I've been a member of this forum for quite some time. Any questions I have I can usually search the site and get them answered.
you guys are great. I have a 50 F1 and was thinking of the T5 tranny swap but got to thinking that the first gear is so low that maybe I be just as well off raising the rear end gears. What do you guys think? the truck is stock except for a 12 volt system.

 

I am confused as to what you are asking, so forgive me if I sound stupid. If you are talking about the "granny" low used in these trucks, changing the rear end will have little effect. Granny is on the order of a 6 to 1 reduction, most F1 rear ends are somewhere between 3 and 4 to 1.

Worse case you are looking at a total of a 10 to 1 reduction. While changing rear ratios might change that to 9 to 1, I don't think you will feel any difference.

High gear in almost all non-overdrive transmissions is 1 to 1 - so changing the rear ratio has a big effect there.

Generally speaking, granny low is used to start a heavy load, and is not used in normal driving. Most people start their trucks in second - which has a ratio like low gear in a 3 speed.

If you are looking for a close-ratio car type 4 speed where you start in low and shift through 2ed and 3rd to reach high, you have to change the tranny - changing the rear end ratio will not give you that.

 

Sanford, I'm a little confused as ***** was. What do you have now and why are you planning on making a change? Once we know that we can get to what might be the best solution for you.

 

I think he wants to use the low gear as first and raise the rear end ratio. Basicallyuse the transmission as a 4 speed with a really low 1st.
Have you found a higher rear end gear set yet? One problem you will run into is finding a higher gear for the rear end if it is factory.

 

He does mention he's looking in to a T5 swap. Assume for the OD. Could be he might be comparing the T5 1st gear vs what he has now?

My guess can be as good as yours

 

I read this question last night and passed, but I'll try today.

I like the idea of using a T5 for the OD in the final ratio. The 50 F1 had either the light duty 3 spd or the HD 3 spd. The first gear is different between them with the HD version being much lower. (LD 2.819 vs. HD 3.714)

There are several gearing variations of T5's, but in general most have a low enough 1st gear that you can figure on starting out in 2nd with almost any rear end.

Rear ends in the stock version were 3.73 or the optional 4.27:1. For practical purposes there are no replacement gears for the stock Spicer 41 rear you have. So you'll need to swap rear ends. In a daily driver, both of the stock options are too low for my preferences. They're great for 0 to 50 mph, but run out of leg room above that.

I can tell you that with the HD 3 spd and a 3.50 ratio 9" rear I can still start out in 2nd gear if I slip the clutch a bit. If I could find a 3.00 - 3.25 I think I'd be happy (this might be too much of a good thing if I had the light duty 3 spd) OR someday I'll put an OD manual tranny in it.

To be more specific we need to know your trans and current rear axle ratio. Either going to higher geared rear end (lower numbers) or using the T5 should get what you're after. Larger wheels will help road speed also. I run 16" wheels for this reason.

 

Sorry I confused you guys. I think that MtFlat has pretty much answered my question. I was thinking that it might be easier and cheaper to change the gears in the rear end. I have a three speed tranny and a stock rear end and I don't know the gaer ratios of either. I don't know if there are any higher gears [lower numbers] available but I thought I would run it by and see what you guys thought. I have heard that 1st and 2nd gears in a t5 were to low when run with a stock rear end.

 

I just installed a T5 and a 9" 3.23 rearend behind my 226 and its just a little hi geared on the hills around here. I think I may possibly go down to 3.50 sometime in the future. My 89 S-10 T-5 has the 3.78 low gear and its not bad at all on takeoff the 226 torque range is awsome. Bottom line is the upgrade is 1000 times better than the 4 speed crashbox and 4.27 rearend. My 51 is so much more fun to drive now I'm really glad I drove it for a year with the stock driveline so I could experience the difference this upgrade has made.

 

this reply is a little late was out of town. My question has been answered it does sound like the T-5 is the way to go. Thanks.

 

Pictures of my T5 install are in my Gallery, If I can answer any questions in the future just let me know.

Rod