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IH Cub Cadet Forum * IH Cub Cadet's larger relatives. * Let's talk Torque Amplifiers < Previous Next >

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Home of the Plow Special (Aaytay) on Sunday, February 27, 2011 - 09:00 pm:

Thanks for all of the info on the Torque Amplifiers. You guys are the best!

School has now ended...

Now collecting tractor serial and engine spec numbers for the 169/1650 data-base. Please email me for more info!

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Dennis Frisk (Dfrisk) on Saturday, February 26, 2011 - 01:53 pm:

WAYNE - I couldn't teach a "tractor" course, I'm BIASED. I won't mention any brands but the worst days of my life have been spent on 2-cylinder tractors listening to Pop-Pop-Pop for hours on end.

I'd sure like to find Dad's old '54 Super M-TA. Make a sharp pair of "Book End '54's" with the Super H.

Wyatt and I agreed that a clutched planetary out of a small car auto. trans would make a good start for a T-A. Instead of a 4:1 reduction like the creeper we'd need something like a 1.25:1 to 1.5:1 reduction.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Wayne Shytle (Wshytle) on Saturday, February 26, 2011 - 10:08 am:


If you ever need any extra cash you could go to any community college and just teach tractors...or do you already? Good write-up!

T/A on a there's something to think about.


Feel educated? The topic makes for some good learnin'.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Dennis Frisk (Dfrisk) on Saturday, February 26, 2011 - 07:43 am:

GEESH ART - If ya got questions don't be afraid to ask! (Art & I have exchanged a half dozen e-mails the last two days!

Early T-A's were a dry clutch operated planetary gear reduction unit with an over-running clutch located between the engine clutch & transmission, in fact the small T-A's the output gear was the constant mesh and 5th gear driving gear inside the transmission.

As Paul R said, the planetary gave 33% speed reduction while increasing pull power 45% according to IH. The over-running clutch used was a "ramp & roller" design so when the T-A clutch engaged there was no lurch against the already loaded gears in the trans & rearend unloading them then quickly loading them again in the low range. The T-A shift was a seamless increase in gear reduction, no break in power because of that over-running clutch. The newer style T-A's use what they call a "Mechanical Diode" but I've never actually seen one so I can't really describe their operation.

The first T-A's in the SM-TA had a bolt-together housing and ALL later T-A's used a more durable 1-pc casting. The same basic T-A unit (with the exception of that case) was used in EVERYTHING from the SM-TA (1954 vintage) up thru the 686 last produced in 1980 regardless of tractor size & HP.

Most problems with the T-A's were with that over-running clutch. As the ramp & rollers wore the rollers got flat spots and the ramps wore where the rollers ran and they would not "Catch" which allowed the tractor to just stop when the low side of the T-A was engaged. Shifting fast, no feathering into & out of T-A, allowed the rollers to securely seat themselves. Also allowing them to free-wheel by engaging T-A and letting the tractor coast accelerated wear on the O-R clutch. Always best to ONLY pull the T-A back when under load.

The later BIG frame T-A's were a totally different design and only had a 22% speed reduction. They were built to transmit 100+ HP also.

When doing field work in varying soil conditions and hills the T-A let you use the gear that gave you the best speed in good conditions and still pull thru the tough spots & hills or slow down for turns. A real productivity improver. Normal operation was to let the engine pull down from full load RPM, SM-TA, 400/450 ran 1450 RPM so about 1000 RPM and pull the T-A back and the engine speeds back to 1450 as quick as it can and picks up the load, 300/350's ran either 1750 or 2000 RPM so either 1150 RPM or 1300 RPM. Once the tractor cleared the hill or tough spot and the engine was running at speed and not laboring, squeeze the release handle and let the T-A lever fly forward and the tractor smoothly accelerated back to full speed for that gear.

The operator's manual had pretty explicit instructions for adjusting the T-A clutch and engine clutch. Those instructions should be followed. The T-A linkage effected the disengagement of the engine clutch and lots of times pulling the T-A back was required to reduce the bind the engine clutch was causing on the sliding gears in the transmission. As with all mechanical things, wear in the linkage pivots after 50+ yrs of use can make adjusting them difficult.

