Spicer swap to Auto

[fireboltjoel03]

Hello folks I'm joel a newb here with  a 1969 Silver Eagle.

Want some advice on doing a swap from the Spicer manual to an automatic. My research has found that there a lot of different versions of the Allison HT740.

I would like to find a 740 with a retarder. Does anyone know which Ht740 version has a retarder?

If there is a different auto that'll work with the 8v71 that's recommended please share.

oh and I'm in the mountains of Montana in case that makes a difference.

thanks
Joel

[luvrbus]

You don't want a 740 with a retarder they put to much heat back in to the engine cooling system, some try air to oll cooler they don't seem to work that great on Eagles,the double water to oil coolers seems the best way to go,the 740 works fine on a Eagle, plenty of room for 1 but does take some moving of the tubes to clear 1 area. Jake brakes are the best way to go,a 1/2 set works ok,the passenger's side for Jakes takes a rerouting of the air system on the Eagle and can cost several hundred of dollars for the 4 rubber bends and pipe,The 740 with a retarder is identified as a 740R getting the controls to the drivers area for the retarder on a Eagle can be a experience by it's self ,your bus is a 05 right       

[fireboltjoel03]

Thanks so much for the education.

yes the bus is a model 05. So you're saying to add a Jake brake to the 8v71 is the best way to go?

And what about the different HT740s, is there a preferred version for my bus?

Is the HT740D a good fit? Found one at a pretty good deal.

thanks
joel

[luvrbus]

The 740D is a later updated 740 they are great transmissions ,all the 740's are the same demission's ,you may have trouble finding the center hub for the 8v71 for the flex plate they are getting hard to find now, flex plates are easy  the 6v92 and 8v92 use the same flex plate just a different center hub

[fireboltjoel03]

Do I need to be concerned about the transmission gearing or are they all about the same?

thanks
Joel

[luvrbus]

The 740 is 1:1 Eagle didn't offer different gearing for the 740  Eagle, only used the 3:36 or the 3:73 for both,I think the Spicer had little OD in 4th, the 740 works the best with the 3:36 living in the mountains the 3:73 works good you just loose about 1 mile to gal either will work ,the 3:73 was the gear behind all the 8v71 engines in Eagles