25 replies to this topic

[lildeucecoop72]

I think I have angered the mini-gods.   It seems that every part of this gearbox build is a challenge, but learning all the time!

Forgive me if someone has posted this problem before, I tried to search but did not find the exact same problem.

 

I am looking at the end float on the idler gear and when measuring with the feeler-gauge one side (toward the front of the car) between the thrust washer and idler gear and this showed a perfect enfloat. 0.003" - 'Great!'! 

I then tried to check the other side of the idler gear (direction towards the back of the car) and the 0.003 feeler gauge would not fit. I could just get 0.0015 in. Basically the gear/shim isn't squarely mating with the box. 

 

I followed the procedure, and used a pinky orange gasket, tightened the bolts to 25nm (18ftlbs). Checked that everything turns in the box with no binding or tight spots.

 

 

I guess this isn't normal should be addressed in some way? Or am I OCDing again and I should just measure from the top middle and say 'yupp job done' if I hit 0.003?

 

Just for 'fun' I ran some tests with different combinations to try to work the problem, again following the procedure each time. 

I changed the thrust washers,  and the idler gear (used) and another transfer case which still had its idler bearing in it (I have spares of all of these) all with similar results, such as 0.006 vs 0.002. 

 

I have heard of transfer cases being out of alignment, but given the result is near identical with both? I guess it's possible but how likely?

 

At first, I thought it was the idler gears bearings, that they are not true.
The idler bearings are new Toyos, bought from Guessworks. I carefully put this in using a hydraulic press standing the part square and slowly pushing them down checking as I went. Also there is a small amount of play between the idler and the bearings so even if not quite true there should be some allowance for this, (though not ideal)  but being that the bearings are in OK I must assume they are true and that can't go in any other way.
 

The other 'variable' is the gearbox case itself on the thrust washer mating surface. I had slightly damaged this when extracting the original bearing back in january, there being some ring marks from a puller when I stupidly tried to remove the bearing with the circlip still in place!  To remedy this, I got some very fine grit papr and put that against the flattest surface I could find and carefully sanded the face to remove the lines. I guess it's possible I could have ground one side a bit more over the other (not true to the rest of the case), but as I said, I was careful with this in mind. I also checked this surface with a straight edged metal ruler  against the flat sides where the gasket goes, and this looked to be pretty true and square.

 

So, I am scratching my head here, and hoping I have done something silly, rather than it being a massive endeavour to put right.

 

Any suggestions?

Edited by lildeucecoop72, 10 May 2023 - 06:29 AM.

[Steve220]

You need to measure it with 2 feeler gauges ideally.

[lildeucecoop72]

You need to measure it with 2 feeler gauges ideally.

 

Thanks for your reply Steve220. I'll give that a try.

 

How will that help if the idler doesn't 'rock' as far as I can tell?

[Steve220]

You put one either side of the shim to make it parallel. Work up from minimum tolerance. If you can't get 2x 3thou feelers in, then you need a thinner shim.

[Spider]

What did the wear on the thrust faces in the cases look like ?

Even or lop sided like this ?

 

[lildeucecoop72]

Hi Spider, here is a pic fresh off the engine taken back in december and before I cleaned it up. (please ignore the finger pointing to the seal, it was a ref to something else)

I can post another pic tomorrow, but as far as I can tell the wear is even, but will double check that.

 

 

 transfercase.JPG   84.84K   0 downloads  transfercase_c_u.JPG   61.79K   0 downloads

 

and here is the other side on the case before and after I carefully ground it to remove the lines from the puller damage:

 

 case.JPG   33.05K   1 downloads  case2.JPG   68.36K   4 downloads

Edited by lildeucecoop72, 10 May 2023 - 09:52 PM.

[Steve220]

That transfer housing is chewed. It takes the brunk of the load when you floor it and is usually the one that dies.

[Steve220]

For reference, this is before and after a shim stuck to the idler and chewed mine up.

https://imgur.com/a/jkw7g1P

https://imgur.com/a/xhuzJ2f

[lildeucecoop72]

For reference, this is before and after a shim stuck to the idler and chewed mine up.

https://imgur.com/a/jkw7g1P

https://imgur.com/a/xhuzJ2f

Thanks  Steve220,  whoa yes that is a horror story you have there, but good end result! Did you ned a new box?

I had a similar (but worse damage) experience 14 years ago resulting in new box, and transfercase. The case and box you see have been merrily propelling me along OK for 14 years, and set the endfloat correctly that time (though i admit i didnt used 2 feelers) Last autumn after abnormal diff noises, I open to investigateand found there was pitting on the idle gear shaft, but the noise came from the diff bearings,
So I decided to do a a total diff/gbx rebuild since I had it all out!  I am determined to get the idler endfloat right again this time too being such a critical failure point, but didnt realise it would all take so bloody long! 

