissions cost that and up.

[konstat]

Originally Posted by chef423

2008 335i Sedan

Transmission slipping. Serviced the Mech sleeve about 3 yrs ago. After, kept hearing a 'boop' or little squeak sound when shifting into a particular gear. Now that I have added big power, she is slipping and threw a 4F8A code.

I assume its the ZF 6HP26 transmission I have? They are pretty cheap, used with a test guarantee. Better route vs trying Mech sleeve service again? Solenoids, seals, sleeve, fluid, bridge seal. All those parts etc running me $600. The used transmissions cost that and up.

If you replaced the solenoids the first time you serviced the transmission then maybe it is the clutch packs. 3 years seems short for worn sealing sleeves, solenoids, etc. unless you didn’t do the solenoids. how many miles has it been since you last serviced?

How much power are you running? The 6HP26/28 can handle at least 600whp. Did you swap from a 19/21 to a 26/28? Didn’t think any 3 series came with the 26/28

[chef423]

Thanks for the response. Yea, I think its the clutch plates as well. I'm pushing around 500 HP or so. No swap, I just misspoke. I have the OEM transmission.

[konstat]

Originally Posted by chef423

Thanks for the response. Yea, I think its the clutch plates as well. I'm pushing around 500 HP or so. No swap, I just misspoke. I have the OEM transmission.

You could try the line pressure bump flash option in xhp to see if that helps while it’s on its last leg

[smass]

I was where you are a year ago. I ended up up going with an 8 speed swap. Don't waste any more effort on the 6 speed when the 8 speeds are cheap and close to plug and play now. Check out CANTCU.

[chef423]

Originally Posted by konstat

You could try the line pressure bump flash option in xhp to see if that helps while it’s on its last leg

Already tried that. No help. In fact, it made it worse I believe.

[chef423]

Originally Posted by smass

I was where you are a year ago. I ended up up going with an 8 speed swap. Don't waste any more effort on the 6 speed when the 8 speeds are cheap and close to plug and play now. Check out CANTCU.

8-Speed from what line/model of Bimmer? Also, I want to stay automatic. I live in LA and I am not even dealing with the stop n go with a manual. Plus, boost loss when you shift. I learned to drive on a manual and I prefer them, but not in this case. My '87 Grand National was automatic, huge boost.

I found a guy in North Hollywood, recommended by a mechanic I trust greatly and he has rebuilt 5 HP21's for the man, so he's good. BUT I would like to visit this 8-speed swap. 8-speed able to hold more power?

[chef423]

Originally Posted by smass

I was where you are a year ago. I ended up up going with an 8 speed swap. Don't waste any more effort on the 6 speed when the 8 speeds are cheap and close to plug and play now. Check out CANTCU.

Picked up on a thread for the 8HP swap. Looks like a ton of work. And I don't want to DIY this one. I do ALL my own work, but the transmission? NOPE. Not even gonna go there. IF I had a lift, maybe then, but still....

[whyzee125]

Do your solenoids, sealing sleeves, and bridge adapter first. GOod chance this solves your issue. If not, you can transfer the solenoids to a used trans to freshen it up if you have to replace it.

[konstat]

Originally Posted by chef423

8-Speed from what line/model of Bimmer? Also, I want to stay automatic. I live in LA and I am not even dealing with the stop n go with a manual. Plus, boost loss when you shift. I learned to drive on a manual and I prefer them, but not in this case. My '87 Grand National was automatic, huge boost.

I found a guy in North Hollywood, recommended by a mechanic I trust greatly and he has rebuilt 5 HP21's for the man, so he's good. BUT I would like to visit this 8-speed swap. 8-speed able to hold more power?

How much would he charge for a rebuild. As a reference point, Eriksson Industries in CT is at $3k for a full rebuild including the valve body

[chef423]

Originally Posted by konstat

How much would he charge for a rebuild. As a reference point, Eriksson Industries in CT is at $3k for a full rebuild including the valve body

Same price out here in CA. $3000.00

[chef423]

Need advice!

I dropped the car off for a full transmission rebuild BUT I didn't use xHP to flash the tranny back to vanilla. I have the Stage 3 tune with line bump flashed on the broken transmission.

DO I NEED TO FLASH BACK TO STOCK? Or will it matter?

Thanks

[whyzee125]

Originally Posted by chef423

Need advice!

I dropped the car off for a full transmission rebuild BUT I didn't use xHP to flash the tranny back to vanilla. I have the Stage 3 tune with line bump flashed on the broken transmission.

DO I NEED TO FLASH BACK TO STOCK? Or will it matter?

Thanks

It won't matter.

[chef423]

Thanks for the response.

[konstat]

Originally Posted by chef423

Need advice!

I dropped the car off for a full transmission rebuild BUT I didn't use xHP to flash the tranny back to vanilla. I have the Stage 3 tune with line bump flashed on the broken transmission.

DO I NEED TO FLASH BACK TO STOCK? Or will it matter?

Thanks

Yea I agree it won’t matter. It would make a difference if you did a valve body service only since it would affect adaptation values of the worn clutches. Remove the line bump when you get it back and should be good to go

[chef423]

Thanks for all the replies here!

Car will be done tmrw. The guy sent me videos of him explaining the issues and fixing them! ALL clutches were worn to the nub. He did the Valve Body as well. New Solenoids, seals, the works!

My custom tuner guy is pumped! He said we get to play with a fresh transmission to lay all that power down to! HAHA! WOOT!

[chef423]

Gonna give a shameless plug here, hope this is OK.

Serjik. Armenco Transmissions. North Hollywood, CA.

Serjik's Yelp rating speaks for itself. This guy is epic! Never saw a mechanic document what was wrong on video and send it to a client. But this guy did! 5-STAR!