7 speed transmission to suit Detroit 6V92

[denning]

Here in Melbourne Australia I have an RV. It is a 40 foot Motorhome conversion from a 1979 Denning coach.

It is fitted with a rear mount non-turbo Detroit 6V92 and a 5 speed Fuller (Eaton) crash box. In the 1980's some Dennings were fitted with a 7 speed SPICER model 1372 A crash box. They are very scarce in Australia, so I hope to find one in USA which has come out of a coach with an extension housing for the shifter. Can anyone help?

Alternatively is there a 7 speed SYNCHRO transmission that will bolt with a No 1 bellhousing to the Detroit 6V92. It would need to have an extension housing or be late model with air shift.

I have a friend about to travel to US who could pick up for me. He buys used truck engines/transmissions to ship to Australia. 

[TomC]

I sell Freightliner trucks here in the U.S.  As far as I know, there wasn't a 7 spd synchro ever made by either Spicer or Eaton.  Eaton does still make a 6 spd fully synchro with over drive up to 860lb/ft torque (1,160N/M) that would work on any 6V-92 with up to 80 injectors.  I think you'll find the 6spd to have enough gears for what you want to do.  Good Luck, TomC

[Aussiecoach]

Hi Denning

I'll give you a good ol Aussie welcome.

They may not be able to help with the Box, but the people on this board supply so much good info your Brain will explode.

Wish we had enough Bus Nuts here in Oz to have a Board like this.

I've got a Denning Landseer with 6V92T and 6speed O/Drive spicer...Guess you know there is a few 6speeds around

Cheerz
Glen

[luvrbus]

The few buses I seen here with a 7 speed synchro the transmissions were ZF very hard to find parts or the transmissions  in the US, I am looking for 7 speed ZF for a friend for his bus so far no luck and fwiw his is behind a 6V53 in a 04 Eagle 


good luck

[denning]

Hi TomC. Thanks for your reply. It would appear that you are the "font of all knowledge" about Detroits, as I've seen your replys on other posts. I'm sure I will have more questions for you in the future. Great to know that there are guys like you around. If at a later stage I upgrade to a 6V92 Turbo  whether it be TA, TT or a DDEC, (aprox 350 hp) that Eaton you mention may not take the power (torque)? plus since it is overdrive I'd need to change my diff. Hope someone knows where there is a Spicer 1372 A. Without the power of a turbo I really need to stay in the power band all the time on hills, that's why I need more (7) ratios.

Hi Aussiecoach. Thanks for the "Aussie welcome". You're right, our American "bus brothers' are so helpful on this board. Like you I wish we had one like this in Australia. As for vehicles, mine is a 40 ft 1979 Mono that many owners ago the tag axle was removed. Mostly 35 ft with a single rear axle. I know there are heaps of 6 speed Spicers around, but if I had an overdrive like yours I'd have to change my diff which is 4.11. I love the shape of Landseers, and ride. Maybe one day....

Hi Luvrbus. I had heard that ZF transmissions were the go, but here in Australia they're scarce too. Many friends tell me to put an Allison in it, but I like changing gears, even if I have to be carefull not having synchros.

Will post photos in "Members photo section" soon.

[TomC]

Denning- something to consider.  All the 2 stroke Detroit turbo engines, when you use a smaller injector then the "performance" injector, the peak torque is produced at 1200rpm.  Hence if you do change out to a turbo engine, use 80 injectors for 300hp and 900lb/ft torque. I realize that's a bit above the 860lb/ft torque of the transmission's rating, but-buses are relatively light compared to a truck and how often is it that you're flooring the accelerator (problem lies when the engine is fully powered in 1st or 2nd)?  Plus, use a good trans cooler with it just in case.  With the combination of the 80 injector 6V-92TA producing torque all the way down to 1200 rpm, and the ease at which the Eaton 6spd overdrive syncro trans shifts, I would stay with the 6 spd Eaton and not get too crazy with the other transmission choices.  Especially in Australia that doesn't have nearly the mountains that us Yanks have.  Good Luck, TomC

[denning]

Thanks Tom. My diff is 4.11. I'm sure i'll have to change that if I fit an overdrive box? Do you know the model number of this Eaton transmission?

[TomC]

The 6spd overdrive (only) Eaton's model number is- FSO-8406A.  The gear ratios are- 1st- 7.05, 2nd- 4.13, 3rd- 2.52, 4th- 1.59, 5th- 1.00, 6th- .78.  Based on your 4.11 rear ratio and if you have 12R-22.5 tires that are 485rpm, at 100kph you'll be turning 1606rpm-which is just perfect.  At 1800rpm you'll be at 112kph.  DON'T change the rear end ratio.  Plus-based on a bus weight of 18,000kilos, you're startability with the 6V-92TA will be nearly 20%-of which Freightliner suggests 16% for on road trucks.  Sounds good to me!  Good Luck, TomC

[HB of CJ]

I think it is called a T-14507 and it comes in a close ratio (kinda) direct high gear model; a wide ratio direct high gear model and a wide ratio overdrive.  This tranny (I think) is about as wide and long (and heavy) as the common (US) Fuller 9-speed.

Believe on the overdrive model the gear ratios are around (duhh...) .75, 1.00, 1.37, 2.03, 3,24, 5.38 and around 9.40.....or there-a-bouts.  It is a couple or three inches longer than the 5 speed and a little bit longer than the Fuller 6 speed.

Non synkro.  Anyhow, the plan once was to put one into my planned Crown Supercoach RV plans.  Also you can try a Google search for Fuller Roadranger transmissions and scrow around 'til you find the heavy duty 7 speeds.   HB of CJ (old coot)

[usbusin]

The 7-speed transmission I originally had specified for my Freightliner was a Eaton-Fuller T14607A, non-syncro rated at 1400 lb/ft.

The ratios are 10.50; 6.13; 3.71; 2.51; 1.83; 1.34; 1.00

[Aussiecoach]

Hi

While we are/were talking transmission ratios. Does anyone happen to have access to Spicer info to tell me the ratios of the 1362B (6Sp direct) and the 1463C (6sp O/drive) and are these the exact same size box? Mr Google hasn't helped me much

Thanx
Glen

[TomC]

Most Spicer transmissions are made by TTC transmissions.  They have a good site where you can look up ratios. It appears they only make the 6spd HD in overdrive now.  With the similar dimensions, I would go with the 7 spd Eaton.  Good Luck, TomC

[Mex-Busnut]

Hi and welcome to Denning, from down under.

The Mexican bus we are about to get has a 6V92TA and the 7-speed Spicer 1172-AM standard transmission. I do not know if this is syncro or not, or if it might work for you. I have looked around the web, and found no info on my tranny.

Maybe this will work for you.

Dr. Steve, central old Mexico

[TomC]

Whether it be Spicer or Eaton Roadranger- if it is more then a 6 spd, then it is NOT synchronized.  All American made transmission are the old fashioned non synchroed crash type box that you have to align with the engine speed on each shift.  Good Luck, TomC

[jimsflx]

we have a 7 speed that came out of a 91 eagle 45ft, 102 wide the bus came out of mexico the shift pattern was backwards 1st started on the far right. it was hook to a 8v92 we put a allison 740 in the bus.the 7 speed is in florida if anyone is interested.thNKS JIM