GMC to fit auto box

[R Cubed]

Does anyone out there know much about the replacement truck which was used lots in Vietnam its the one with a bigger engine 302 I think and had an auto gearbox, the front is identifiable as it has large holes in the front bumper edges. Would the engine and box fit a GMC CCKW353 ?

[Gordon_M]

You are thinking about the Canadian M211 ( I think ) with slush box and auto overrun sprag drive to the front axle?

 

Never heard of anyone retro-fitting to a CCKW. The basic CCKW modification seems to be to replace the 270 with a slightly later 302, which has various advantages and seems to be a drop-in replacement as it is basically the same engine.

[R Cubed]

Yes thats the truck, interested in fitting an auto box in to a 353 to make it easier to drive maybe for the wife !!!!!

[deadline]

The 302 should bolt right up. Other than some accessory locations the engine proper is the same save for a larger diameter cylinder, and the exhaust port is slightly larger.

 

Double clutching is the fun part part of driving a CCKW. Because turning it sure isn't.

[Grasshopper]

There was an article about them in CMV a while ago. Apparently the gearboxes had an oil cooler and a lot of them cracked in winter due to insufficient anti freeze in them. A very well engineered truck when correctly looked after- then we are talking about GI's...

 

ISTR there were a few featured in a Rambo film as well. Don't think many of them came over to Europe.

[rosie]

The more we talk about this the more it's appealing to me( I think!) Can it have pink somewhere on it? And can she be called Rosie? And can Enigma paint my avatar on the bonnet?

[rippo]

Hello cubed one,

There was an auto box produced for the gmc engine, it was used in one of the american amoured cars, sorry i can't tell you which one as american truck arn't my thing :blush: (possibly the staghound?). I came across it many years ago when george saunders turned up some gmc engines and these turned out to be from these armoured cars, from what i can remember the armoured cars had two gmc engines which were handed left and right and the auto box's were part of this set up. A member of the north west club rebuilt one of the engine for his gmc and told me about them being left and right etc.

Sorry i can't be of more help but it was all about 20 years ago, but maybe this might jog the minds of other forum members.

 

Edit: Just looked on wikipedia and it is the staghound, so the bedford research hasn't replaced everything else just yet!!! Eddy 8men has had contact with george recently and will be able to give you his contact details maybe he still has the auto boxs or at least tell you where they went.

Edited September 3, 2010 by rippo

[Grasshopper]

I would have thought that being an SAE bellhousing it would be fairly easy to find an auto gearbox that would fit the engine. Getting bored with gear changing towing the gun Rich? If changing the gearbox you may as well stick a diesel in as well...or just change the engine? We reckon that a cummins 4B would fit nicely and could be programmed to have the same power characteristics as the petrol engine (which is easily done) with all the added advantages of being a turbo diesel.

[R Cubed]

No not me at the moment I am quite happy double de clutching and struggling up the hills, but might be considdering a 353 for Rosie and while I think she could master the double de clutching bit, I think it would be better for a full auto, thinking about it a diesel might be a good idea to ....... hmmmm got to get a truck first.

 

So a Cummins diesel any idea what auto would fit and be able to cope with the truck and load of say 8 tons. ( truck 5 tons ish plus 3 tons ish load.... )

[TooTallMike]

Cummins 4B + Allison AT545. A suitable Cummins failed to sell on Ebay for £1,000 last week!

 

The AT545 would probably fit on the 353 anyway if you wanted to keep the GMC sound.

 

- MG

[R Cubed]

Cummins 4B + Allison AT545. A suitable Cummins failed to sell on Ebay for £1,000 last week!

 

The AT545 would probably fit on the 353 anyway if you wanted to keep the GMC sound.

 

- MG

 

Thanks Mike, I suppose you know the spec of these engines !! would they have a higher max revs than 2750 ? what about HP ? what would they have been fitted to if they are only 4 pot I thought most trucks over 3 to 4 tons were 6 pot ?

[Grasshopper]

They were fitted to Dennis Dart busses (6/7 tonne) for a while when EURO3 emmisions were required. They were able to revert back to 6 pot at EURO4. Someone did explain all the mechanics of it to me once, but I've forgotten it. Also may have got my EURO numbers a bit wrong, but I know new road vehicles are currently meeting EURO5 standards.

[TooTallMike]

It's a widely used engine in the states. Most UPS-type vans over there have them in. Over here they are more commonly used for marine and generator applications. Ford/New Holland tractors used them too, and that would probbaly be the best place to find one with an injection pump suitable for road use.

