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Biotoxic

ZF6HP26 Gearbox upgrades and torque converters..

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Exedy used to do an uprated clutch kit for the 6HP26 (or maybe the Ford equivalent).

 

The Ford 6R60 or 6R80 gearbox is very similar to the 6HP26 so there may be some upgrades there.

 

If your gearbox is the pre-LCi I think the oil pump is a bit of a limiting factor. It can't generate the oil pressure to force the clutches together as well as the revised oil pump in the LCi gearboxes.

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Looking to build a sub 500 whp gearbox box myself,with reliability in mind. Mostly what happens is torque converter develops a slippage. Slippage causes heat, gearbox doesn't like it. Anything above 100°C is bad for a gearbox in a long run. I still have a lot of things to do beside gearbox, but main things to consider is cooling and gearbox oil change no less than for every 70k miles. With a stock cooling system you get a plastic sump. I got a Metal sump for two reasons: 1. It cools down transmission better than a plastic sump(which is more fragile than metal) 2. It has a separate oil filter so you can re-use the sump(some kits offer different sump bolts so it's possible to re-use them as well) When changing sump only filter element and sump gasket requires changing. Money saving in a long run...

 

Part wise first gen gearbox has a bearing issue, so they need to be changed to a uprated ones. Oil pump can be changed to uprated one from 6R80 but there are two types with different spline count and torque converter fixings.. I will look into it as well.  There is a guy from mainland (Doug) who makes uprated/improved TC who uses a kevlar plates instead of normal friction material amongst some other improvements(already enquired about what exactly, it will be a last part of my build so will know in about a month or so)  

Clutch wise Exedy stage 1 clutches are available and they are rated to  ~500hp, I initially thought about getting a stage 2 but they are rated to ~1000hp...... So... Stage 2 isn't quite needed.

 

Mechatronics: zip kit with replacement solenoids(if they need to be changed) and some other valves(if needed) has to be done, but it depends on the overall health of the gearbox. 

 

 

 

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So it's been a good while since I posted something regarding the 6hp26.

A bit of what I've done so far:

 

I opted for spare gearbox out of another 535d from scrapyard since I want to see "what's what" so to say.

 

Word of advice!

A torque converter(TC) can be refurbished once. If it is already refurbished by someone it will be marked somewhere on the TC. It could be a + or - or a dot stamped near the welding line. 

I got a gearbox that had a TC refurbished and clutches replaced with solenoids as well. Wasn't the best job as the bushes wasn't changed. 

 

Do research before you do anything, not everything is shown  on YouTube. 

Even the manuals sometimes shows a different drawing or step to do. 

 

 

 

Anyway 

Finished with the mechatronics rebuild/upgrade today. A lot of it makes sense now. 

End plug kit with O-rings seals the bores tighter than just a plain aluminium plug thus increasing the pressure. Pressure loss is a killer of gearboxes, same goes for "lifetime oil"... so to say, one thing leads to another... 

Take a lot of pictures if you decide to go ahead with it. 

 

I used a Sonnax zip kit with sonnax separator plate, ZF solenoids. The rest of the stuff is mostly at the ZF's overhaul kit. 

 

If done the first time it's a weekend job if you start it on Friday and you have parts you need. Back on road at Sunday afternoon. Can be done faster. Cleaning takes a lot of time but it has to be done. 

 

Few pictures as well. Mostly the ones with the uprated parts. 

 

Thanks @JasonH for pdf files. Contained some information I've haven't read before. 

 

 

 

 

 

Screenshot_20201215_222251.jpg

Screenshot_20201215_222327.jpg

Screenshot_20201215_222353.jpg

Screenshot_20201215_225853.jpg

Screenshot_20201215_225839.jpg

Edited by Biotoxic

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On 04/01/2021 at 05:04, Biotoxic said:

Finally, after a lot of delays it's done. 

 Installing and testing after 3rd lockdown. Will update with pictures sometime later on. 

 

Screenshot_20210103_180514.jpg

Any details on your 6hp26 rebuild? 

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Gearbox has been swapped over and I did 65 miles so far on it. About 60 miles took just to follow(kind of) adaption procedures. Quite a lot of traffic on the roads...

 

Before I programmed the replacement gearbox to the car I read the adaption values including the mileage.

