Transmission recommendations???

crazycal · 09-13-2019, 09:25 PM

Greetings to all. It has been many, many moons since I've posted here. It is time for me to get my 1994 International Tiny Big Bus finished and on the road. Engine is a DT408.

I've been trying to figure out a good overdrive transmission to replace the AT545. My guess I'd a 6 speed manual transmission. I do not want any computers in my drivetrain. This is not a big bus and not very heavy. I may pull a toad so I do not want a non lockup converter. Any suggestions or recommendations would be greatly welcomed. I will try and post a picture soon.

crazycal · 09-13-2019, 09:30 PM

Maybe a 7 speed or 8, 9 or 10 speed.

EastCoastCB · 09-14-2019, 03:24 AM

Quote:

Originally Posted by crazycal

Greetings to all. It has been many, many moons since I've posted here. It is time for me to get my 1994 International Tiny Big Bus finished and on the road. Engine is a DT408.

I've been trying to figure out a good overdrive transmission to replace the AT545. My guess I'd a 6 speed manual transmission. I do not want any computers in my drivetrain. This is not a big bus and not very heavy. I may pull a toad so I do not want a non lockup converter. Any suggestions or recommendations would be greatly welcomed. I will try and post a picture soon.

Most of the medium duty stick shifts don't have OD from what I've seen. Maybe go with a real class 8 unit!
Why wouldn't you want the converter in an auto locked for towing??
643 would probably be the easiest swap. But if you want OD then a 2000 would get you that and lockup.

crazycal · 09-14-2019, 03:29 AM

A 643 is an option but it is still one to one final. I really want overdrive. I do not want an electronic transmission.

EastCoastCB · 09-14-2019, 04:26 AM

Quote:

Originally Posted by crazycal

A 643 is an option but it is still one to one final. I really want overdrive. I do not want an electronic transmission.

I hear ya.
The current shorty I have came with a 545 and I've only ever had one bus with OD.

cadillackid · 09-14-2019, 07:56 AM

stick shift == Yuck.. cumbersome to drive the older truck stick transmissions.. clunky to say the least..

spend some $$ and put a 2 speed rear end in and an MT-643. if OD is that important.

otherwise go electronic.. Love my 6 speed electronic trans..

the MT-643 in my dev bus made it a whole different bus.. with 11R tires on it and lockup with a 4.78 rear I can easily cruise 65 and my engine is at about 2600 RPM or so (DT360).. it climbs hills a little slow but not nearly as slow as it did with a 545..

a DT408 with the pump screws twisted out a bit.. 11R tires and a 5.13 rear is likely a good 65 MPH cruiser with an MT-643..

PNW_Steve · 09-14-2019, 12:42 PM

Here is a 7 speed OD syncro medium duty transmission.

Medium & Heavy Duty Truck Transmissions

crazycal · 09-14-2019, 07:34 PM

Quote:

Originally Posted by PNW_Steve

Here is a 7 speed OD syncro medium duty transmission.

Medium & Heavy Duty Truck Transmissions

http://www.tremec.com/anexos/Literat...ansmission.pdf

Thanks.

Any idea of price? I will call on Monday.

crazycal · 09-14-2019, 08:26 PM

Quote:

Originally Posted by cadillackid

stick shift == Yuck.. cumbersome to drive the older truck stick transmissions.. clunky to say the least..

spend some $$ and put a 2 speed rear end in and an MT-643. if OD is that important.

otherwise go electronic.. Love my 6 speed electronic trans..

the MT-643 in my dev bus made it a whole different bus.. with 11R tires on it and lockup with a 4.78 rear I can easily cruise 65 and my engine is at about 2600 RPM or so (DT360).. it climbs hills a little slow but not nearly as slow as it did with a 545..

a DT408 with the pump screws twisted out a bit.. 11R tires and a 5.13 rear is likely a good 65 MPH cruiser with an MT-643..

The 2 speed rear is an option but I have never had any experience with one. 2600 RPM is a no go. I can not stand that high of RPM. Maybe a VW diesel. What 6 speed do you have?

EastCoastCB · 09-14-2019, 09:32 PM

Quote:

Originally Posted by crazycal

The 2 speed rear is an option but I have never had any experience with on. 2600 RPM is a no go. I can not stand that high of RPM. Maybe a VW diesel. What 6 speed do you have?

With the 3.42 gearing I've got in my bus I'm getting about 1800 rpm at 65mph. I've got a 545. Not ideal but it works for now.
This bus is super quiet going down the highway. I agree- 2600 is just too much rpm!

crazycal · 09-16-2019, 12:10 AM

That 7 sp. seems to be more than I would like to spend, but I have found some MD3060 trannys in the $1500 range.

