BNO BBS - BNO's Bulletin Board System
TOPICS => THE BOARD => Topic started by: sledhead on October 07, 2013, 03:17:18 PM
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I have been looking for a 5 speed auto for my 6v92ta to replace my ht740 auto I have now . I did have a deal on a ht754 but I could not find the electronics to make it work . So is the mt654 a non elect. transmission and would it be strong enough to handle all that power of the 6v92 ta ddec (350 hp ) I see lots for sale .
thanks dave
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It is non electric and i think it would be fine in a bus application (motorhome) but how much wieght etc are you pulling and where? ie hills mountains, fla beaches etc. The archives will tell you yes and no but there are sure to be specs for that trans. good luck. And where do you see them for sale? Online or the trader papers?
Also check the specs to see if you are getting a true five speed or a four with a low that sort of thing. I think Trans Diesel of Central fla could help 407-295-1221 or email davidf@transdiesel.net Good luck and let us know what you do.
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You don't want a 600 series behind a 6v92 they are not rated for enough hp(250) or torque(640) for the 6v92, the 600 uses a # 2 bellhousing or a drop ring and a different flexplate it has the starter ring on the flexplate where the 740 starter ring is on the torque converter and uses a sae # 1 bell housing forget the 600 series if I remember the 600 series did not have a close ratio only the deep ratio on a 5 speed
If you want a close ratio 4 speed just change the planetary gears in the 740 only part you can change on either the 754 or 740 transmission is the 1:1 final
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The sheet that i have on the MT654CR says it is good up to 300 hp max, and 780 ft. lb. max, and up to 80,000 lbs GVW. Also says it uses a SAE 1 or 2 flywheel housing. Size is L 36.23 in., W 19.25 in., H 21.60 in., and weight is 625 lbs.
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I have seen this unit on mid to late 80's in wonderlodge rv's 6v92 ta with 5 speed mt654 . I have had no problems with my 740 just looking for a 5 speed .
thanks dave
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Still not enough Ed for his 6v92 I never saw 654CR I before saw lots of 654DR came from trash trucks and you can use a SAE 1 bell housing but it requires the drop plate adapter your 5 probably has one mine did both will work since the starter ring is on the flexplate a 740 will not work on a SAE 2 bell housing how ever
Dave the BB had a de tuned 6v92 in that era that is why they were red in color I have changed those over to the silver rating before
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Clifford, i don't have the 654, i have the 644 in my 5, the 644 is 6 in. shorter than the 654. :)
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I have a 5 speed in my 5A. I was told it was a 6?? whatever by an Allison mechanic. I think he said that it was popular in trash trucks. I think he said 654 model. I have what should be a 350 HP 6V92. 9G90 injectors and Turbo set up for the 350 HP. I must have something besides the injector/turbo set up making HP. Advance timing ? maybe. I know that the Allison man couldn't believe how my bus accelerates. My cooling needs are unreal. I have doubled the rads and still have trouble. (everything else is as it should be). Anyway I drive it pedal on the floor whenever possible. Mostly towing a car or trailer. Damn this thing moves... Even @ 10,000' plus I can climb a 5% or 6% grade @ 50 + MPH.We have put over 40K and previous mileage unknown. I was advised not to open the trans up as many parts are unobtainium. Maybe I'm on borowed time but it has worked for us.
Don & Sheila
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92 series are not A timed with those injectors fwiw,that is a strange setup the 700 series will fit a Mci 5 with a 6v92 the C had a 740 behind the 6v71
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92 series are not A timed with those injectors fwiw,that is a strange setup the 700 series will fit a Mci 5 with a 6v92 the C had a 740 behind the 6v71
When I bought it, it had 9200 injectors. It's not low gearing. It tops out about 100 mph. @ 75 I think it's @ 2050 rpm. Governed @ 2350. I'm usually towing approx. 3500# and the bus weighs in @ 10,000# front and 17, 000# rear axle. Judging from the answers on the ratings of the 6?? trans maybe I should be looking for a pre-emptive replacement...
Don & Sheila
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It's probably a old 60 or 70 that had the overdrive all I can tell you about the 9g90 injectors is the timing is built in the injectors install those in A timed engines they are junk
The 9200 work with A timed engine your 6v92 was probably around 380 to 400 hp with the 9200 injectors with plenty of smoke
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After looking up the specs on the mt 654 cr
mt 654 cr ht 740
1st 4.17 1st 3.69
2nd 2.21 2nd 2.02
3rd 1.66 3rd 1.38
4th 1.27 4th 1.00
5th 1.00
I like the idea of not having the electronics in the trans as I have had no luck finding any for the ht754 trans. Is there a ht 5 speed cr trans. out there with no electronics like the ht 740 ? I have seen a lot of the mt 654cr on the internet for sale , it looks like it was made into the late 1990's thanks dave
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For the amount of work necessary to convert to the MT654CR, and the fact you'll have to derate the 6V-92TA down to 780lb/ft torque, I'd keep the unbelievably reliable and super strong HT740 (it is the transmission that's used in just about every hot rod Diesel truck). Instead, I'd soup up the 6V-92TA. Jay Leno has a specially prepared (by Valley Detroit Diesel) 6V-92TA DDEC in his Flx that puts out 435hp and 1350lb/ft torque. You'll find out the hard way that the 5spd just isn't going to make that much difference in your speed up the hill (maybe 2-3mph). What gets you up the hill is raw torque. Upping your engine torque from the 1,000lb/ft to 1350lb/ft-that will get you a noticeable increase in up hill performance. Good Luck, TomC
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Isn't it true that the more HP you get from an engine the shorter the life of it. Something has to give.