 

So the gearbox I got from the scrapyard was done 65k not too sure if it displays km or miles.

and adaptions on E-clutch was already 750mbar... 

 

My conclusion from what I've seen is:

750mbar is not an end of the gearbox but sure is the first sign of failure.

All the parts worn out eventually. In pre-Lci's the weak link are bushes, but what happens is as the clutch disks wear out they deposit a fine grain-like material, sort of dust. Over time and mileage, they add up fine sandpaper-like material too small for a filter to do its job. If the oil is not changed it will gradually speed up the process of a bushing failure due to the way journal bearings work and the material they are made of. More of it here, a nice 26 page read, well worth it.

If you don't feel like reading the journal bearings operate best at optimum speed and heat amongst other things.   So a ''liquid sandpaper'' flows past the shaft where the bearings are and due to the physics of the bearing and a shaft it wears the bearing out in an oval shape, once it's done it the E-clutch itself will start to wobble excessively and will wear out unevenly the first and last clutch disk as seen in the previous images I took, from there it will get worse up to the metal and metal contact resulting in a toasted E-drum and transmission error.   

 

If you join a motorway and transmission gives an error, then it's time to consider your options. If you tow something it's the same.

 

My own experience with the gearbox: I got it with a worn e-clutch but it has lasted for a 3 years give or take although I have to mention that I changed the oil after a year of ownership and it was done about 3 years before I bought the car as the previous owner did a lot of motorway miles. Never had a transmission error as I learned the E-clutch is applied in 4th 5th and 6th gear. Hard pulls still can be done in the first 3 gears, not the 4th 5th, and 6th. to preserve the gearbox for longer. I did a xHp stage 3 tune on the gearbox from the second of November until yesterday. the only increase in pressures was in  B and C clutches.

 

 

 

Issues I need to sort out:

Transmission is jerking and rough shifting in 1-2 2-3 and 4-3 3-2-1 but they are getting milder as the mileage builds up. I was expecting a bit softer gearchanges, but it might be down to uprated clutches due to more grip and different clutch material than oem. I reset the adaptions after the first 6 miles as it was quite bad, felt like somebody slowed down the car for a split second and let it go... 

Partial adaption procedure was followed, but to do it spot on would require a race track... My software version is P so to do the procedures I drove about 60 miles so it's not like you could find a nice long stretch of A road and do it...I am guessing a 2 am on a motorway on Sunday morning would be quiet enough to do the second stage of teach-in the procedure...

 

 

 

Images:

The first one is the replacement gearbox before programming and adaption reset.

The second one is before replacement gearbox  adaption reset

The third one is  after I got home from a 65-mile drive fallowing the teach-in procedure

 

 

Will do a town driving tomorrow and hopefully, the gear changes will become softer and less noticeable.

 

P.S. For some reason I am getting a fuel filter error as ista says it's clogged an alternator error and glow plug module error(although they are non-existent)... will look into it

 

 

 

 

replacement gearbox mileage.jpg

replacement gearbox adaption values.jpg

after 65 miles.jpg

Edited by Biotoxic

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When I had harsh gear changes I changed the oil and reset all of the adaptations. I then followed the teach in instructions almost perfectly....and the gear changes were terrible. I used the car for a few months but once learnt bad it seems the adaptation couldn't be unlearnt. So I reset the adaptations again and drove gently for a few hundred miles and the adaptations were perfect.

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Follow up:

Done 205 miles, adaptions getting much better, still have 1-2 harshish shifts and 4-3 ish downshifts. Had a terrrrrrrrible vibration on different speeds mostly when acceleration. Narrowed it down to a TC judder form a reconditioned unit... The one it came with a gearbox. Since the gbox has done 65k miles I though the TC was reconditioned about 10k miles ago so should be ok, but since my Luck from 1 to 10 is about 1.5 then it didn't worked as the whole car shakes when. It tries to apply, mostly from 3rd gear and up.... Its getting a bit better now but it also has a fluctuating rpms so it will have to be changed.

 

Adaptions:

Screenshot_20210121_182606_com.rbttuning.xhpflashtool.thumb.jpg.dcddfc20272189bad47556b03af50b36.jpg

Edited by Biotoxic

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Agreed it's bad news about the T.C , must have been a poor quality re-furb

Did you fit all new solenoids? & do you think having do it yourself 

that I could do the zip kit with the gearbox in place?

