DIY 335IX built motor/trans single turbo build

nyt

Corporal
Sep 15, 2019
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2010 335xi
Ok, nizpro issues figured out.

They use a custom bushing they turn down for a tighter fit, which was just never communicated.

They also grind the nubs off the needle bearing carrier, which they missed missed.

They're sending me a fresh bushing next week, so I won't have to machine anything and can continue this build. I'll just have to wait for the bush for final assembly.

I guess I can get started on soaking the clutches and replacing soft seals this weekend.
 

pysical

Sergeant
Jun 16, 2017
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2009 335xi E90
Hey not sure what power level I was at. I would imagine 750+. Ran like a champ until the fire. So once I get it all rebuilt I will be back at it.
 

nyt

Corporal
Sep 15, 2019
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2010 335xi
Little progress tonight, just replaced some seals. I still have to do the c/d brake and some other misc seals, but I need to either make or buy a tool. I made a quick one for the b clutch, but the c/d are bigger and I didn't have any steel stock handy that would have been suitable.

pump


a clutch




b clutch






 

nyt

Corporal
Sep 15, 2019
170
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2010 335xi
Ok, nizpro not coming through with the bushes. I'll have to get some new PD bushes then ream. Yay :/

I also need to track down an axial needle bearing (0735368091) that nobody online in the US seems to have, like an $8 part that's causing me headache. Will call ZF tomorrow and get a list of resellers.

Also, the Nizpro intermediate shaft has an oil restrictor, but the stock one doesn't. Not sure if I should pull the one from the Nizpro or not. Apparently they say all the stock shafts they've seen have one. I figure I'll ask ZF about it. Might be because this is the 6hp21x with the extension for the transfer case, dunno.
 

nyt

Corporal
Sep 15, 2019
170
172
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2010 335xi
Still waiting on some bushings. USPS was supposed to have delivered Saturday, but didn't. At this point I just need to replace the intermediate and input shaft support bushings, ream the one in the input shaft, swap the clutches, and replace a couple of soft seals in the transmission case.

Got the issue with the thrust bearing on the back of the E basket dealt with. Finally got a replacement in the mail. I just had to grind down the nubs.





Otherwise, C/D brake soft seals replaced.







 

nyt

Corporal
Sep 15, 2019
170
172
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2010 335xi
How much shipped when done ?😅

Lol. You can have any trans shop do this work. Nothing is that complex, you just need the parts, really. I can put together a write up when it's all done and working, but there are other options now that may be more cost effective. There's a 6hp28 adapter in the works and HTG has a controller for 8hp. There are 8hp70s that came on N55s (active hybrid in 3,5,7 series) that will bolt up to an N54. That said, the shafts from Nizpro were just over 3K shipped from AU to US. I had to do some machining after receiving them as well. Aside from the shafts, the clip retainer on the E basket is machined out an extra 1mm (this inside machining in a tight space can be tricky, but Nizpro can do this if they can be bothered), 3mm of material is taken off the face of the E piston, the back of the E piston in the center is machined to clearance the welds (vid at bottom of first post), and a 2mm spacer is used to keep the oil dam below the lip of the E piston. I can now fit 8 of the Alto/PD frictions and 9 of the steels for the E clutch, no top plate or spring plate, though. The bushing seated in the input shaft also needs to be reamed for 1-1.5 mil clearance.

The rest of the trans build is standard bushing and soft seal swap with a zip kit and the Alto/PD clutches from PR.
 
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SlowE93

Lieutenant
Jul 2, 2017
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E93
Lol. You can have any trans shop do this work. Just need the parts, really. I can put together a write up when it's all done and working, but there are other options now that may be more cost effective. There's a 6hp28 adapter in the works and HTG has a controller for 8hp. There are 8hp70s that came on N55s (active hybrid in 3,5,7 series) that will bolt up to an N54.
Yes, I saw that option in the works.
However, you are meticulous like me.
I wouldnt trust a trans shop ATM.
 
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nyt

Corporal
Sep 15, 2019
170
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2010 335xi
Yes, I saw that option in the works.
However, you are meticulous like me.
I wouldnt trust a trans shop ATM.

Could always DIY. It's not a difficult job. Just needs like $300 in tools (press, bushing tool, spring compressor, bushing/bearing puller)

A good trans builder can handle this no problem. Seriously, they've done this far more times than I have ;) The only thing special about this rebuild is the input/intermediate shafts and E clutch assembly.
 
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nyt

Corporal
Sep 15, 2019
170
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2010 335xi
*sigh* more top quality work from nizpro...


oem:


nizpro:


Also got a couple of the Sonnax bushes for these shafts.



3d printed something real quick to set tail shaft seal to proper depth...



 

nyt

Corporal
Sep 15, 2019
170
172
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2010 335xi
I got some time today, so the 6hp21 is reassembled.

Here are pics of the process

PD/Alto frictions



Soaking in atf1



While that was going on, I figured I'd check the E drum and make sure everything was god since I hadn't had that apart in a while, just wanted to check the o-rings.







All good, back together.




Case nice and clean



Tail shaft



Tail shaft installed



Rear planetary gears



Rear planetary gears installed



OEM D clutch stack



PD/Alto D clutch stack



Checking tolerance



OEM C clutch stack



PD/Alto C clutch stack





C/D brake installed



C/D brake lined up properly



OEM B clutch stack



PD/Alto B clutch stack





B drum installed



OEM A clutch stack



PD/Alto A clutch stack






OEM E clutch stack



PD/Alto E clutch stack for Nizpro input and intermediate shafts with extra clearancing





A drum on input shaft



A drum, input, and intermediate shaft

 
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nyt

Corporal
Sep 15, 2019
170
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2010 335xi
A drum, input, intermediate shaft with the A hub/sun gear shaft in place








Installed into case








Oil pump installed








Can see here it's seated fully into the case





Seals








Valve body installed





Valve body connector seal


 

nyt

Corporal
Sep 15, 2019
170
172
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2010 335xi
Nope, but im sure you can delete that part off the trans for me 😅😅😅

lol, they're actually different cases entirely. Anyway, looks like there's a 6hp28 conversion kit on the way. You could probably drop one in, use XHP for additional pressures/programming, and be good to go. It's not worth doing a 6hp21 build at this point. The shafts from Nizpro are expensive and annoying to get. Then you need additional machining, etc. I have all the info to deal w/ the Nizpro shafts available now and in this thread I think, so that's at least a big hurdle dealt with, but it's like 3k for the shafts alone.


This is the normal 6hp21



This is the back of 6hp21x



And you can see it with the transfer case installed

 
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SlowE93

Lieutenant
Jul 2, 2017
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E93
lol, they're actually different cases entirely. Anyway, looks like there's a 6hp28 conversion kit on the way. You could probably drop one in, use XHP for additional pressures/programming, and be good to go. It's not worth doing a 6hp21 build at this point. The shafts from Nizpro are expensive and annoying to get. Then you need additional machining, etc. I have all the info to deal w/ the Nizpro shafts available now and in this thread I think, so that's at least a big hurdle dealt with, but it's like 3k for the shafts alone.


This is the normal 6hp21



This is the back of 6hp21x



And you can see it with the transfer case installed

Yeah, im waiting to see development for the 28 !
 

nyt

Corporal
Sep 15, 2019
170
172
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2010 335xi
Got a little work done today. I put the oil pan on the transmission, was waiting for fresh bolts. I also installed the diff brace. I really want to put the engine and trans back in the car, but I need to strip and treat the subframe, but it's in the 20s outside... Considering just paying someone to blast and powder coat it...