 

As to the wear on my case, I figure that as long as it hasn't gone too far in, worn to one side (such as Spiders pic shows), dug chunks out, or physically hit  or started to kill the bearing I think its OK - as long as you correctly set the endfloat with an apropriate thrust washer(s). Though agree from the pic it could look better/smoother, I think its at least worn evenly, but will check that. I've since cleaned it up (a lot of what is in that pic is muck) and will post a pic a bit later.

 

Looks like both you and Spider have the shiny nice A+ variants. with the bigger bearings and oil channels, which I would guess will impove the lifespan if correctly set up :)

[Spider]

This is an earlier type that has a much bigger thrust area. I've seen far worst - in these early types - as far as it being chewed and go on for a long while in that condition, from experience, it's also not as bad as it looks. However while it's all in bits, I'd dress it (or have it dressed).

 

The shaft on the Idler Gear and it's bearings with these do need to be in good order though.

[lildeucecoop72]

I have a new idler gear to replace the pitted one. :)
Here’s a better pic of the idler thrust face on the transfer case:
 IMG_2271.jpeg   58.89K   1 downloads
 IMG_2272.jpeg   66.91K   0 downloads

Also still doing some tests, but after placing a flat edge against the flat gasket face on the box, I observed a 0.002” difference on the thrust surface. Not sure if this test is relevant, but could potentially show the cause? That said, I tried the torquing it up and again this eve and the tightness on the end float had swapped sides!

 IMG_2280.jpeg   122.04K   1 downloads
 IMG_2278.jpeg   37.39K   1 downloads  IMG_2279.jpeg   42.08K   1 downloads

Edited by lildeucecoop72, 11 May 2023 - 09:49 PM.

[Chris1275gt]

I’ve no idea on how to rebuild a gear box but your using a steel ruler instead of an engineered straight edge and are presuming the steel ruler is dead straight which it probably isn’t. I have done that and was chasing the error that wasn’t there.

[lildeucecoop72]

I’ve no idea on how to rebuild a gear box but your using a steel ruler instead of an engineered straight edge and are presuming the steel ruler is dead straight which it probably isn’t. I have done that and was chasing the error that wasn’t there.

 

Good point Chris1275gt.

The ruler is new, but as you rightly say, it might not be totally straight, so could be pointless excercise.

After som reasoning, the finger of blame is pointing increasingly towards the thrust face of the box so was interested in seeing if I could check it in some way, but this is exceedingly difficult to do accuratly with normal garage tools. I guess another point is it would depend on outer edges of the box (where the gasket/transfer case mate) also being dead straight.   

[lildeucecoop72]

Ok done some more checks after I bought 2 identical feeler gauges.

Long story short, I did a number of tests, and changed to a green gasket which is slightly thinner than the salmon coloured which got broken in the earlier tests.

I ended up managing to get an average endfloat of just a over 0.004” (0.00431”) This was on the fifth try. The previous test were either too slack with the salmon gasket or too tight with the thinner green gasket when changing out the trust washers. I felt I hit the best I could without major work being done at a machine shop to get it dead straight. I am still not sure why the readings are different either side of the idler, but I guess it could be a combination of factor or it’s always been that way, I just didn’t measure so thoroughly last time.

In the last test got the average by rotating the thrust washer by 90 degrees and taking a measurement with 2 feelers.
The results as seen from inside the box, gasket in place and bolts torqued to 25NM:

0 deg
Left feeler 0.006”
Right feeler 0.004”

Difference between: 0.002"
Average between: 0.005”

90 deg
Left 0.0055”
Right 0.0025”

Difference between: 0.003"
Average between: 0.004”

 

180 deg
Left 0.006”
Right 0.0025”

Difference between: 0.0035"
Average between: 0.00425”

 

270 deg
Left 0.005”
Right 0.003”

Difference between: 0.002"
Average between: 0.004”

 

Totals:

Average difference between: 0,003375 or round to 0.0034"

Total average: 0.0043125” Or to round down, 0.004”

 

This might not be the best way to calculate but I feel that I have done due diligence. This would suggest that the thrust washer is ‘bent’ or has varying thickness. I have not checked it with a micrometer but spinning it and watching bye eye and feel does not suggest so.

Does any one know if the helical side thrust pushes the idler towards the transfer case or the gearbox when running?

Edited by lildeucecoop72, 16 May 2023 - 05:19 AM.

[Spider]

What these variations suggest to me from experience is that at some point, the Idler Gear Bearing has been replaced by heating the case and / or the Flywheel Housing is not aligned to the Gearbox.

Can you kindly through up some photos of the shafts of the Idler Gear ?