This is the bus that I want the transmission for.

http://www.skoolie.net/forums/f27/he...tml#post348829

EastCoastCB · 09-16-2019, 03:13 AM

That's a real nice shorty.

cadillackid · 09-16-2019, 04:54 AM

For that, regear and a MT643, while I love my Allison 6 speed swap, it wouldn’t be near as good of the engine were mechanical , the electronic trans operate much better with electronic engines..

Gear wise , any idea what axle that has? My shorty has an S110/135 with a 3.54 gear that I want to go shorter on, like a 4.10 or 4.30, if yours is same axle maybe a trade is in order...

EastCoastCB · 09-16-2019, 04:58 AM

Cal you could probably do a 643 and gear swap for less than a grand if you shop around.
Or if you both have ratios that would work hit up Chris for that axle swap.
I've got a 5 window shorty and don't feel the need for more gears with the 3.42 in the rear.

crazycal · 09-16-2019, 09:07 AM

I think the rear is a 4.78, something like that. The bus is more than 100 miles away right now. Plus the tires are 9r22.5 with skinny pizza cutter wheels that are 6 lug. Finding rim's that will take 11r22.5 will not be easy. I have that MT653 from Vegas.

2000 is my sweet spot in that is what I'm shooting for. The power stroke and Cummins engines that I have had seemed to get the best mileage at that RPM or a little bit lower.

Booyah45828 · 09-16-2019, 10:14 AM

Quote:

Originally Posted by crazycal

Greetings to all. It has been many, many moons since I've posted here. It is time for me to get my 1994 International Tiny Big Bus finished and on the road. Engine is a DT408.

I've been trying to figure out a good overdrive transmission to replace the AT545. My guess I'd a 6 speed manual transmission. I do not want any computers in my drivetrain. This is not a big bus and not very heavy. I may pull a toad so I do not want a non lockup converter. Any suggestions or recommendations would be greatly welcomed. I will try and post a picture soon.

Welcome back Cal! I was wondering where you've been the last couple years. Good to see you on again.

They make 5,6, and 7 speed transmissions with an OD. but the gear spacing is so huge I don't think it's desirable in anything but a gas engine. And anything that has more gears would be considered more HD then MD.

I'd avoid the 2 speed rear axle idea as an OD, they weren't really designed for that type of service.

I'd personally do a re-gear with an mt643 upgrade. That will work easiest and you won't have to source all the parts for a manual transmission swap, which can be a headache.

Didn't you have an at1545 at one time?

SolomonEagle · 09-16-2019, 10:42 AM

I have put a bit of thought into this myself.od trannys are hard to come by for our application. I have a 5 speed Spicer currently and, besides no overdrive, it just isn't enough gears to drive like you think a manual bus should. If I were looking at anything with less than 7 gears, I would just go with the 643 as medium size of tranny's can cost anton as they are highly sought after. As for a class 8 tranny..try finding one with a sae#2 bellhousing..pretty hard. Also, I don't know how well something that heavy would work out in an sae#2 setup. I would just go with a 643 or whatever 6-7 speed I could find and change the rear gears accordingly.

crazycal · 09-16-2019, 10:42 AM

Quote:

Originally Posted by Booyah45828

Welcome back Cal! I was wondering where you've been the last couple years. Good to see you on again.

They make 5,6, and 7 speed transmissions with an OD. but the gear spacing is so huge I don't think it's desirable in anything but a gas engine. And anything that has more gears would be considered more HD then MD.

I'd avoid the 2 speed rear axle idea as an OD, they weren't really designed for that type of service.

I'd personally do a re-gear with an mt643 upgrade. That will work easiest and you won't have to source all the parts for a manual transmission swap, which can be a headache.

Didn't you have an at1545 at one time?

Thanks. I've been working around the clock and might have taken its toll on me. That's what Im going to get this project off the ground and finished.

I do have a 1545 hidden in the closet somewhere. You sir are too smart for me. I will have to ddig that one up because I believe 10 feet under.

crazycal · 09-16-2019, 10:53 AM

Quote:

Originally Posted by SolomonEagle

I have put a bit of thought into this myself.od trannys are hard to come by for our application. I have a 5 speed Spicer currently and, besides no overdrive, it just isn't enough gears to drive like you think a manual bus should. If I were looking at anything with less than 7 gears, I would just go with the 643 as medium size of tranny's can cost anton as they are highly sought after. As for a class 8 tranny..try finding one with a sae#2 bellhousing..pretty hard. Also, I don't know how well something that heavy would work out in an sae#2 setup. I would just go with a 643 or whatever 6-7 speed I could find and change the rear gears accordingly.

The manual transmission idea is out the window as of right now. But I do thank you sir.

cadillackid · 09-16-2019, 01:39 PM

the AT1545.. do your homework.. there is / was a thread aboiut the perils of getting one of those to work..

it appeared to be the solution to a lot of issues which was the idea of a drop-in for an AT545 with lockup.. I remember there being major differences in the land of the converter offset and bolt patterns..

a MT643 swap wasnt too bad.. I did one and it was well worth it..

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