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Ordered a uprated TC so it matches the title of this thread.  I fitted new zf solenoids, sonnax separator plate and sonnax zip kit. Get the seal tubes and mech adapters as they come with overhaul kit or are available separately. 

If you start on Friday day you'll be finished by Sunday. Do take a lot of pictures and watch Gary's videos before you do it as there are small check balls that could fall out when you open the mechatronics . The only thing I didn't do I didn't cleaned the valve body seals off with a extra fine sharpening stone.. Zip kit includes the spring valve to check the vacuum leaks, but the vacuum pump from sonnax costs quite a lot so it's one of the parts will be left over. 

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Calculated expenses without extra tools and replacement gearbox. 

 

Stage 1(uprated parts without hybrid elements) : 
Fluid x5l =89.20 (bought extra, just in case) 
Fluid x7l + metal sump =205
Solenoids =273.87
Upgraded bushing kit from US =113
ZF overhaul kit =149.22
Separator plate =64.10
Zip kit =129.65
Uprated clutch packs from US=341.53 
                                                    =1365. 57
Uprated TC =525.00              =1890.57

 

Fluid change + mechatronics parts if valve body is ok = 672.62

 

 

Not too bad. 

 

P.S. Shifts now are way smoother, still driving gently as I can fell the TC is on its way out. 

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Screenshot_20210204_123835.thumb.jpg.1721ed4d49d775b96f84e0eca6ef409a.jpg

Adaptions before I changed the torque converter and now with the uprated TC

Screenshot_20210206_185427.thumb.jpg.8d3e54573ef85c88deb431bced4f511e.jpg

 Haven't had a chance to drive on the motorway so the E clutch pressure will definitely change. Will take it for a longer drive on Monday, I'll check the adaptions and then it's time for a xhp stage 3....

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Biotoxic, thank you for all the very useful information. I have a car with a 8HP45, currently at 92k miles. Did a fluid and pan change with LG8 at 70k miles. The adaptation value for clutch C is +550 mbar, which is high. Do you recommend I change the fluid again, +change the solenoids, +get a Sonnax zip kit? Thanks for your help.

 

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33 minutes ago, chipguy said:

Biotoxic, thank you for all the very useful information. I have a car with a 8HP45, currently at 92k miles. Did a fluid and pan change with LG8 at 70k miles. The adaptation value for clutch C is +550 mbar, which is high. Do you recommend I change the fluid again, +change the solenoids, +get a Sonnax zip kit? Thanks for your help.

 

Hi. Sorry to barge in. Fluid change wont do any good at this stage. Clutch pack is worn now.  Your valve body is has one or more worn valves and there is loss of oil preassure and as a result clutch pack started to burn. Valve body can be repaired by turning valve seats oversize and installing oversized valves. Also bushes are going to be worn to so its probably best to do rebuild,but it is expensive job. Zf8hp45 is is not very strong gearbox especially if car was used for towing. What engine your car has? 

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12 hours ago, chipguy said:

It is a 2012 528i with N20 engine. Did not use for towing.

 

Strange how its worn like that at low  ish mileage.

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7 hours ago, Yuri84 said:

Strange how its worn like that at low  ish mileage.

Could there be a leak in the Clutch C circuit, either the solenoid, the valve or the VB separation plate? I read the transmission does not measure pressure directly, it calculates pressure by measuring solenoid current, rpm etc.

 

Either way, I plan to keep an eye and see if the number gets worse.

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10 hours ago, chipguy said:

Could there be a leak in the Clutch C circuit, either the solenoid, the valve or the VB separation plate? I read the transmission does not measure pressure directly, it calculates pressure by measuring solenoid current, rpm etc.

 

Either way, I plan to keep an eye and see if the number gets worse.

Can be a lot of things. I think solenoid would throw a fault code i there would be problem,but i am no transmission specialist. Just keep an eye on it. Check fluid level,maybe its low.

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1 hour ago, chipguy said:

Thanks, I will check the fluid level first.

Also when you check adaptations,have a look not only on pressure values,but also at filling times. If values are high then that a good indecation of loss of fluid pressure inside transmission.

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