From what I understand a good new H-D remanufactured T-A costs between $500-$600. Bad part is to R&R a T-A requires splitting the tractor between the clutch housing & transmission. Best way to keep them healthy is to USE them and adjust them as needed.

Wyatt & I had MANY laughs watching the PD #1 video, I was caught on tape reaching for the T-A lever on my CC #72 to slow down at the end of my first round up by the barns. Some 40 yr old habits die REALLY hard. We talked about how a T-A could be built for use in a CC. I might just try that some day! It would NOT have the O-R clutch like production T-A's had, it'd be more like the prototype T-A's IH built in a couple H's back in 1951.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Tom Hoffman (Thoffman) on Friday, February 25, 2011 - 04:55 pm:

Art, Kinda' like a "Automatic" creeper.

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Marlin Homrighausen (Mhomrighausen) on Friday, February 25, 2011 - 04:17 pm:

Torque Amplifiers are generally of two kinds. The first ones were setup to be freewheeling when pulled back and put into service. By that I mean there wasn't any mechanism to hold the tractor back when you were going down a hill while traveling on a road if you engaged the TA. When you travelled down a road you had to make sure to have the torque amplifier in the non engaged position to prevent the free-wheeling. I believe all the way up to and including the first 06 Series had this kind of Torque Amplifier in them.

The later TAs I believe feature a sprague type clutch (Dennis F. will correct me on this if I am wrong). That helped keep the tractor from free-wheeling when going down a hill when driving on a road. There was/is a drawback to even this type of hold-back system. When the TA becomes worn enough this hold back becomes weak and the free-wheeling effect once again comes into place.

Hy Capacity Products introduced a greatly improved Torque amplifier for IH tractors back in the late 80s or early 90s. If I recall it featured a type of lock up clutch similar to what helicopter rotors use. It was advertised as being built so rugged that it will quite possibly be the last TA your FARMALL will ever need. I remember the skepticism that some IH dealers had about isntalling them over the IH ReMan TAs. They feared the Hy Capacity would be so hard that it would tear out your regular tractor's clutch. Overtime these fears were proved unfounded and now the Hy Capacity is one of the most widely accepted aftermarket TA replacements offered.

Now we'll let Dennis F. take over.

Having trouble with your Cub Cadet Hydro transmission? ® CLICK HERE

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Paul W.Roessler (Proessler) on Friday, February 25, 2011 - 09:24 am:

T/A first were used by IH on Farmall Super MTA. SMTA has a 5 speed transmission , with the TA it doubles speeds/gears to 10. It also works on reverse gears. If plowing in 3rd gear & were pulling up a hill or tough spot that U would have to stop & shift to a lower gear, with TA just pull back TA lever & plow on with about 33% less speed & more pulling torque to go thru tough spot.Then release TA lever to go back to previous speed (direct drive). All done without stopping. Driving on the road, the older Farmalls would free wheel in TA going down a hill. Denny , I'm sure can fill in the mechanicals. Check Red Rower Magazine Forum...too.

882 Diesel...PWR

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Kraig McConaughey "Keeper of the Photos" (Kmcconaughey) on Friday, February 25, 2011 - 09:10 am:

Art, I just emailed you some pages from a book that has some info. I'd post it here but due to possible copy right issues I think it best not to...


Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Charlie "Digger" Proctor (Cproctor) on Friday, February 25, 2011 - 09:09 am:

It's easy, with the handle back, you go slow, push it forward and you go faster!
Glad I could clear that up for you.

"Every Cub has beauty but not everyone sees it."

Move Post (Moderator/Admin Only)View Post/Check IPDelete PostEdit PostBy Home of the Plow Special (Aaytay) on Friday, February 25, 2011 - 05:52 am:

I need some "schooling" on T/A's...

1) How do they work from a mechanical point of view?

2) Operationally, when are they used?

3) In reading ads of tractors for sale I see many people commenting that the T/A on their particular tractor is either "good", or "needs work". What goes wrong with these things and how difficult are they to work on?

While I usually understand basic mechanical devices, I have no practical experience using a T/A, so any light you could shed would be greatly appreciated.

Now collecting tractor serial and engine spec numbers for the 169/1650 data-base. Please email me for more info!

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