Setting bearing preloads

[bwhite]

Ive changed my shift forks and wanted to set shaft preloads. I used the fsm and it says to use .06 solder which I got and measured with but the center diff and the input shaft are not crushing the solder at all. Should I just use the larger 3/32 solder and remeasure? The intermediate shaft shim is. 038 and the solder measurement came up with .042. Does that mean I need a .012 thicker shim to get my .008 of preload?

[turboglenn]

i USED 3/32 AND .062 AND THEY both gave about the same reading but the rosin core lead solder (soft stuff) for plumbing wasthe most consistant, and gavethe best results,

you add to the solder to get new shim size, so with .042 and wanting to shim .008 you need a shim that's .050" thick, I have taken apart a lot of trannies lately and found that there's a lot of shims in bearings that are different thicknesses and im so damn poor that i've had to take and cut them and bend themsmaller or open up and silver solder in an extension from another one the same size instead of buying them all that i need, good thing too since i went through two trannies in under a month

[bwhite]

So I remeasured with the 3/32 and got some better readings but the input shaft doesnt seem right. My original shim was .040, my solder measures .057. So even with the thickest shim I found its still only at .0005 preload. Does that seem right or ok preload? The way I see it is if I had .017 in of endplay, thats within factory spec so the bearings cant be bad. Is there different shims for running that high of preload?

[turboglenn]

No, tha'ts not right i'd be willing to bet from what i've read on here of tim giving advice and similar results myself

Here's afew thigns that i found REALLY matter..get SOFT 3/32 solder, cut the pieces SHORT like only 10mm and place them EXACTLY where the book says/points with the lines in the manual... make sure the bottom of mid case is tight to bell housing, torque it all with the rear cover on (some people talk of leaving it off, i don't have luck like that)

I check each one i have done 4-5 times between both solders.. worsst case put solder on one shaft at a time so there's not a bunch taking the load.. i have seen with used cases and new bearings readings as follows, input is usually in the mid .040's like .043. 046. intermediate is about the same and the center diff is usually around .051 -.053 I had to make customshims from shim stock i have formachining to go under the input shaft one to get it right at .007" preload, i put my int. shaft at .007 -.008, and the CD at .060 shim which is about .007... That's tighter than the first build but although i coudln't turn the input by hand with it in gear, the trans is awesome now that the cluch it broken in

Also, try putting the solder in and leaving it for an hour or 35-40 minutes, , and remember get the soft plumbers stuff, cut pieces SHORT (less area to absorb the crush load ) and tighten everthing to spec and wait, or as i said do one shaft at a time, shim each one you do as you prepare the next one so it gives accurate account of what the trans wil be like assem,bled (my own thoughts there)

But mine clicks into 2md and third when cold at low RPM, higher irev easier it shifts, then once warm no clicking and still shifts great at over 8k RPM when i lost traction playing in a wet parking lot

Sorry so long to reply, my OS registry got f**ked yesterday and i had to format and boot up a second SATA drive into a dual OS to be able to save much of my needed stuff, just finihed tonight

[JackM]

Yes, your input measurements are common for a trans that has been untouched. 99% of the time, we have to add a .010" thicker shim in order for the input shaft to be snug enough. Depending on the year of the unit, some are worse than others.

I wouldn't look at it as a problem. Due to the fact that many DSM trannies have the input shaft way too loose, your .0005" preload should be fine for the average car. If you are going to run a lot of power, I would try to tighten it up a bit more, though.

Another option is to replace the input shaft end bearing at the bell-housing side of the case. Mits has a new revision of that bearing which helps move the shaft up a bit to help counter the loose preloads.

Keeping the input shaft loose allows for faster and a better feel when down-shifting. So for the average street car with 16G power, keeping it a little loose so as to allow for better shifting might be worth it. Too tight and it can start to feel a bit notchy if you road race the car.

Good luck!

Jack

Originally Posted by bwhite

So I remeasured with the 3/32 and got some better readings but the input shaft doesnt seem right. My original shim was .040, my solder measures .057. So even with the thickest shim I found its still only at .0005 preload. Does that seem right or ok preload? The way I see it is if I had .017 in of endplay, thats within factory spec so the bearings cant be bad. Is there different shims for running that high of preload?

[turboglenn]

While i won't dissagree with what you're saying Jack, becuase you've build more than i have in trannies.. there's a thread titled "shimming gurus' needed) on page 2 or 3 in this section where some one was getting large measures like this, and i wasgetting them too until using the proper solder and technique of making sure i wasn't using too long of pieces since it spreads load just like a full face clutch meaning the force won't crush it all as far as if shorter peices were used, I was just saying double check because i got those readings, then did it right and go measure that were in the "normal range" but then again i put new bearings on both input and intermediate shaftts when i built mine, if he has old bearings being re-used that might be a real measurement and not an errrorbut it's easy to make an error is all i was getting at

[bwhite]

Well I remeasured again using 3/32 on the center diff and the .062 on the input and intermediate shafts. I repeated that three times in a row and came up with .051 on the input, .039 on the intermediate shaft and .057 on the center diff. This is a 92 trans with the early fork design. I think my main problem was that when setting the solder in I was setting to far towards the inside and the bearing race was smashing the solder into a triangle. My factory shims were input shaft-.040, intermediate shaft-.038, and center diff-.055. Now hows that sound?

[twicks69]

Sounds way better. Now get the proper shim for your desired use of the transmission. I still put around 0.005"-0.007" preload on drag racing transmissions, and around 0.003" preload on street car daily driver transmissions.

It still sounds like worn tapered roller bearings that should be replaced, but here are the input shaft shim values and part numbers for reference if you are intending on simply reusing your current parts.

Part Description Part Number ID Number Thickness (in)
Shim - Input Shaft MD727658 56 0.0220
Shim - Input Shaft MD727659 65 0.0256
Shim - Input Shaft MD727660 74 0.0291
Shim - Input Shaft MD727661 80 0.0315
Shim - Input Shaft MD720937 83 0.0327
Shim - Input Shaft MD720938 86 0.0338
Shim - Input Shaft MD720939 89 0.0350
Shim - Input Shaft MD720940 92 0.0362
Shim - Input Shaft MD720941 95 0.0374
Shim - Input Shaft MD720942 98 0.0386
Shim - Input Shaft MD720943 1 0.0398
Shim - Input Shaft MD720944 4 0.0409
Shim - Input Shaft MD720945 7 0.0421
Shim - Input Shaft MD710454 J 0.0433
Shim - Input Shaft MD700270 D 0.0445
Shim - Input Shaft MD710455 K 0.0457
Shim - Input Shaft MD710456 L 0.0468
Shim - Input Shaft MD700271 G 0.0480
Shim - Input Shaft MD710457 M 0.0492
Shim - Input Shaft MD710458 N 0.0504
Shim - Input Shaft MD706574 E 0.0516
Shim - Input Shaft MD710459 O 0.0527
Shim - Input Shaft MD710460 P 0.0539
Shim - Input Shaft MD706573 - 0.0551
Shim - Input Shaft MD710461 Q 0.0563
Shim - Input Shaft MD710462 R 0.0575


You can always stack shims to get the desired preload you want.

[bwhite]

Thank you. I used your list from another post you made. Thanks again.