M5R2 Input Shaft

Hock

Hock

Registered User
How much play should the input shaft have for our 5 speeds?

I have 2 of them sitting and they are about the same which seems excessive to me.
 
Hock said:
How much play should the input shaft have for our 5 speeds?

I have 2 of them sitting and they are about the same which seems excessive to me.
Click to expand...

Should be just barely perceptible. I set mine at about .001". Factory spec is .002" I think.
 
Ok.

Now how can I go buy finding out what is wrong and fixing it without getting to far into the trans?
 
Hock said:
Ok.

Now how can I go buy finding out what is wrong and fixing it without getting to far into the trans?
Click to expand...

Simple. Remove the front cover and measure the clearance between the bearing and the cover. You'll need a depth micrometer to get an accurate measurement. Then compare that to the factory installed shim. Using shimstock ( I get .002", .005" and .010" from any machine shop) and cut out some shims. You can also buy a shim kit from Southern Gear or Ford may still have some shims available but you have to know the part numbers and they may be discontinued. Cutting them out is easy. I've seen some trannies with as much as .015" clearance. When you are done the input shaft should be *almost* dead tight. Just a slight bit of movement lets you know you have it right.
 
XR7 Dave said:
Simple. Remove the front cover and measure the clearance between the bearing and the cover. You'll need a depth micrometer to get an accurate measurement. Then compare that to the factory installed shim. Using shimstock ( I get .002", .005" and .010" from any machine shop) and cut out some shims. You can also buy a shim kit from Southern Gear or Ford may still have some shims available but you have to know the part numbers and they may be discontinued. Cutting them out is easy. I've seen some trannies with as much as .015" clearance. When you are done the input shaft should be *almost* dead tight. Just a slight bit of movement lets you know you have it right.
Click to expand...

Dave, my manual says to seat the race with a drift to take out any play, measure the difference, and then add .002"-.006" to determine shim thickness. It sound like the bearings needs to be slightly loaded....is this right? It makes sense due to the race possibly spinning in the bore.

John
 
keisers1001 said:
Dave, my manual says to seat the race with a drift to take out any play, measure the difference, and then add .002"-.006" to determine shim thickness. It sound like the bearings needs to be slightly loaded....is this right? It makes sense due to the race possibly spinning in the bore.

John
Click to expand...
No, the bearings need clearance. If you load the bearings you will create heat. The shaft is long and will grow under load (heat) so you want some clearance. .002" is *just* perceptible wiggle in the shaft once you have it back together. If you pre-load the bearings you will create heat and friction in the bearings themselves.

The races fit loosely into the case, so if you preload the bearing you will CAUSE the races to spin. This would be bad.
 
XR7 Dave said:
No, the bearings need clearance. If you load the bearings you will create heat. The shaft is long and will grow under load (heat) so you want some clearance. .002" is *just* perceptible wiggle in the shaft once you have it back together. If you pre-load the bearings you will create heat and friction in the bearings themselves.

The races fit loosely into the case, so if you preload the bearing you will CAUSE the races to spin. This would be bad.
Click to expand...
That makes sense, but I would think that the load would not increase from heat due to the fact that the housing will expand at a greater rate 2x (aluminum). I do agree with you on the preload...seems that the extra thickness (.006" potentially) added can be dangerous if the play is taken out from the initial measurements.

I was trying to figure out why the plate is worn so bad on the output shaft side (.015 on my tranny)...could it be from the pounding of the slider rings into the gears??

By the way, what friction modifier do you use?
 
keisers1001 said:
That makes sense, but I would think that the load would not increase from heat due to the fact that the housing will expand at a greater rate 2x (aluminum). I do agree with you on the preload...seems that the extra thickness (.006" potentially) added can be dangerous if the play is taken out from the initial measurements.

I was trying to figure out why the plate is worn so bad on the output shaft side (.015 on my tranny)...could it be from the pounding of the slider rings into the gears??

By the way, what friction modifier do you use?
Click to expand...

You may be right about the case expanding, but my guess was based on the idea that the shaft gets much hotter than the case does. The shaft on my truck 5spd got so hot it cooked the thrust bearing during a long 2nd gear haul up a hill at WOT. There is actually very little cooling that makes it to the shaft itself as it is completely covered with gears it's full length, not to mention it has wide roller bearings almost its full length as well.
 
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