[Dellanator]

Hey all

I've just acquired a new project car and I'm looking for experienced advice if anyone could help. I have basic vehicle maintenance experience (oil changes, manifold/turbo swaps etc - nuts and bolts type stuff but not internals) and am hoping to learn more with this project (so apologies for the noob questions).

It's an 89 Sierra with a Vitara motor that runs great. The problem is, the drive shaft snapped and teared up the cockpit floor while the old owner was driving. The guy who towed it for him said it'd need a new selector and front drive shaft.

I've since got it home, removed the driveshaft and can see some of the damage done to the selector now that it's exposed (see photos). You can also see where it's snapped the joint on the gearbox end.

My questions are;

Can the tube/centre bearing that goes into the transmission from the drive shaft be removed and the new (complete) drive shaft inserted?
If yes, is it a DIY job (any how-to links appreciated) or does it require a mechanic?

At the moment I'm thinking it'd be easier to replace the whole gearbox and drive shaft. It may be better in the long run to upgrade the box also (suggestions welcome).
Can anyone tell from the photos if that's a vitara or sierra box?

Also, would a vitara box/ drive shaft fit directly into the Sierra or would it need mods?

thanks in advance

[greavesyzook]

Thats a throw away job lol yes it's a stock sierra 5 speed box.... Your best bet put another one back in or a aw4 auto but will need tunnel mod ect...

[Dellanator]

Cheers Greavesy, much appreciated... couple of other questions for you or anyone else if you dont mind...

- Could the Vitara v6 engine working with the Sierra box have caused the drive shaft failure? As in, the engine being too powerful for the box? The seller told me that it had been in there for a year or so with no issues up to the big bang point

- If be above could be the case, is it possible/ what would roughly be involved in fitting a Vitara gearbox/ drive shaft to the Sierra- other running gear that would need changing/ modifying chasis/ mounts etc?

cheers mate, any help at all would be awesome

[Dellanator]

Cheers for the info Greavsey, much appreciated.

A couple of other questions for yourself or anyone else that might be able to help if you have the knowledge/ experience:

- Could the Vitara v6 engine working with the Sierra box have caused the drive shaft failure? As in, the engine being too powerful for the box? The seller told me that it had been in there for a year or so with no issues up to the big bang point

- If the V6 could have caused it, is it possible/ what would roughly be involved in fitting a Vitara gearbox/ drive shaft to the Sierra- other running gear that would need changing/ modifying chassis/ mounts etc? Or is there other, simpler mods (different clutch etc) that could be done to strengthen up the box and avoid another shaft failure?

cheers!

[bumstein]

Yeah you could replace the extension housing and output shaft, but I can’t see why you would. Should be able to find another 1.3 gearbox easy enough and hang onto the old one for spare bits.

While you’ve got the gearbox off, replace the clutch too. For the cost of a new clutch it’s easy to do while it’s all apart and piece of mind iMO.

Do the swap yourself, if you can undo and tighter nuts and bolts you’ll well equipped to change a gearbox

[MrRocky]

New box, allow half a day. May as well do the clutch, rear main, spigot/thrust bearings and gbox input shaft seal while your at it and not have to worry about it again for a few years if you intend on keeping the car

[fordem]

Dellanator wrote:

Could the Vitara V6 engine working with the Sierra box have caused the drive shaft failure?

I don't mean to be insulting, but I would not have thought you could shoe horn an H20a V6 into a Sierra or mate it to a Sierra transmission, are you sure that's a V6 in there?

[Gwagensteve]

Dellanator, from what I can see in the photographs, you don't have a V6 in the car. The V6 is extremely bulky and will require lots of custom fabrication. I can see the exhaust on the LHS of the engine (where it is on the 4 cylinder 1.6 car) and no evidence of exhaust on the RHS of the car. Also, I think it would be very difficult to adapt the Sierra transmission to the H20 V6.

Next, The gearbox DID NOT FAIL. The shift housing was damaged when the universal joint failed on the jackshaft adjacent to the gearbox. When this uni fails, the jackshaft flails around and causes a lot of damage. The bearing surfaces of the uni are visibly heat damaged. -Note how they are blue and flaky looking.

Fitting a Vitara gearbox is possible, although quite a lot of work. However, vitaras, including the V6, use the same size universal joint as the Sierra.

Did the vitara engine cause the failure? No. Uni's are wear items and the unis on the jackshaft see the highest velocity. It wouldn't surprise me if that uni was in the car from manufacture in 1989.

There can be another contributing factor - The jackshaft is very short and this makes the unis very sensitive to angle. There may be bends in the transfer arms, which are pretty common on cars with more powerful engines. Bent transfer arms change the uni angles on the jackshaft and this leads to rapid or accelerated failure.

[Gwagensteve]

Oh, I see I was a little sidetracked by some of the other replies - I'll try and answer your questions in more detail.

The Vitara uses a mated gearbox and transfer case. Whilst it is an upgrade, the vitara transfer case has to be removed, the tunnel enlarged, and the jackshaft shortened.

I would replace the transmission with another sierra transmission, or, alternatively, just swap the tailshaft/ shift housing from another transmission, and replace the jackshaft.