Bill
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I don't think Jay owns that bus I think his mechanic does.
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I would sure like to see a photo of the 745CR electronic transmission since you have been posting about it I have gone through every Allison manual I own and cannot find a 754CR electronic either by WT,ATEC and CEC (commercial electonic control) those are the only 3 electronic controls I know of Allison ever using
That has to be a conversion by someone according to the serial # you posted it shows it to be a HT that is a rare bird indeed
The HT754CR should not be that hard to find,but if you go with a 600 series from the 700 series you have your work cut out for you plus the $$$ it will cost for parts
good luck
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The Allison MTB654 with Retarder was used with the 6V-92, proved to be very successful in RV Coach service.
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Engines are funny when it comes to developing HP and torque. Obviously both are related, and HP is derived from the torque measurement at an RPM, but I know from my experience dynoing race engines that to get an engine to develop it's maximum torque at any given RPM you have to stall it out - give it a load such that it is at a steady state engine speed at full power (dyno operators can cheat and increase the load to actually decelerate the engine, but then you are measuring the dyno's torque capacity, not the engine's). If the engine can accelerate, it has insufficient load to develop full torque and so some of it's power is going towards accelerating the engine speed rather than out the back to the transmission. That's why transmissions with lower ratings survive so well with big power engines in light vehicles. The 350 hp 6V92 with the 6 series gearbox in an MC-5 is going to accelerate pretty hard in almost any situation, and on a hill it will be running at a higher RPM than the peak torque speed, since it develops a lot more HP with the increased engine speed and HP is what actually does the work. So you get to push the envelope a lot more than you would with a heavy truck that might be working the engine to it's maximum and actually developing that big torque number with far greater frequency and duration than a bus application would.
Brian
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This early in the morning you made my brain hurt......i think i need my second cup of coffee before i re-read this. :)
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I called about the ht754cr (deal ) today to see if they had made any progress with the electronics to work with my 6v92ta ddec 2 . As this is over my pay grade . As I see it the electronics are only there so the eng. ddec can talk with the trans.and for the push button shifter is this right ? With my ht740 now I have the cable shifter but there is still a connection from the trans. to the ddec right ?
thanks again dave
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The electronic modulator is all that is required for a 740 to work behind a DDEC engine
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The HT 754 is not an electronically controlled transmission; no shift pad. As Clifford said, to put a hydraulically controlled transmission behind an electronically controlled engine (DDEC, Cummins, etc) you just need an electronic modulator. Allison Transmission puts out bulletins called Allison Watch. There is an Allison Watch bulletin that deals with installing an electronic modulator. If anyone needs a copy of the Watch for this let me know. I got into this back in the 90's when I put a 740 behind an N14 525.
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Thanks Boomer if you could find the bulletin and send me a copy that would be great . It would be nice to have the extra gear between 3rd and 4th .
thanks dave
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Who tells you the 754CR is a electronic transmission I have told you since day 1 they were never made check your 740 behind the DDEC on the passengers side above the oil pan on the transmission you will see the electronic modulator with 2 wires that is all that is needed for the 754 to work for you either use that modulator it will work or buy a new one for 150 bucks
good luck
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Well hears the latest ! I copied and pasted then sent a copy of what boomer had said via fax to the shop that has the 754cr transmission , then called . I was told that the trans. has a 30 wire connector on it so I guess that is for the push button shifter that came with it ? Any way I told them if they find a way to make it work to call me . So looks like my 740 will have to do and with the up grade to 350 hp + the propane injection I will see how the trip south go's later this year . Thanks Cliff , Boomer and the rest of you guys for all the help . dave
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Dave
Could it be that it is a 755cr ??
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You beat me to it Joe the 30 pin J1A,J1B and J3 is a shift selector connector for a 755 Allison
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Yep, probably no tag on the trans and the shop doesn't know what they have.
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Ya I think you guys are right . I was originally told it was a ht755cr but some how the s/n I got is for a ht754cr ? dave
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They both use the same case only a different valve body somebody could have used the 754 case and never tagged it,the serial number you gave is diffidently a 754
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Dave
Would appreciate a phone call over the weekend.
Joe.
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Joe I will call you on sat thanks dave