 

Regarding the rev range it would be at least comparable to the GMC, if not higher. I don't know the specific power output without looking it up, but I would guarantee it would be greater than a GMC engine.

 

Unfortunately you need to give some consideration to the machinery further down the line - specifically the transfer box, props and axles, not to mention the braking system. I'd be inclined to rebuild all of these with new components at the same time as installing a diesel, and even then there is no guarantee they can take the torque. If fuel economy were removed from the equation I'd look at putting the auto box on the petrol engine. I would suggest teaching Rosie to double de-clutch but I suspect this is more of an engineering project than actual necessity...?

 

- MG

[N.O.S.]

Would not putting a modern gearbox on the back of a GMC engine entail making an adaptor plate or new complete rear housing?

 

Because I didn't think there was anything remotely SAE about the GMC 270's rear end.

 

Putting a GMC gearbox on any other engine will also require one - unless it is a Bedford 330 or similar in which case only the lower two of the four gearbox mounting bolt centres are different, and Bedford combined flywheel/bellhousing can be drilled to suit.

 

Interesting that the Bedford and GMC combined flywhel and clutch housing are similar but not identical - Bedford adopted Chevrolet designs but didn't make it all totally compatible for some reason.

 

Modern engines use a flywheel housing with SAE flange, gearboxes have a seperate bolted-on or designed-in SAE bellhousing (clutch housing) to join box to engine.

 

Note - using a Bedford 330 means cutting bulkhead or pushing radiator forward or both as it is too long.

 

The Studebaker I think had an SAE bellhousing to mate up with the SAE flywheel housing of the Hercules JXD, but I'm not sure if the gearbox mounts were the same as GMC? Wasn't it a different gearbox in the Studebaker? But this might be a really useful item if you want to put the GMC box on a more modern motor.

 

The only other GMC flywheel/bellhousing I know of made for the GMC was the Perkins produced P6 conversion, but I don't think that will help on more modern engines, and you probably don't want to install a P6.

 

TTM's idea of a modern engine and box - be it auto or manual - might be much the easier option. Finding gearboxes with a straight stick shift is not easy. And using a more modern remote shift box (for example a Leyland Roadrunner ZF combined gearbox / bellhousing from a Cummins B6 which would fit onto a B4) would entail engineering a whole new gearchange mechanism (but not impossible if you really like projects :cool2:).

[Degsy]

You are thinking about the Canadian M211 ( I think ) with slush box and auto overrun sprag drive to the front axle?

 

Never heard of anyone retro-fitting to a CCKW. The basic CCKW modification seems to be to replace the 270 with a slightly later 302, which has various advantages and seems to be a drop-in replacement as it is basically the same engine.

 

The Canadian assembled M135, M211 etc were virtually identical to the GMC range introduced to the American army in 1950. They all used the 302M engine and Hydramatic 4F1Rx2x1 autobox. I don't think fitting the engine would cause any problem as it is a common conversion in the USA, however I doubt that it would be so easy to use the autobox because of the sprag drive to the front axle. I think you might have to import the engine and gearbox from either the USA or Canada as they are not easily obtainable this side of the pond.

[TooTallMike]

I followed the earlier assumption that they had an SAE flywheel housing. If not, it must be smaller than SAE 1 (13" clutch) as any larger American engine of that period would presumably have been standardised on SAE 1/2/3. It's very likely to be some sort of standard design so would the 'box from a more modern pickup fit? eg. Chevy Blazer etc. You'd have to do some calcs on engine speed vs. output speed. Also beware of overloading the 'box although most have remote oil collers which would address this.

- MG

[abn deuce]

You might want to post the question or search on the GMCcckw site as I know Dr. duce has answered the questions on re engining CCKW's and pros and cons as well as putting the 302 in to the cckw.

[R Cubed]

The 302 should bolt right up. Other than some accessory locations the engine proper is the same save for a larger diameter cylinder, and the exhaust port is slightly larger.

 

Double clutching is the fun part part of driving a CCKW. Because turning it sure isn't.

 

Yes I am aware of the 302 and the fact it will almost fit straight in, depending on the exact model and year of the 302. But that engine is still petrol !! and was thinking if I fitted a diesel it would be a bit more economical !

[R Cubed]

I would have thought that being an SAE bellhousing it would be fairly easy to find an auto gearbox that would fit the engine. Getting bored with gear changing towing the gun Rich? If changing the gearbox you may as well stick a diesel in as well...or just change the engine? We reckon that a cummins 4B would fit nicely and could be programmed to have the same power characteristics as the petrol engine (which is easily done) with all the added advantages of being a turbo diesel.

