rollerize 904 help

[mopardemon340]

looking at maybe rollerizing my 904. does anyone know what thrust bearings are needed, do you only rollerize the gear set or do you replace all the thrust washers with thrust bearings.
pictures of any machine would done would be helpful to.

thanks

 

[TrailBeast]

looking at maybe rollerizing my 904. does anyone know what thrust bearings are needed, do you only rollerize the gear set or do you replace all the thrust washers with thrust bearings.
pictures of any machine would done would be helpful to.

thanks

The original babbit washers are WAY tougher than Torrington bearings.
That said IIRC they make them for some places in the trans, but not for everywhere there is a washer style.
Only for the front drum to pump stator, one side of the planetaries and reverse drum to case I think.
Been a long time so maybe more now.

 

[fishy68]

I agree with Greg that the factory thrust washers are tougher than torrington's and IMO there isn't that much to gain by rollerizing a 904. If you were only drag racing it and looking for that last .010 in the 1/4 it might be something to consider

 

[Duane]

View attachment 1715082139

looking at maybe rollerizing my 904. does anyone know what thrust bearings are needed, do you only rollerize the gear set or do you replace all the thrust washers with thrust bearings.
pictures of any machine would done would be helpful to.

Here is a parts list. I have done this and there are a slew of rollerized pics in my profile that you can view. I also just finished doing an improved version of my low gear set a couple weeks ago.
The bearings that I use are not the ones in the parts list but they are similar. I used ones from GM 465 Le found in early 2000 Gm pickup trucks. You can get them right from the dealership.
It is a lot of work to do.

 

[Duane]

I agree with Greg that the factory thrust washers are tougher than torrington's and IMO there isn't that much to gain by rollerizing a 904. If you were only drag racing it and looking for that last .010 in the 1/4 it might be something to consider

Almost all modern transmissions from the big 3 used Torrington bearings for many years now. The overdrive in all the Chrysler truck use torringtons to handle the pressure of that 800 pound spring.
They live in a diesel application, the thrust washers do not Imho

 

[TrailBeast]

Almost all modern transmissions from the big 3 used Torrington bearings for many years now. The overdrive in all the Chrysler truck use torringtons to handle the pressure of that 800 pound spring.
They live in a diesel application, the thrust washers do not Imho

Don't forget converters.
I would agree that the bearing would last better under a constant high pressure load.
I have also seen the bearings make a huge mess when they let go.
Don't get me wrong, as I didn't mean they are no use, but only that under the intended use for the OP they are probably not worth the effort.

 

[oldkimmer]

Ya they make a nasty mess when they let go. My race duster uses just the tried and true thrust washers. Kim..

 

[Duane]

Don't forget converters.
I would agree that the bearing would last better under a constant high pressure load.
I have also seen the bearings make a huge mess when they let go.
Don't get me wrong, as I didn't mean they are no use, but only that under the intended use for the OP they are probably not worth the effort.

Agree totally. It is a lot of work to rollerized and I have seen no evidence of any performance gain. Yes I suppose that needle bearings everywhere in the case would not be good. All I was saying is that they do work and can take way more load than a thrust washer, and are reasonably reliable, otherwise the oem,s would not use them. One thing that is very importance when rollerizing is to keep the end play extremely close. A sloppy fit and they can disassemble. The picture I posted, it took me hours of trial and error to get the gear assembly to run true in the chuck and 20 minutes to machine. That's for one bearing. Lol
But it cost me nothing but my time and a set of bearings and I know how to do it so I did.

 

[mopardemon340]

thanks guys.. ill keep with the standard thrust washers.. can you tell me how to tell if i have low or high gear sets?

 

[AJ/FormS]

Is the trans currently installed and driveable?Then it is a simple as measuring the 1-2 shift rpm drop after TC lock up is achieved.
The regular 904 has an rpm drop to 59%, while the low-gear units have a drop to 56%. So drive to 4000 rpm under power in first gear and make note of the exact rpm. Then stuff it into second , slow down to maybe 10 mph under the noted mph, and accelerate briskly back up thru that rpm, noting the exact rpm. Then take the second rpm divide by 4000 and that will equal the rpm split.
For instance ; the 59% will drop to 2350, while the 56% will drop to 2240.
As you can see; accuracy in the method is paramount, cuz there's only 110 rpm difference. If your does not lock up until some higher than 2350, then you may have to choose a higher shift rpm.
Another method involves even more math, and is probably a little less accurate.

If the trans is on the bench
the easiest is to grab the transmission number off the panrail, and do a look-up. Also a lot of them have a great big ol' identifier cast on top of the bellhousing; I've seen A904, and A998. I can't say all have the identifier, cuz IDK.
All 904s were 2.45-1.45-1.00
All A998s are 2.74-1.54-1.00........I think all
All A999s are as 998s except they are lock-ups...............I have been told.
The few that I have come across all have followed this pattern.
Each has it's preferred useage.

If the trans is torn down then it's obvious by looking at the sun-gear. The 904 sungear is the same from top to bottom, while the low-gear sun has two different ratios , and looks stepped.

 

[fishy68]

Another way to tell is by the gear train layout. Here are pictures. The first is the standard ratio sun gear layout and the second shows the low/wide ratio sun gear layout. The main difference you'll see is the sun gear. On a std ratio trans the sun gear has equal splines on both sides. On a wide ratio trans it has an unequal spline count

 

[Bakerlite]

Don't forget converters.
I would agree that the bearing would last better under a constant high pressure load.

As long as they can get a good supply oil to remove heat, otherwise they will cook and fail.

 

[B3422w5]

Few years back i replaced a pretty much stock rebuild 727 that finally gave out behind a relatively heavy high 9 sec car, with a fully rollerized 727 with aluminum drum.
This was built at a super highly reputable shop who specialized in stock/ super stock trannies.

End result. I saw zero on my time slips on a very well sorted out car.

 

[mopardemon340]

thanks everyone for all the help