how strong is a hydramatic ?

[MossRoad]

Isn't the theory about using a power glide with two speeds on a drag racer is that with only two gears, you are "on the pump" for a longer duration VS two shifts in a three speed? I didn't think it had anything to do with the strength of the tranny, itself.

 

[Wayne County Hose]

A powerglide is nothing but a turbo 350 with no first gear. They were used because they were lighter and had one less shift. Powerglides were used in all kinds of industrial applications and are still running sub 8 second quarter mile times today.

Hydramatic could be referring to the "turbo" family of trannys, the turbo 200, 350, 375, and 400, and I think a couple others too.

The ratings on a tranny go by torque, not horsepower. However, a slip and slide powerglide or a turbo 350 should perform quite well in the application you describe.

 

[dbdartman]

Yes, a 'Glide is good in drag racing because it only makes one shift, making it more consistent (important when bracket racing). It also helps in that the first gear is kind of high, making launch less violent (when we were still running the Torque-Flite trans, it would just as soon launch hard & high as blow the tires off at the line because of the multiplication of 1st gear). A friend of mine has run one in his Dart for some 15 years now. This car is no light-weight either, it weighs just over 3000 lbs with driver! He's only had one trans failure, & that was because he was pushing 800+ HP through a trans that was only rated for about 600-650! Even at that, it took 3 seasons before it broke! His current trans is built to handle his engine out-put now (to the tune of well over $1000). There is now only one part of that trans that's stock GM, the case! Those are even being made now to handle 1000+ HP.

As stated, it may not be the best choice for a dozer, but if you do build it with an auto trans you'll want a torque converter that stalls just below your engine's torque peak, & also as stated keeping the trans oil cool is absolutely imperative. I like the idea of having a large capacity sump (20-30 liters). I'd expand on that idea with not only a LARGE cooler just before the sump, but also one after the sump.

 

[mopacman]

I have heard of this being done in tractors and dozers but they use a standerd trans after the auto. This would help a lot on the torque and heat load on on the auto. If you dont use a second trans at leat make sure you have enough gear reduction after the auto.......Larry

 

[texbaylea]

Go with a TH 400 and put a shift kit in to get full pressure shifts - a towing kit would do it. Put a deep cast pan with cooling fins on it. The extra cooler and sump won't hurt. I think I have seen kits for external, screw on filters. Change the filter and fluid every 400 hours max. Such a transmission will last you a long time. Plus they are not hard to rebuild - I have done several and did not spend a lot for tools.

The weak point on Powerglides uised to be the reverse band. I had a '50 Chevy and broke them regularly. They were better by '54 but I would ask the question of someone using them now.

Vernon

 

[Renze]

I see i get a lot of replies: The hydramatic and other auto trannies arent very wide spread at this side of the pond.

The reason i asked, is because i have a friend in Finland: He usually borrows a 25 ton 3 axle trailer from his cousin, to haul the muck to the far fields. The trailer is actually a Mercedes dumptruck with a tandem drive, and the front axle moved to the back as a following steered axle.
The Mercedes tandem is driven through the PTO at 1000 rpm, speed is increased to 3000 rpm to match the torque ratio of the converter, and that drives the hydramatic.
Usually a 300 hp Magnum pulls this trailer. He runs a 160 hp Zetor with it.

They use this setup because otherwise its impossible to move large loads on ice and snow roads in the early spring.

 

[Toolguy]

A non-electronic THM350 or 400 would work well, IMHO. Really a very simple, stout unit, with the THM400 being exceptionally tough. I don't think there is much difference in 400s, but 350s were built according to the engine in front of them. In other words, a 350 behind a 6 cylinder engine had less plates in each clutch pack than a V-8. There was even a HD 350 that had more plates than a standard V-8. My first choice would be to get a 400 and never worry about it. Just go easy on the forward to reverse shifts and it should last a long time. Good luck.

 

[ScottAR]

There was a retro fitted bulldozer in the magazine FARMSHOW a few years back
that featured a buick 455 with TH400 (I think) and another truck manual trans in back of the auto. Farmer ran the manual is 2nd gear or somthing and the combo worked well. TBNer MarkCT ?? had a grader with a ford 300 six in it at one time. It had the truck manual in between the engine and the grader trans if I remember correctly.

 

[MossRoad]

I have a co worker who is into classic USA cars, and he knows his way into the parts trade.

I was wondering, if i found a cheap Hydramatic transmission, would i be able to get some hours out of it if i used it in a home built wheel loader or a bulldozer, with a 100 hp engine in front of it ?

The Allison automatics of fire trucks are way too expensive to buy used.

I don't think I would want a loader or dozer to shift on me while I was operating it. I would manually select first gear for most work and only let it get into drive when tramming to another location, or possibly hauling material a long distance with the bucket. The suggestion about placing a manual tranny after the automatic is a good way to get some gear reduction and would act sort of like a range selector, wouldn't it?

 

[Renze]

Yes it would need more reduction that a standard auto tranny gives... But the best solution would be some tractor rear axle portals, and a small track sprocket. Reduction at the wheel ends, instead of putting the multiplied output torque of the hydramatic through a standard 4 speed.

If i was ever going to do so, i might be off better and more reliable with some extra low end torque on the tractor which is to be converted to rubber tracks of a midi excavator... Then i could put a whole tractor on tracks, mount the blade, or a front loader, and use heavy duty components that are designed for the task.

Just the 3 axle tandem drive trailer from finland, made me wonder if they would be suitable...
By the way, when empty, they freewheel the tractor and drive only the trailer via 1000 rpm PTO and auto tranny, which gives them a top speed of about 50 km/h