Thread: lt95 rebuild bearing preload

G'day John, layshaft bearing preload is important and is adjusted by the shim sandwiched in between the front bearing race and the oil pump housing on the front of the gearbox. When rebuilding a box use the shim that came out of it and then check the preload before you install the mainshaft. This must be done with the gaskets in place otherwise a different preload will be obtained once you add the gaskets. Often times you will find that you don't have to adjust it and the original shim is still fine. So basically you install the new bearings and races (make sure they are seated fully and oiled). Install the layshaft in the box. Having the box seated upright on the transfer case is handy when you are doing this. Put the new gasket on the front of the box, install the sandwich plate with the shim behind the front bearing race then the oil pump hosing gasket and housing, torque the bolts up to specifications and then check the rolling resistance of the layshaft with a spring balance. To do this you roll some strong string around the layshaft and attach to the spring balance. The front section of the top of the box is the easiest place to roll the string around the layshaft. You need a rolling resistance of 6-8 lbf. If it is not within specs change shims until you get it right. Have fun

thanks brian i have installed the layshaft fitted the largest shim available 2.55mm and only have 1-2 lb preload

Originally Posted by John Ellis

thanks brian i have installed the layshaft fitted the largest shim available 2.55mm and only have 1-2 lb preload

Are you using a genuine gasket set?. Some aftermarket ones I have seen have thicker gaskets that require thicker shims. One way to remedy this is to fit a shim behind the rear bearing race or get a genuine gasket kit (part number 606754). Was the 2.55mm shim the one that came out of it?

when i fitted new bearings and gasgets and fitted the original shim i ended up with 10thou endfloat gasgets and parts came from 4 wheel drives melbourne

Originally Posted by John Ellis

when i fitted new bearings and gasgets and fitted the original shim i ended up with 10thou endfloat gasgets and parts came from 4 wheel drives melbourne

I would imagine it's an aftermarket gasket set which may be the problem but he bearings could be different also. Are they Timken or another brand?

brian i think your right in an effort to save money ive created the problem thebearings are timken but thegasgets aftermarket i have been trying combinations of shims and have just about solved the problem i cut a shim out of .152mm shim material added a 2.39mm ? shim and have a scale pull of around 7lb what a relief thankyou for your interest and advice hopefully the rest of the rebuild will be trouble free john.

Had the same problem with the aftermarket gasket set when I did mine.
You'll probably have the same issue with the output housing and centre diff preload.
I bought genuine for the front gasket, but cut my own from gasket paper for the output one.

Steve