MS6 AWD trans bearings / preload question

[Boltz]

I have my transmission out replacing the clutch, and standard inspection I check the input shaft for play and feel for rotation issues. I find that there is (Aprox 8 to 10 thou) play which to me most trans shouldn't have any because of taper bearing preloads on both ends of the shaft. However from reading over the trans manual The input shaft has a roller bearing at the bell housing side and a ball bearing at the driver axle side. The instructions only talk about preloads on the differential taper bearings and secondary shaft (No2)

So what I am looking for an answer to is if this play is normal or not. I haven't disassembled the trans to know fully how it works. I dont want to do unnecessary work or parts if this is normal.

I will be having the Bulk buy shifting forks installed, but i dont want to set bearings.

Thanks

[93GTS]

I can't say for our trans, but other transmissions (T5, G5M, etc) have play when they have been used at all. The RWD T5 input shaft can literally flop from side-to-side as well as in and out on some of the transmissions I've seen last 100,000 miles. Of the FWD G5M's that I've torn apart, all of them have at least 1 shim... and all of them have had shaft play. I have a brand spanking new one on a pallet in my garage right now that has shaft play.

[06Speed6]

Its pretty normal, if the trans was making noise, you can check the ball bearings by hand and replace any that dont turn smoothly.

[Boltz]

Thanks. I was prety upset when I found it. I am used to all shafts having taper bearings shimmed to no play. As far as i know there are no issues internally

[93GTS]

If you're concerned, a shop probably wouldn't charge much to strip off gears and change the bearing.

If you're doing it yourself, you'll need bearing/gear separators and a lightweight (cheap 10-12 ton) press with a tall stand (36") as well as a few punches, shop manual (clearances), a dial indicator, and hand tools.

If it is any consolation, those tapered bearings are generally the same part number as wheel bearings on other vehicles... so they are tough.

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[06Speed6]

Pfft I swapped bearings on my trans with a bearing seperator, a small sledgehammer, and a 6" section of pipe lol. Took like 20mins

Ive never opened a ms3/6 trans that didnt have bad ball bearings. They arent made to handle thrust loading so they tend to have short lives.

[93GTS]

On some trans, the input shaft bearing is first, on others you have to strip all of the gears off of the shaft. Thw only reason for tall stand on press would be long shafts like a rwd t5 or t56

Was it inly the input shaft bearing or did you do diff bearing and others?

If op os worried about pre-load theb dial indicator and base aren't optional tools either. There's probably shim-selection sst to help.

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[06Speed6]

The diff has tapered roller bearings that are just about indestructible. I just swapped a roller bearing on the input shaft and three ball bearings. No shims on those shafts.

EDIT: I swapped a gear and input shafts too because mine was trashed and the gear was rocking on the shaft.

[93GTS]

Yeah, that was kind of what I was trying to get across in my first response. Tolerances aren't usually as tight as the shop manual makes them out to be.

I swapped several front cases off a enough four cylinder g5m transmissions to fit kl engines now to know that if preload was that important I'd have had a failure. Lol, with them, the diff usually explodes.

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[93GTS]

Originally Posted by 06Speed6 The diff has tapered roller bearings that are just about indestructible. I just swapped a roller bearing on the input shaft and three ball bearings. No shims on those shafts. EDIT: I swapped a gear and input shafts too because mine was trashed and the gear was rocking on the shaft.

Didn't see your edit. Were you able to strip the gears off if the input shaft with just hand gear puller? Usually, press-fit is pretty snug!

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[06Speed6]

I just put the separator under the gear, hung the separator in my bench vice, and hit (I think) a 1/2" socket extension on the shaft with a small sledgehammer. The bearings and gears are all press fit. The c-clip on the ends of the shafts is just for decoration I think.

Initially I used a separator with a 3 arm pulley puller and that was fine for the bearings but it didnt have enough reach for the gears

[Boltz]

Originally Posted by 06Speed6 Pfft I swapped bearings on my trans with a bearing seperator, a small sledgehammer, and a 6" section of pipe lol. Took like 20mins Ive never opened a ms3/6 trans that didnt have bad ball bearings. They arent made to handle thrust loading so they tend to have short lives.

Ugh... so these trans bearings are problematic with our cars then? When it is appart do you recommend replacing the ball bearings any way then?

I know it would be hard to shim all the shafts but it really makes sense to have put taper bearings on them all.

[06Speed6]

Yeah tapered roller bearings would be way better.

Those ball bearings are ~$50/ea so they add up fast. I just replaced two of them along with the roller bearing on the input shaft. Ide just replace bearings that are rough when you spin them.

[93GTS]

Is there not a timken or skf interchange# for the roller bearing yet? If you post up the mazda # I might be able to find it today if it exists.

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[Boltz]

Bearings are easily cross referenced by style ID and OD. I dont know them though.

[93GTS]

I have a friend who works for a bearing distributor. That's exactly what I was going to do.

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