 

Not really a problem for me but might be thinking of a 353 for Rosie as a load carrier, she could well get the hang of double-de clutching but the thing which gives me the willies is if she was to miss a down change going down hill !!! think she might panic. If she is going to drive one I want to try and make it as easy as possible so she gets to like it rather than having to drive it.

[R Cubed]

They were fitted to Dennis Dart busses (6/7 tonne) for a while when EURO3 emmisions were required.

 

Are you talking about the engine or both the engine and gearbox ?

 

It's a widely used engine in the states. Most UPS-type vans over there have them in.

 

Unfortunately you need to give some consideration to the machinery further down the line - specifically the transfer box, props and axles, not to mention the braking system. I'd be inclined to rebuild all of these with new components at the same time as installing a diesel, and even then there is no guarantee they can take the torque.

 

MG

 

With ref to the UPS vans in the states would you have any idea what the gross weight would be for one ?

 

As the truck has a low range would the torque not be multiplied lots, so even with a larger diesel engine in high range the torque would be less than in a low range gear ? Also with the potential for 5 Tons load on road, which it would be nowhere near ! What do you think ?

 

Would not putting a modern gearbox on the back of a GMC engine entail making an adaptor plate or new complete rear housing?

 

Because I didn't think there was anything remotely SAE about the GMC 270's rear end.

 

Putting a GMC gearbox on any other engine will also require one - unless it is a Bedford 330 or similar in which case only the lower two of the four gearbox mounting bolt centres are different, and Bedford combined flywheel/bellhousing can be drilled to suit.

 

Interesting that the Bedford and GMC combined flywhel and clutch housing are similar but not identical - Bedford adopted Chevrolet designs but didn't make it all totally compatible for some reason.

 

Modern engines use a flywheel housing with SAE flange, gearboxes have a seperate bolted-on or designed-in SAE bellhousing (clutch housing) to join box to engine.

 

Note - using a Bedford 330 means cutting bulkhead or pushing radiator forward or both as it is too long.

 

The Studebaker I think had an SAE bellhousing to mate up with the SAE flywheel housing of the Hercules JXD, but I'm not sure if the gearbox mounts were the same as GMC? Wasn't it a different gearbox in the Studebaker? But this might be a really useful item if you want to put the GMC box on a more modern motor.

 

The only other GMC flywheel/bellhousing I know of made for the GMC was the Perkins produced P6 conversion, but I don't think that will help on more modern engines, and you probably don't want to install a P6.

 

TTM's idea of a modern engine and box - be it auto or manual - might be much the easier option. Finding gearboxes with a straight stick shift is not easy. And using a more modern remote shift box (for example a Leyland Roadrunner ZF combined gearbox / bellhousing from a Cummins B6 which would fit onto a B4) would entail engineering a whole new gearchange mechanism (but not impossible if you really like projects :cool2:).

 

Dont think I want to go down the route of an auto on the original engine, not that they are damn fine engines, did think of the Bedford MJ ? but as people have said it is longer than the 270 so would need lots of jiggery pokery to fit, just airing towards diesel with manual syncro or auto box.

[R Cubed]

 

 

TTM's idea of a modern engine and box - be it auto or manual - might be much the easier option. Finding gearboxes with a straight stick shift is not easy. And using a more modern remote shift box (for example a Leyland Roadrunner ZF combined gearbox / bellhousing from a Cummins B6 which would fit onto a B4) would entail engineering a whole new gearchange mechanism (but not impossible if you really like projects :cool2:).

 

On remote gear change boxes does the selector not just come up out of the top of the box and then have the strange wobbly rods and bushes ect to get it to the cab ?

[N.O.S.]

Sadly not (though I have only limited knowledge of new boxes) - gearboxes are now often designed so that by having two actuator rods coming out of the box the strange wobbly linkage can be simplified somewhat :cool2:

 

To be honest the number of trucks with suitable stick shift boxes still coming into breakers are getting very few in number.

Edited September 9, 2010 by N.O.S.

[TooTallMike]

If it's an auto gearbox with a cable operated change the selector can go anywhere the cable will reach. On some manual boxes with remote-operation linkage the top of the box has a reversed gear layout as the linkages terminate in a class one lever with the gear knob on top. You could plonk a stick straight on top of the bit poking out of the 'box, but if you're worried about a driver's reaction in a panic situation this may not be the best approach...

 

- MG

[TooTallMike]

For all your 4BT information requirements see www.4btswaps.com !

 

- MG

[N.O.S.]

Could any Studebaker experts out there advise on the similarity/difference between GMC and Studebaker gearboxes, please?