I already posted in the axle/tranny forum but no response..... thought maybe one of you guys could help me out. My 85 has a three speed and I''m not sure WHAT tranny it is or what the gear ratios are. It is not an OD tranny so I assume 3rd is 1:1, but I really want to find out what 1st (and 2nd) are. Tranny is bolted on to a I6 -300.

thx.

 

Can't believe I'm having a hard time finding info - here is what I have so far. Tranny is a TREMEC RAB/RAN/RAT ( I think those are 3 different varieties) 85 was the last year in a Ford truck from the factory.

 

well I can find them for most of hte 4, 5, and 6 speeds but not the 3spd trannies guess no one ever figured they were used enough to need to know what the gear ratios were.

 

Not related, but got to drive a 1963 Thunderbird with a 390 and some 3-speed Auto (Cruiseomatic?) with only 50-some thousand miles all original.....talk about a hot number! It just purred out on the highway, and was pretty serious. I loved it. Then got to take a 4-speed/3-transfer tractor around, that was fun too.

 

Thanks for looking.... I was also looking at the AOD, C6, and the T-18. I found all the automatics and manauls at various websites as well as here, but can't find much of anything on the TREMEC 3 speeds.

Mostly I'm thinking about the spare trannys / axles I have and maybe swapping. I have a couple ideas but still trying to evaluate engine, tranny, and rearends so I end up with the right mix of power and economy in each truck.

 

Make one that has a really good power setup, and the other that is a dog for mileage. =)

 

Pretty much... might be able to turn a T-18 from granny low and driving to driving and "overdrive like" economy by changing an AOD with 3.55 rear to a T-18 with a 2.74 rear.

The output on the T-18 is a drive shaft connector and the AOD is splined so I will need to swap out the driveshaft arrangement as well. I dunno yet tho as I haven't looked at all the torque RPH, HP specs to see how well this would work.

I was thinking there would be potential for this plan even though final drive on the T-18 is 1:1 because I could take advantage of the granny low by changing the rear fairly dramatically.

Am I crazy? I figured the engine considerations need to be figured in as well like torque, RPM, etc.....

I'd also like to turn a truck basicallt into a tractor... but I don't have any 4wd trucks ( yet)

 

BTW - I have 3 running trucks that most would consider "junk" so I can afford to play and worse case tear stuff apart and then halfta put it back! Try'n is one way to learn I guess.

 

I just had a thought. Figure the first gear in your 3-on-the-tree is going to be like the 2nd gear in your T18, 2nd gear would be like the 3rd gear, and 4th would be 1:1.

The T18 is a 3-speed with granny low, same with NP435. The ZF 5-speed is a 3 speed with granny low and overdrive. the 3-speed part doesn't change with transmissions, the split is *roughly the same. Now an M5OD is a 4-speed with overdrive, and there are Toploader 4-speed overdrives, basically a 3-speed with an overdrive.

 

I think we're thinking the same thing... the 1:1 of the T-18 acts like OD because I am changing the rear out. I just wanted to get the 3 speed 1st and 2nd gear ratios to match it up with the ratios when you take into consideration the rear ends.... It's all gear ratio x rear ratio and match up to see if they are roughly the same to figure out power diff... then I have to consider differences in engine torque at RPM to guage the feel of the power... or something like that! : )