Using my truck tranny

[smitty2]

I was wondering if using the transmission from my old wood hauler ( 81 Chev 1 ton, 454, 5 speed.) is an option for a comp coupe car? I believe it's a Muncie since it came in a GM product. Since the time shifting between gears is not measured in milliseconds, and the 3rd, 4th, and 5th gear spread seems to be fairly close. This tranny is "Hell for stout", because I've had it detained in a muck hole with at least a cord of wet Alder on board. Seems to me this would be a good way to get the center of gravity down low since it weighs at least a ton.
 If anyone has had any experience with these beasties I would sure appreciate some feed back... Otherwise I can use it to keep my boat from floating off.

Thanks...          Smitty from the Great North Wet

[Sumner]

Is it like the newer GM 5 speeds with the Granny 1st and overdrive 5th??  If so 1s probably won't do you much good and there can be way too much rpm drop going into an overdrive 5th for the motor to overcome at high speed.

Find out what the ratios are of each gear and plug them into a spreedsheet ( I have one on my site ( HERE )  that will work) and see what speed you have in different gears and more important the rpm drop on the shifts to see if your motor will stay in the power band.

Good luck and c ya,

Sum

[ddahlgren]

Get ratios off trans get projected or known data from dyno get gearsplit see if you have an issue..
Dave

[smitty2]

Hi Sum! Nice to hear from you again
 Yea it's a granny tranny with 5th being an OD. I will have to drag this monster out from under the pile of really important stuff so I can get some numbers off of it. I'll research this some more. Thanks for the lead on the spread sheet... I'll check that out too.

Thanks again....        Smitty

[Richard Thomason]

I won't even pretend to understand what I know. We started out with a TH400, for a while with converter and then later without. Back then we were learning quickly and speeds went up very easily in fairly big chunks. When we changed to a 5-speed, we thought it would make huge difference. The funny thing was, the first run we had problems with the air shifter and it went from first to third to fifth. Fixed the problem and went right back out and used all five gears. We gained like two mph, from 306 to 308. This was with a 292 cid turbo setup on gas. We have had other puzzling things over the years but I do agree with the conventional wisdom that says to keep the splits very close on the top end. Maybe when and if we can ever put a full full together with our current setup, 433 cid NA on fuel I can tell you how well our new ratios work. We have a very tall first gear and tighten up as we shift.

[smitty2]

Seems to me that the 3rd to 4th split was really close, but 5th was somewhat of a stretch. I'm sure 5th was an OD. I have a truck tranny that does not have an overdrive gear... just a 4 speed with granny. It does not have as wide a gear split from 3rd to 4th.
 My main question is that these monsters would be strong enough? I have a whole corner of my shop dedicated to these things, and I either have to use em or get rid of them. Since they are a dime a dozen in this area I figure what the heck

 Happy Holidays....       Smitty

[Sumner]

I won't even pretend to understand what I know ............

........ When we changed to a 5-speed, we thought it would make huge difference. The funny thing was, the first run we had problems with the air shifter and it went from first to third to fifth. Fixed the problem and went right back out and used all five gears. We gained like two mph, from 306 to 308.........

....but I do agree with the conventional wisdom that says to keep the splits very close on the top end. Maybe when and if we can ever put a full full together with our current setup, 433 cid NA on fuel I can tell you how well our new ratios work. We have a very tall first gear and tighten up as we shift.

I really wanted to go to a 5 speed for next year with Hooley's Stude, but after an e-mail from Tom I feel for us right now 4 speeds is fine and maybe even better. Hooley is going to order a re-furbished G-Force GF4A 4 speed from them this next week with the gears we want.  Some cars and bikes can still benefit from more than 4 speeds you just have to look at all the variables.

If you are interested in what probably happened in your case and why you did as good with the 3 speeds as the 5 you can read the comments from Tom near the bottom of THIS PAGE.

c ya,

Sum
 

[Richard Thomason]

Interesting read concerning the number of gears to go fast. If not always, at least for a time, the Hoffman liner ran TF 2-speed with converter. A couple of things about the 5-speed (we run a g-force), that 300 rpm split going into 4th and then again into 5th sure does sound sweet. I have always been afraid of overdrives, they are inherantly not as strong. Drag race dog type trans does not necessarily pop out of gear when you back off the throttle. We use a air solenoids on the shifter and when you get back on the power it is still in gear, no problems. We also run a Casales-type overrunning sprag on the input shaft to the quick change. NEVER EVER EVER come down on compression in a front wheel drive car, really bad things can and will happen.

[Sumner]

Interesting read concerning the number of gears to go fast. If not always, at least for a time, the Hoffman liner ran TF 2-speed with converter. A couple of things about the 5-speed (we run a g-force), that 300 rpm split going into 4th and then again into 5th sure does sound sweet.

The 5 speed would give you a definite advantage over the 4 speed in having two really small spits between 3rd and 4th and 4th and 5th.  Something that could be advantages to a really fast car like yours that is trying to accelerate to high speeds in the distance available.  I would like one also, but out of our budget now and probably not needed for a 250 mph car.

Drag race dog type trans does not necessarily pop out of gear when you back off the throttle. We use a air solenoids on the shifter and when you get back on the power it is still in gear, no problems. 

I imagine this is in response to my comment about transmissions setup for the drags on that page. 

You do not want the "drag" ones. They are designed to pop out of gear as soon as you let off the power so they can slam them into the next gear on the drag strip.

  Yes not all drag transmissions are setup like this, but some are and I just wanted to let someone know that might be buying a used one to make sure they don't end up with one of these (no fun driving at over 200 and having to hold the transmission in gear with one hand as you get in and out of the throttle ).  When I talked to Jerico they said they could make one for LSR and would still work good at the drags, just not quite as good as one that was optimized for the drags.  We have looked into this since Hooley drag races and with a different gear set (about $1300) he could do both with one transmission.

We also run a Casales-type overrunning sprag on the input shaft to the quick change. 

Where can I find out more about this application???....and thanks for the other input.  Good stuff there.

c ya,

Sum

[jimmy six]

Smitty-Without all the other BS you can use any tranmission you want if it suits your purpose.  Just think you will placing a lot of weight right where you need and want it..Good Luck