Crash box’s - Lined or Un-lined

Driveline (including transmissions, differentials, tailshafts) discussion.

Crash box’s - Lined or Un-lined

by NSWEH225M » Thu Oct 03, 2019 9:25 am

Can anyone tell me how to tell the difference between 5 bolts crash boxes, specifically wether it’s a lined or non lined gearbox ?

From the research I’ve done so far, it looks like that the only external indicator is that there’s a difference in input shafts.

Also it looks like there are different version of the side plates / side covers. Can anyone shed any light on this ?
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Re: Crash box’s - Lined or Un-lined

by EJ_VE_EH » Thu Oct 03, 2019 7:40 pm

The early EH crash boxes were basically the same as EJ crashboxes, and deemed unsuitable for the 179. These are the 4-bolt ones.
So only manuals were available with the 149.
Later they developed the stronger 5-bolt crashbox which then allowed both the 149 and 179 to be ordered as manual.

They are very easy to distinguish. The 5 bolt one has a deeper cutout where the slave cylinder goes past.
The 4 bolt slave cylinder has attachment bolts inline with the cylinder (i.e. one above and one below the cylinder).
The 5-bolt slave cylinder has offset attachment bolts in relation to the cylinder.
This is why you get 2 different bellhousing attachment gaskets in a gasket set.
5-bolt Crashbox
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The later 5-bolt crashbox gears (HD?-HK)had lines on the gears themselves, indicating they shouldn't be interchanged with the unmarked ones.
Regarding the cover plate, I've seen a few versions. I think they evolved over time.

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Re: Crash box’s - Lined or Un-lined

by NSWEH225M » Fri Oct 04, 2019 9:57 am

Thanks Andrew,

When I rebuilt my gearbox I didn’t know there was such a thing as lined or in-lined, so it’s now in the car and I have no idea what type it is. All I know is that it’s noisy and jumps out of 3rd every now and again.

The 2 other spare gearboxes I have are both lined, so the question is which gearbox of the 3 should I rebuild ? Looks like I might be pulling the gearbox out of the car over the long weekend.

On line I found a picture of 2 input shafts, one lined and the other non-lined. I’m fast getting a crash box education;<)
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Re: Crash box’s - Lined or Un-lined

by EJ_VE_EH » Fri Oct 04, 2019 1:11 pm

I had no idea about the lined/unlined gears either, the first time I rebuilt one. Don't know if it was the problem.......I just removed it in disgust and put another one in.
This diagram may help. It shows the drive pathway in 3rd gear (I think I pinched it from Harv's guide):

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The problem would be in the red area somewhere I suppose......or is it noisy in all gears ?
Popping out of 3rd would be the 2nd/3rd speed clutch sliding back for whatever reason.
I know the 2nd/3rd speed clutch and main shaft came as a matched pair when a spare was needed. Try to keep them together,
Good luck!
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Re: Crash box’s - Lined or Un-lined

by Harv » Fri Oct 04, 2019 2:53 pm

Yep, that's a drawing from my Crashbox Guide. Holden three-speed manual transmissions were of three main types:
a) The grey motor crashbox, used from FX through EK Holdens (the subject of this document – see upper image to the right). The grey motor crashbox has a bottom transmission cover (sump) and integral casing/bellhousing. The gearbox had synchromesh on second and third gears only,
b) The red motor crashbox, used from EJ through HK Holdens (see lower image to the right). Like it’s predecessor, the red motor crashbox still had synchromesh on second and third gears only, with the internal gear and shaft layout and operation very similar to the grey motor crashbox. However, the gear selector process was changed significantly, as was the construction – red motor crashboxes have a side transmission cover and separate casing/bellhousings, and
c) The Aussie three-speed, used from HK through WB Holdens as well as LC-LX Toranas. The external construction of the Aussie three-speed gearbox is similar to the red motor crashbox, having a side transmission cover and separate casing/bellhousing. However, the Aussie three-speed was fitted with synchromesh on first, second and third gears (often referred to as an all-synchro box), and the gear selector process was changed again.
The Guide was written for the grey motor crashies.

red vs grey.png
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There are a couple of things that can make them jump out of third:
a) Gearshift linkage is not adjusted correctly. Adjust gearshift linkage (selector rod and control rod adjustment).
b) Shifter lock balls do not have full engagement in the notches of the shifter shaft.Using a 5/16” allen key, remove the offending shifter shaft lock spring and ball lock screw (hint: first and reverse is on the passenger side of the car, and second and third is on the driver’s side). Pick the spring and ball out with a “magnet on a stick” tool. Check that the spring free length is approximately 11/8”. Clean up the spring and ball in some kerosene, and use a pipe cleaner to clean any gunk out of the channel in the gearbox casing. Reassemble. If slop is still present, it may be necessary to swap for another spring, or to use a collet/stack of washers on top of the spring.
c) Misalignment between the gearbox bellhousing and the engine crankcase. Remove gearbox and examine the locating dowels in the end of the crankcase. The dowel pins should stick out enough to engage by 5/16” in the gearbox. Ensure gearbox mounting bolts are tightened in a cross-fashion.
d) Bearings or bushings are loose, main shaft sliding sleeve is loose, worn teeth on mating gears.Remove the gearbox from the vehicle and disassemble. Replace the defective parts (replacements can be gotten from a 2nd hand box).

Or alternatively:
e) Handbag missing from shift lever. Replace handbag. Male drivers may not be comfortable driving with a handbag in place with no female passenger. If so, replace handbag with Occy strap. :lol:

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Re: Crash box’s - Lined or Un-lined

by NSWEH225M » Tue Oct 08, 2019 9:00 am

Thanks Harv.

Any ideas what causes the gearbox to be noisy under load (when in top gear) and then the noise goes away when you de-accelerate ?

If all the bearings are new, it must be something to do with worn parts, the cluster, input shaft, synchro hub, first / reverse slider ?
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