[amc49]

The big gear bearing pulls off with a bearing puller, pressed on. And if the cover going on is not the original you WILL have to resetup the shaft end bearing preloads or you will get noise or tear up bearings on ends of shafts super quick.

The cover may not just slip all the way down that last half inch, it likely has to press tight over the bearing races. As in be 100% sure of parts placement and light whacks with a mallet to seat the cover.

And, looking closely at your parts stack, the big gear (differential drive ring) appears to have the gear on the right actually touching it like the parts stack is not fully settled down in place. Can't say positively as I haven't done one of those yet but as a trans guy from way back you go looking for such things as problems.

Don't overlook that bearing preload issue, it may turn that work into scrap. Special tool needed to figure the preloads unless one is smart enough to make up for the lack of that tool to do it another way. You don't just change covers there, they have to be matched to what you already have.

 

[a. hall]

Thanks for responding amc49. I do appreciate the information. Wasn't aware of the preload reset. I didn't see it mentioned anywhere online. I do not doubt you. If you dont mind and are willing, would you explain the preload reset and what tool I will need. I have no problem buying the right tool for the right job. Your right that one gear is touching the big one. I have gear pullers, it just doesn't look like anywhere to put it to pull old bearing. When we put the new cover on we did alternate bolt tightening to try and close the half inch. But that is when the case assembly cracked. When we took it off we saw that the upper part where the 6 bolts go had marks on edges of indents where those upper bearings go. I assume that the gears are leaning or out of whatever alignment there was. Thank you

 

[amc49]

The bearings on ends of shaft are tapered roller with angled cups that go with them. That type bearing commonly used there does not go in with a clearance, or a little extra looseness. It goes in slightly over tight, the shaft will be slightly longer than will fit in the cover bolted down solid. There is a spec in the service manual and it will be a couple thousandths or so that the shaft is longer than the case allows, it is called preload when you do that as the shaft is under a slight load not even in use. It stops noise that all geartrains can make when they go together the other way, with a clearance or slightly loose. The tapered bearing also lasts longer that way.

Any trans taken apart can be put back together using the same shim setup provided no shafts or bearings (including cups or races) or main case assembly or diff case is changed, you have to reset the preload on any changed bores.

Thinking the shims in each bore are select fit to be different thicknesses; you get the correct thickness shim to shim up the bearings race to the slightly too tight spec.

Any special tools will be called out in service manual along with how to measure for preload and the spec itself, the main differential is commonly a little tighter than the other shafts.

You commonly do not see any mention of it online as most 'experts' act like it is not important but it CAN tear the trans up. Ford does that measuring and adjustment on EVERY new trans.

 

[a. hall]

Copy that. Thanks for your time to explain all that, much appreciated. I even talked to the so called experts on a paying site and none of them mentioned this at all and all they could say was there are no instructions for the case assembly. Thanks again!

 

[amc49]

mtx75 Manual Transmission | PDF | Manual Transmission | Transmission (Mechanics)

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Only the first couple pages of a Ford service MTX-75 manual trans in a Focus but the shafts set up in a similar way. Go down just a little way to 'required shim thickness' section. Take a moment to digest that chart. They mention a shaft and the looseness or preload (tightness) of each shaft. The first one, input goes in to set at being slightly loose, the 0.05 number. They start with an open gap and insert a 'measuring shim' to take up most of the space to end up with a 'determined end float'
number, or how loose the part still is, the gap has just been quantified into something you can use to zero in on the final shim needed. Note that first shaft does NOT preload or over tight and the dash indicating it. Meaning it ends up slightly loose. The next section is the required shim thickness which goes to another page and it calls out 1.17 mm. as the desired shim and do the math. You pull the 1.00 measuring shim and use the 1.17 one and the 1.17 reduces the at first number of 22 down to 5 like needed. Still slightly loose though.

The nest two measurements are likely like yours and preloaded ones but you need the Ford service manual to both know if all are overtight or maybe not, they still have to be set up as even loose can do damage, if too loose the shaft then knocks circlips off parts to break things from impact stresses.

The next, output shaft calls for preload of 0.13 or overly tight when done. The measuring shim showed 0.33 of space to take up but you have to go a bit further to make it too tight so they use a 1.46 shim (.33 + .13 to get the preload). The third shaft does same as this one but just a differnt number as all shafts are slightly different in lengths just like the covers that go over them and why you have to do that minute work. You have to make sure any shims that fall out of cases go back EXACTLY where they came from too---CANNOT mix them u8p once they are locked into a certain location.

You can hang a bet that most trans experts do not do all that fine detail work, but then they don't pay for the damage done when the trans does not last nearly as long as it should. I've seen best of the best overlook that stuff myself and they will tell you it'll be just fine but commonly it leads to gear noise or excess bearing wear.

When I went to a major south central distributor of trans parts for literally everything and talked about doing that work and why they didn't the main manager asked if I knew how and when I said yes he tried to hire me on the spot.

 

[amc49]

In that pic you have there is the diff itself all the way down? You said a gear was hitting it and absolutely NOT right. Now that I look again it looks like your three shaft parts stack is leaning to one side like the diff is holding it up. Something is wrong there.

 

[amc49]

Wrong trans again but preloading bearings discussed.

 

[amc49]

changing bearings, final drive and shimming of the...

So since the passing of our beloved transmission builder TH, I have been left to my own devices for building up my transmission. Part numbers: Old style output shaft with 3.82 final drive $121 F8RZ-7061-SA Ring gear to match 3.82 $171 YS4Z-7F343-FA Input shaft front bearing CV6Z-7025-A Input...

www.newcougar.org

Again wrong trans but preloading info halfway through it. Thinking you will have fits finding exact info on DSP6 as nobody takes them apart beyond the double clutches usually and that is too much for many of them anyway.

Hope you can find a manual, looking for a Focus manual might get you there but what if the trans is complicated enough they simply don't put a full trans manual in the car manual? Like Nissan did with the CVT trans, they no longer include anything in service manuals at all other than how to change the fluid.

 

[a. hall]

I showed my neighbor who is helping the info and he pointed out that I put the wrong image for bearings. It is very similar but if it matters the correct trans is an MMT6.

 

[amc49]

The MMT is totally different from the DSP trans of courtse. The same shimming thing is likely done on both though as they button those shafts up in a way that requires it.

 

[a. hall]

Got it. I was trying to take a short cut and thought I grabbed an image from the internet that was the right one. My apologies for wasting your time. This is my actual gear box...

 

[amc49]

Doesn't matter I still see shafts that likely need similar treatment. Shimming I mean.