jerky trani and loose steering

Tedsoldbus · February 15, 2021, 05:44:25 PM

Bought a 1980 shorty Prevost. In great shape with tight engine etc, but two issues for you old bus guys and gals. I had a 38 foot Allegro bus with 6 speed Allison. I know it was 2003, not 1980, but never felt it shift. This thing ,6V92 with 4 speed Allison is more than jolty/jerky sometimes in the lower 2 gears. Is that normal? Steering is also loose. About 8 inches of turn to get wheel response. Father in law, who drove his 4106 around with Bus Stone and crew many years ago, took a ride with me and says both of those are need adjustment. 3 local Truck service places say they won't touch buses. I live 1 hour north of Atlanta. Ideas??

luvrbus · February 15, 2021, 06:35:31 PM

That is normal for most 740's in the lower range when the torque converter locks up or come out of lockup.the World like you had are a lot smoother shifting

freds · February 15, 2021, 06:42:11 PM

Sounds like your Prevost has been repowered. The normal for 1980 was an 8V71, given that it has be repowered with a 92 who know what the donor power train was. Prevost didn't move to 92 power plants until 82 (I think)..

So you have the 35 Ft version?

luvrbus · February 15, 2021, 06:46:52 PM

Quote from: freds on February 15, 2021, 06:42:11 PM
Sounds like your Prevost has been repowered. The normal for 1980 was an 8V71, given that it has be repowered with a 92 who know what the donor power train was. Prevost didn't move to 92 power plants until 82 (I think)..

So you have the 35 Ft version?

I seem to recall the Foretravel 35 Prevost RV shell conversions were 6v92

chessie4905 · February 16, 2021, 04:39:12 AM

do you have manual or power steering? If power, is there a cylinder hooked to steering linkage underneath with couple of hoses attached to it?

Tedsoldbus · February 16, 2021, 04:45:33 AM

Paperwork shows rebuild in 2000 of the original 6V92. Yes it is a 35 footer. No tag wheel. I will still have it looked at as it just seems to me it feels like the whole drive train takes a shot when it wiggles in and out of lower 2 gears. I live in Blairsville Ga and have called 4 diesel truck places to look at the loose steering and see if maybe shift points can be tweeked on the Allison. Common answer is they all lost money trying to fix bus conversions. Too many things unique to busses they don't have to deal with on the big trucks. Have 2 "bus friendly" places on deck, but they are 2 month out before they can see me. Anyone know the deal with the 35 footers? Guessing Prevost probably only made them one year so so before everyone wanted "bigger"?? I love it. Can still fit in state parks once we get our covid shots and the world seems a better place to travel. Spent a year on the road in 2005 after 25 years in the military. Allegro bus always had something go wrong with it. Slides not coming in or going out. Levelors wouldn't come up. All things I didn't need in an RV to start off with. New ones seem made of sticks, staples and tape, have 5 TV's, and fall apart in the driveway. My father in law had a 4106 for 30 years. He is 90, but still likes to ride in this thing. He hung with Bud Stone and others in the NE when they were starting FMCA. Did meets in farmers fields. No slides, no TV, played guitars while the kids played. OUTSIDE. no cell phones. A different time

Tedsoldbus · February 16, 2021, 04:50:28 AM

Yes to power steering, and previous owner had to have the "safety steering" I think stabilizer bar sent 3 times before the got the right size. Don't know if that would affect it. Entire shaft from steering wheel to gearbox is exposed. I tried the hold each section with vice grip and wife turned wheel a little. U joints seem tight. When the shaft went into the gearbox, I stopped pretending I could fix it. I will do many maintenance things, but Trani and gearbox for steering, I say, nay nay... Man has to know his limitations.

chessie4905 · February 16, 2021, 05:00:42 AM

If the power steering is assist, there is a hydraulic cylinder that moves the linkage instead of it being done by a power steering box itself. If power box, hold the steering shaft right at the box and then wiggle the wheel. Is it fairly tight with almost no play? If like GMC's, there is an angle box at the front corner where steering shaaft changes direction from horizontal to vertical. They can get play there too.

Tedsoldbus · February 16, 2021, 05:31:35 AM

Thanks Chessie. I will stare at that, but probably not touch it. I can get it down the road to the bus guys, but not ready to do the " maybe that fixed it" on steering. My father in law still has 2 surviving buddies from the "Junky old bus" club and he spoke with them on the phone. They both say they could fix it in 20 minutes, but both are 90, moved to south Florida, and don't even have tools anymore. I offered to drive all the way down there and do the work if either of them would supervise over my shoulder, but surprised both said they can't see, can't walk, etc. Made me realize that I have no problems in the world... These 3 guys have pictures of getting together to sand down Bud Stones Flix and then paint it the next weekend. It is the flix used as the logo for FMCA. Made me wish I was born 30 years earlier when they start telling funny stories. But we love this bus and I enjoy solving little issues with it. Retied now and just don't stress over the inverter not working as of 2 days ago. Just have to figure things out.

6805eagleguy · February 16, 2021, 07:50:23 AM

Don't know too much about the 740s, but wouldn't a fluid and filter change help the shifting?

luvrbus · February 16, 2021, 07:57:18 AM

Quote from: 6805eagleguy on February 16, 2021, 07:50:23 AM
Don't know too much about the 740s, but wouldn't a fluid and filter change help the shifting?

Yep changing to 15/40 C rated engine oil for fluid helps

chessie4905 · February 16, 2021, 08:05:52 AM

They were also designed for frequent start and stop cycles with full rated gvw. Trans shifted "firm" to avoid early clutch plate failures.

lostagain · February 16, 2021, 08:33:52 AM

The HT740 is rough shifting in the lower 2 gears. Make sure it is under load when accelerating. Like have your foot to the floor. It will shift smoother. When decelerating, have your foot off the pedal for smoother down shift. The worst is when driving in the city with part throttle that produces harsh shifts. Also shift it manually. I start with the lever in second, so it starts in first and goes to second on it's own. Then shift it up and down the 3 top gears by hand. Again make sure it is under load.

Tedsoldbus · February 16, 2021, 10:34:43 AM

Thanks for jerky trani gouge guys. I have heard some of that from the 90 year olds my Father in law ran with. Told me to quit whining. But will see if it can be tweeked a little. Filters and all fluids were changed just before I got it in November. I was able to mitigate it a bit manually shifting as mentioned, but my little buttercup said "whats wrong" when it shifts. Her dad's 4106 and all the 4104 and Flix guys telling me to quit whining, had "MAN busses!". (They all had manual tranis.) Truck guy told me they made that trani for heavy things like dump trucks, cement trucks, and as mentiond the "jolt" keeps it from wearing out. I can live with it, but Rita was used to the 6 speed in the Allegro. Guess I will have to do most of the driving. (yipee...)

buswarrior · February 16, 2021, 10:54:40 AM

You need an old time bus driver to take it for a spin. Some of it may be the nature of the beast, some of it may be an adjustment.

I am trapped north of the border, anyone else?

Happy coaching!
Buswarrior