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Hi! Sorry bout answering this quite old thread. This is really great topic, and just what I needed, so thats why. I've planned to rebuild as definitive classic 900 gearbox as possible with quite low budget, so I'm going to ask maybe more later. Now there is few questions, which I didn't find answers yet - maybe there is, but I weren't able to find those because my English skills (Finnish is my mother tongue, so), or then there is no answers for those yet.

To the business. Is there anything to find out do a gearbox have chillcast pinion housing, or is only way to find out to take the gearbox of and check? My friend have two cars, MY '84 both, with 5-speed boxes and 8-valve normally aspirated injection engines, so is it possible that I could get those parts from other of those cars?

Other thing I've wondered is about fitting 5-speed parts to 4-speed chillcast gearbox case, that I already have from a Saab 99. I've planned to get MY '91 or younger box to have those sligtly wider gears, which it's told to have. But which years models could possibly fit without modifications to chillcast case? Is it still a reasonable plan to get another box from MY 89-90 and fit that stronger shift fork and maybe rear pinion bearing?

Or is it going to be a real mess, if I try to make four different boxes up to one?:cheesy: I'm not a car mechanic, but few friends of mine are and they will help me, after I've hunt all the parts I need. Problem is to find out what I'm going to need, after that to find those parts is maybe a bit easier here in Finland.
 

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There is no way to know for sure which gearbox will have the chillcast pinion housing but there are some which are more likley to have it. The more likely ones are the ones produced around the mid period 84, 85, 86, 87... I suppose if you got the part number from the chillcast pinion housing shown earlier in this thread you could look on the Saab EPC (electronic parts catalogue) and find out exactly which model years had that kind of pinion housing.

As for fitting stuff together from different boxes, provided that you can measure all the clearances and everything measures correctly, all the right parts are included and the completed box can be turned by hand without any major issues + you can select all the gears and still turn by hand then the box should be working when you install it. Follow the rebuild manual carefully. Bearing tensions need to be set correctly.

Depending on which parts you are trying to install you may find machining work is required to the casing to get the parts to fit.
 

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From what I understand (and mmoe may want to comment on this), 5-speed gearboxes from 85' and 86' cars are most likely to contain a chillcast pinion bearing housing. However, in one of the earlier posts (and referenced in one of my earlier replies), it seems that eeuroparts in the US sells a pinion bearing housing with the same part number as the chillcast housing; I'm not certain if it's the same piece, but it's easy to determine by looking at it (and perhaps someone who is interested might request a better photo of it from eeuroparts).

As for the chillcast rebuild, I've taken an 83' 5-speed box and fitted it into a 99 4-speed chillcast case without any modifications. The biggest thing is you need the transfer case/5th gear housing from the 5-speed fit onto the 4-speed chillcast, everything in the main casing will fit. However, I think this only works for cases before a certain year (89?) after which the pinion bearing housing was enlarged to accommodate a larger pinion bearing on one side and the shifter forks were beefed up. Thus, if you're using parts from later gearboxes, in order to fit a chillcast case you will need to make modifications. Or rather, the reason why gearsets and parts from earlier boxes fit the chillcast case is because their overall fitment remained unchanged since the chillcast case was designed (ie. nothing beefed up, sizewise).

li Arc
 

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To fit '89 and newer gears in to a chillcast, 2 things must happen. First, you need to have clearance machined for the cluster gear. The newer cluster gear is longer due to the addition of an inner race with a "T" shape to it. That must be removed from the case. Then, the pinion housing must be made to fit into the case. This can be a modification to the case by enlarging the hole and lengthening the mounting holes/threads to match the late model cases, or you could have a custom pinion housing made that maintains the older outer diameters and accommodates the larger bearings of the '89+. The advantage of a custom pinion housing is that you could also have it made for the older pinion/ring ratio if desired. There is a larger bearing available that will also work with that older pinion/ring which was never a Saab part, so there is no bearing housing that currently exists which provides the larger bearing on the older pinion/ring. A custom housing obviously allows for that sort of change. The later pinion/ring ratio is 9:35 while the earlier ring/pinion ratio is 9:33. You must just decide what your preference is.

I also believe now that the best approach to building a custom box is to decide what is important to you in terms of how the transmission operates, moreso than just which parts are "stronger". Also, condition of the gears is a bigger factor than their size. IMHO, I don't see a huge problem with using the older gearsets ('88 and earlier) provided that they are in excellent condition. If you bought brand new gears and had them cryotreated and shot-peened, I would imagine they could take a considerable amount of abuse for quite some time in a chillcast build.

As for pinion housings, I find the chillcast variety in '85-'88 models and as far and I know that is all they produced during those years. I've never come across a pinon housing in those years that was anything other than chillcast, but perhaps that's just a U.S. delivery thing if ejenner has seen them over there. Personally, I would have a custom housing made (if you can do it or afford it) to allow for enlarged bearings without modification to the case. I think part of what makes the chillcast strong would be disturbed by enlarging the hole for the later pinion housings.
 

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Ok and thanks for extremely quick answers!

My goal is to build nice street machine gearbox, not a racing one. But it should be able to handle maybe a quarter mile drag or a top speed mile sometimes, without fear of broke it easily, so i think that it should be customized a bit, if my target horsepowers is somewhere between 250 and 300 horsepowers in somewhere future. For now I'll have something like 200hp and a MY '90 stock gearbox, mileage over 300 000 km, so with that box it's not going to be too very smart to get lot more power out of engine.

It sounds like a plan to have older 5-speed gears to my chillcast case, if it's so much easier. Have anyone any idea, how much power and/or torque is that kind of box able to handle? With oil cooler and differential lock, of course, those are next thing to get after I've decided the part set up.
 

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Dragging this one back to the top :)

I've been offered a case from a fairly early 99 - it's an 870352 and it's covered in lovely strengthening ribs and looks the part. Early on in this thread it is mentioned that it is a chillcast but not all pinion bearing housings fit. Can anyone shed any more light on this?
 

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As mentioned in this thread, the drain plug only drains 1/3 or so of the tranny. I'm looking for solution to drain the whole thing without having to take the tranny out.
Put front end on jacks/ramps and remove the back cover plate. Nearly all the oil will come out and you'll get to check/clean the attached magnet and filter cup (if installed). I still remove the drain plug first so removing the back cover isn't quite so messy...

(I think) you would have found this info under the general maintenance forum.
Practice using the search... ;)
 

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Put front end on jacks/ramps and remove the back cover plate. Nearly all the oil will come out and you'll get to check/clean the attached magnet and filter cup (if installed). I still remove the drain plug first so removing the back cover isn't quite so messy...

(I think) you would have found this info under the general maintenance forum.
Practice using the search... ;)
Thanks. My search was not specific enough.
 

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dw about draining the whole thing, its not like you're going to get all the contaminants out.

I have pulled down transmissions with clean oil, but the amount of swarf and crap in the recesses of the gearbox is ridiculous.

The only way to get a worthwhile result from a total fluid change is to strip clean and rebuild the gearbox lol but seriously -

just change the oil and dw about the stuff in the primary case.
 
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