2005 XK8

135K miles

I’m in the process of replacing the ORIGINAL transmission filter.

The bolt heads are t-27 with a very shallow depth. I took my 3/8 butterfly impact to them and they do not move.

I then got crazy and put a snap-on machine tooled t27 fitting onto a ½ drive impact and stripped out the socket hole of one of the bolts.

I then took an airchisel to this bolt and removed it.

Then I called a friend of mine and he was worried that I might either break off one of the heads or actually strip out the aluminum tranny housing. He suggested heating each bolt with a mini torch and try that, emphasizing that the air chisel would the last resort. He is a Mercedes Mechanic and close friend but he also said not knowing what metals are used on the jag version of zf tranny he was not certain what the best solution would be. (he told me that many of the MB variants have magnesium casings).



So…what is the general consensus of how I should approach this? The operation is underway and on the floor work, no lift.



jn

 

There is a video of a guy who, when doing the job you're in the middle of, stripped the 27torx... He didn't panic, drilled off the top and once the pan was off took a good (new) set of vice grips, grabbed the shank well, and turned it out - worried I'm sure but easily... The bolts don't bottom out and are TIGHT at face of pan, not in the hole or against the face of the tranny lip...

With curse words flying and a clenched tuckass,,, I would continue turning them out after giving them a smart tap with a hammer and cold chisel... See how far you can get, then, drill out (edit - the heads off) what remains... It's a right of passage, shearing and stripping bolts on a SUPER POORLY thought out fastener set up,,, in several places on the XK... I replaced mine with good steel hex bolts ordered from McMaster Carr... Good washers... Others have gone to the upgraded 40torx bolts...

That's what I would do... that's me...

heat sounds ok but I think it's a plastic based pan and very tight quarters

 

To prevent stripping any more bolts, clean them with detergent, water and compressed air to remove any debris in them that would prevent the T-27 socket from seating completely. This should minimize the amount of torx bolts you strip.

 

Well worth it to get the Torx T-40 bolts if you unfortunately have the T-27 bolts. Or go with hex bolts as others have done....

 

Many of the bolt hole go through the housing and are open at the top side. I try to spray some PB Blaster onto them and let sit overnight.

I use a good T 27 and a ratchet with a medium extension. When pressing upward with the ratchet firmly in the bolt head, give a sharp pull counter clockwise to break the bolt free,
then move on to the next. Works better than an air wrench.

 

I did this as prep work for removing the pan, but it's a bit difficult to direct the spray from underneath (a u-bend pipe on the spray can would be useful here). Engineering that doesn't allow for time as these bolts aren't torqued high.

I'd also be tempted to try the sharp blow with the hammer & cold chisel as JJJ suggests:- others have won with with this approach. I guess you can try a little heat:- the pan is plastic unless it's been replaced with a metal version, but it's going in the bin anyway.

I read of a few knackered bolt heads but no stripped casing threads.

Good luck.

 

That^^^^^
That is exactly right and prolly the most important thing written here....

 

I did this, same situation: use a chisel to first make a notch in the screw head. Angle the chisel perpendicular to the screw and gently hammer, don't try and rotate anything yet. Once you have a nice little notch, angle the chisel a bit and gently hammer the notch to produce torque.

Check eBay for a ZF 6HP26 kit that comes with the newer screws (bigger bit).

Best of luck, keep us posted.

 

Thanks for all the suggestions.

To clarify a bit;

I do have a new pan/filter

and

new t10 bolts

So ruining the old is not an issue as long as it is only the head.

When I said an air chisel, I wasn’t trying to suggest I was knocking the head off, rather I was using it to cut into the outer circumference of the head and then keep tapping at an angle to turn the fastener. (as you described Fred)

I’m going to spray them with the PB blaster right now and then tomorrow morning try to hammer tap etc. I really do not think it will work but maybe. If it fails I’m prepared to waste some atf and will simply refill the tranny with fluid, replace the several bolts I’ve butchered and then plan to handle the filter+oil at a later date when I have more time and the front suspension off for renewal.

jim

 

How many would need digging out with the trans pan in place - at this point? And how? Just curious...

Hmm... I think it will be difficult to get a hold of those old bolts with the tranny pan in place, and old bolts still holding firm... I think you'll be surprised to see that there will be a good 1/5 to 1/4 inch of bolt to grab with a good locking square nosed vice grip once the pan is off. That is unless I misjudge the thickness of the pan hole bush, to tranny face, thickness... Goodness know I could be wrong. And yes,,, the bolts are not tight (shouldn't be) once the pan bush has been removed...

But hey,,, I don't want you driving around my neighborhood with a hammer looking for me if things go sideways, lol... Do what you think is right.

 

I could not loosen any of the bolts with the t27, none of them. I used the air chisel on three of them and truth be told I could reuse two of them but why, since I have the new ones.
My 'air chiselling experience is long in tooth, certainly not as precise as a hand held chisel but control is my friend and I believe I could work my around all of them given some time. If there aren't reports of damaged threads in the tranny flange then I'm good to go but it will take time.
As I stated, if the pbBlaster over night soaking doesn't work then I'll replace those three bolts with new style and fill the tranny for the time being.

more opinions or experiences are appreciated
wj