218 to 242 swap

[hummer4x4guy]

Can someone tell me what is a good price for a new 242 tcase and if the gearing ratio is a higher or lower gear then a 218 ie: higher speeds lower rpms.

Trying to figure out if it would be worth it to gain a lil speed
Thanks

[Action]

i think 500 - 600 is fair price for new one.

i dont know about the gearing, though.

Jason

[dunsbr]

Hi Joel,

I'm more around $450 for the price. (I've bought 3 for this price)
As i understand it, there is no difference in the Hor HL gearing at all between a 218 and 242.
So you will get no direct benefit from the swap.

However, the internal differential design in the 242 is much more sophisticated than the 218's and it is much more suited to sustained high speed driving on hard surfaces.
So in that reagrd, the swap is worthwhile.
Also, the 242 is smaller and lighter giving more room under the truck to work.

Cheers

[dunsbr]

Oops, I re read your post, my T/cases were rebuilt for $450 not new...

Cheers

[hummer4x4guy]

OK Brad thanks for that info. That would make it worth while to try and get one then. I appreciate the help!
Joel

[hummer4x4guy]

OK I won the tcase. Do I also need to change out the drive shafts or the driveshaft ends?
Joel

[Action]

the rear 242 driveshaft slips into the back of the T/C.

the 218 uses a cross there.

[dilvoy]

Don't you have a turbo 400 in your truck Joel? If so, just make shure the 242 mates up properly. I don't think you will have a problem with the mounting bolts fitting into the adaptor, but the T case input shafts may be different so as to cause an interfereance or maybe they are different but still work properly.

[hummer4x4guy]

George
Yeah I have the turbo 400 (a very misleading name for a transmission)
As Jason said I thought that there was a change in drive shaft hookup..just was not sure where that was. Will I simply need to buy a different rear drive shaft or is there an adapter that can be put on?
Joel

[dilvoy]

You'll have to make a custom driveshaft, because the turbo 400 is shorter than the 4l80E. If you have converted to the dual parking brakes on the service brakes, you can get the yoke that uses the larger U joint for the pinion on the Diff, which will match the size of the U joint that fits the yoke that slips into the T Case. If you still have the driveshaft parking brake or still have the special yoke for it on the diff, you'll need to have the driveshaft shop re use the rear portion of the driveshaft. It will then be big u jount in front and small at the rear or combo u joint in the rear. For the front driveshaft, a shorter one will be needed for the rear section and a combination U joint or if you are luckey, you can install the front output yoke from the 218 on the 242 and you can have all small u joints up front.

[Ozhumvee]

If you go to humvee.net and have a look in the information database under transmissions you will find a word document detailing the changes when fitting a 242 in place of a 218. That doc also included fitting a 4L80E but the driveshaft stuff as dilvoy explained will still need sorting out.
Basically you will need the later model driveshaft rejigged to fit the increased length between the rear diff and the transfer (a 4 speed tranny is longer).
Depending on whether the humvee has the tailshaft handbrake or uses the later rear caliper brakes you will have to change the pinion flange on the rear diff.
Alternatively look around for the part number for the rear tailshaft fitted to those humvees that came out with a turbo 400 and a 242 transfer case with rear caliper handbrake, they were around in the early 90's. One of the Aussie shelter carriers had that setup from the factory.
The front output flange on the 218 will need to be fitted to the front output on the 242 to hook up to the rear uni on the front shaft. I did that with mine.

[hummer4x4guy]

Oh this will be fun!
Luckily I do have the upgraded parking brake system so thats not a problem. I will check out the info on humvee.net once I get some spare time.
I appreciate the info fellas.
Joel

[hummer4x4guy]

I recieved email today that the driveshafts are on their way that go with the 242 tcase in a humvee. As soon as I get photos of them I will post some side by side photos of the old and new and let you all know if in fact these will work properly without more changes needed.
Joel

[hummer4x4guy]

Driveshafts arrived today. Looking GOOD and just in time I am getting some major popping (more major then usual) when I put the truck into gear.

[hummer4x4guy]

Today I got the front driveshaft out and the rear as well but that was out last week.
I have all but one nut taken off holding the tcase onto the transmission adapter. This nut wants to stay on! I have map gas heated it I have ground it down I have then reheated it and hit it as best I could with a chisel to try and break the nut in half. Visegrips wont move it. There seems to be nothing I can do to move it. I did have the same issue with the nut above it but I have a set of "rounded nut" removers and those things are awesome! Got them at Harbor Freight.
So I am pretty much stuck right now trying to look for any ideas as to a way to get this last bolt off. Once this is off I can drop the tcase seperate the tranny and engine, put in a new flex plate and redo the rear main seal and a new oil pan gasket. Of which is not leaking at all, so that sorta sucks I have to redo it.
Anyone have input on the correct depth the rear main one piece seal has to go in? I assume flush.

Any ideas and input is appreciated.
Joel