Duplex Shift Technique

[b61fred]

Fred,

I have tried that method and it definitly does not work. The shifter will not pull easily out of gear at any speed except at all STOP. Just like my SuperM's you have to stop before shifting into any gear.

mike

sounds like you might want a different trans... I have a triplex for sale

Fred

[Mike]

Sounds good to know that another trans is out there and ready for delivery, but I'm going to hang on until I can get more active with this truck.

Thanks

mike

[Mike]

Fred,

If Rob is coming over I bet it will cost a plenty. And if he is to be a cameraman, I figure you may stick him out on the hood and he can video the shifting through the window. This way the cab will not be steached out of proportion. It's very difficult to find a cab reducer tool. I also hope he can get along with the chrome dog on the hood since he's a bit larger than it.........LOL

mike

[Red Horse]

Hello,

My b61 has a 237 with the old trd720 trans behind it, I have found that if I split the shifts the engine don't pull as hard. I think it will save the trans. I don't know for sure but it has worked well so far. As for your original question... The way I shift my truck is to start in 1st and lo, then hi. Then you should shift the main to 2nd, let the clutch out, this spins the input shaft of the auxiliery trans up to speed and then clutch and shift the aux. to lo. Repete this all the way through unless you have a overdrive then 4 th-hi, you shift to 5th and leave the aux in hi. To know if you have a overdrive front box, see if the number ends in 0, should be like trd7220 or 720 or if it still has the little trans trd670( i have seen these behind diesels) If you have any more problems maybe I could video my duplex like freightrain.

Fred

Fred, Well I got underneath it. And it is in fact a TRD 720. Like I said, I will use this truck (has an 8 yard box on it) so I guess I show it some respect and keep my fingers crossed. Your Maxi/Duplex is a tractor and do you ever pull any weight?

[other dog]

I will try and do a video, Rob is going to come over in a week or two. maybe I can talk him into playing camera man. That is if we can get both of our rageing fat-a$$es into the cab of a B model. I may need some pointers on how to load a video on to the site.

As for your grinding, Try shifting with out the clutch and see what happens, It sould go in whe the RPM is right, or it should I guess??

Fred

speaking of videos, this is about the best triplex shifting video i've seen. you can tell this guy's done this a few times!

[b61fred]

I pull a semi trailer with about 4 or 5 antique tractors(farm type)on it. I don't know the weight but It look neat pulling in to the shows with it. The clutch will "protest" if I don't split the gears loaded. If I drive it like a straight 5 speed it wants to slip a little at 1600 rpm. I guess the splits don't load the engine enough to spool the turbo hard. Sounds good though. I have plans to play video man tomorrow.

Fred

[HK Trucking]

speaking of videos, this is about the best triplex shifting video i've seen. you can tell this guy's done this a few times!

His 4th hi split to 5th lo split shifting was kinda "grindy", other than that, not bad.

[Wayne Elliott IV]

This was a helpful discussion for me to read since I have been trying to figure out how to shift the two stick setup of unknown origin in our truck for a while.  Still probably just need to practice but may have learned a few things here.  What I'm probably dealing with is a transmission not mated to the right motor, or a motor that refuses to idle down quick enough to shift okay.

In reply the the bit about clutchless shifting, and Mike's post on the previous page:

This may be a dumb assumption that you guys probably all know, but I can pull almost anything including a 90s f150 out of gear and upshift (well, on a single main...) by putting pressure on the stick toward the next gear as I let off the accelerator and the acceleration of the truck shifts.  In between the transition from accelerating or moving under power to having the engine slowing the truck down (engine braking, sort of. not jake brakes), there is a place where no pressure is in the drivetrain and it will slip right in the next gear.  Frustrating and stupid to do when lugging the truck, gears will make bad noises.

If a transmission won't come out of gear like this, something may be wrong.  Once at work a PTO out of adjustment got a GMC "hung" in first gear.  That was frustrating.