School Bus Fleet Magazine Forums
Home | Profile | Register | Active Topics | Members | Search | FAQ
 All Forums
 Professional Garage
 Enter Forum: Professional Garage
 AT545 Rating
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/23/2017 :  10:40:31 AM  Show Profile  Reply with Quote
I was doing a little bit of research looking at some buses and specs. I came across a 1999 BB 3800. It had a GVWR of 27,500. It was also equipped a 210 hp standard torque T444E. That's a pretty high hp engine for a 9 row, although appropriate for the GVWR perhaps.

Interestingly enough, it had an AT545 attached to it. The engine peak torque is rated at 540 ft lbs. Although the 545 is certified up to 235 hp, the max input torque is only 445 ft lbs. This would mean that this engine is grossly overspec'd for a 545 by about 100 lb fts. My question is...why? The bus has tinted windows, a/c, air ride suspension, etc. It surely wasn't for saving money.

I got to thinking about the 6.6 brazilian bus that I used to own. It was the highest rating for a 6.6, 185 hp. I think the peak torque was about 485 ft lbs, which would also put it over the 545 limit.

My only thought is that the peak torque is only obtainable when you drag the engine down to 1600 (or whatever the rpm is for a particular engine). Most 545 equipped diesels seem never to drop below about 1,900 or 2,000 when you drag them down even to a complete stop (only for a second, don't worry). This would mean that you aren't really able to operate the engine near it's peak torque as there is too much "slip/torque multiplication" from the torque converter for the engine to operate in it's peak range. Would this explain why they were able to do mate engines with a much higher than permissible peak torque with a weaker transmission? Or was this just simply poor specifications to save money in years past? I know doing that now would void the warranty and no manufacturer would allow that. To add to that, the 2500 transmissions are pretty much strong enough for most school bus applications anyways. Some of the rear engine units with L series engines probably benefit from a 3000 series transmission.

Keep in mind...when starting from a stop you don't have boost pressure yet, so while you are operating at a momentarily lower rpm, you do not have peak torque due to the lack of boost pressure.

What is the input from all of you guys on this?

Edited by - International-9.0 on 04/23/2017 10:41:27 AM

Thomasbus24
Administrator

USA
4544 Posts

Posted - 04/23/2017 :  12:05:43 PM  Show Profile  Reply with Quote
My vote, despite the other options, it was just to be cheap. No other reason to buy a 545 in my opinion. Others will say they were fine...I replaced too many to agree. 643 please!
Go to Top of Page

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/23/2017 :  12:17:30 PM  Show Profile  Reply with Quote
545s were fine in the gas engines and the lower hp diesels, but they were not designed for high hp/high torque engines. They would have been better if they at least had a locking torque convertor in 3rd/4th like the MTs. That would have saved a ton of heat in the transmission and quite a bit of fuel mileage.

Edited by - International-9.0 on 04/23/2017 12:17:52 PM
Go to Top of Page

bwest
Administrator

United States
3820 Posts

Posted - 04/24/2017 :  04:42:26 AM  Show Profile  Reply with Quote
I have had decent service from my 545s over the years. I have had a few go down on me but they are $400 for a rebuilt. They don't take much time to change out either.

Bryan
Go to Top of Page

Fastback
Top Member

1500 Posts

Posted - 04/24/2017 :  05:05:57 AM  Show Profile  Reply with Quote
According to my book in 1999 the B210 T444e was rated at 485 ft lbs torque, the BH210 was rated at 520 ft lbs torque. I don't believe AT545 transmission was available behind the high torque BH210.

I have not located any documentation yet but my brain seems to remember that the AT545 had a higher torque rating than 445 ft lbs prior to the release of the 2000 series transmission in about 2000-2001.
I do know that we had a lot of conventional buses with 485 ft lb torque engines ahead of AT545 trannys.
I also remember using 15W-40 motor oil in them as per dealer recommendation for longer life.

Why yes, the ORIGinal CHARGER is a Fastback

Edited by - Fastback on 04/24/2017 1:15:03 PM
Go to Top of Page

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/24/2017 :  4:35:54 PM  Show Profile  Reply with Quote
Bryan-Have you actually rebuilt a 545? What all do you do during a rebuild?

Curt-Do you know what the B in B210 means? The emissions sticker on the bus has the hole punched on the B210F. I'm assuming F stands for Federal emissions, as opposed to California. The specs I looked up on the net (and it's never wrong!) show 540 ft lbs. Do you think the buses have less than the trucks or do you think that 485 was all that was available for the 99 models? Perhaps the listed spec was for the 3rd generation 444 models. 99 should be the 2nd gen ones with the split shot injectors. I think around 2001 or so (production date) they went to the 3rd generation, which I think only had small changes.

Do you have more specs from different hp ratings and in different years? If so, could you maybe scan that for me? I really enjoy reading specifications (I'm wierd like that).

Thanks for all your input. This is very interesting to me.

Jonathan
Go to Top of Page

Fastback
Top Member

1500 Posts

Posted - 04/25/2017 :  04:18:37 AM  Show Profile  Reply with Quote
The book I am looking in is not school bus specific and came with our 1999 T444E 210 hp bus (that I speced when ordered new) and covers 1999 and 2000 model year "50 states" engines. The 1999 engines have a "B" prefix and the 2000s a "C" prefix. In 2000 its a "C210" engine and it does show 540 ft lbs of torque.

Why yes, the ORIGinal CHARGER is a Fastback

Edited by - Fastback on 04/25/2017 04:24:32 AM
Go to Top of Page

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/25/2017 :  6:18:51 PM  Show Profile  Reply with Quote
Fastback...you are teaching me so much! I think I figured out the letters. The "A" versions were the original 94-97 engines that did NOT have the split shot injectors. Those had a nice knock to them, but were very slow getting started out. I think the "B" units came out in late 97 or 98 and were the first split shot injector models. I guess somewhere in 2000 they changed to the 3rd generation "C" models. Aside from increased hp/torque, I think there were some wiring harness updates and probably a few other little fixes. I think that the "C" version was the last version of the engine and was used until 2003 when production ended. Has anybody every seen a "D" version before? I don't think that I have. That never made sense to me and now it is all clear. I think the CAT 3126 engines had a similar system. The 3126 was first (but short lived) and then the 3126B version with the split shot injectors came out. I think CAT's "C" version was called the 3126E and this was the final revision before the C7 engines.

Getting back to my previous post...I did have one other thought about the 485 torque value. My service manual does not have any performance data, but it does have a listing of all available horsepowers (for all B and C versions of the engine). It lists a 160, 175, 190, 195 and 210 for the standard torque configuration. It lists a 210, 215, 230 and 250 for the high torque engine family. Since there is an overlap on the 210 hp configuration, I wonder if the 540 is for the high torque engine family? Do you remember if your 2000 models were the 210 standard or high torque versions? Perhaps on the C models the 210 hp was replaced by the 215 and the only the 210 was only a standard torque engine.

Thanks so much for the input. I learn so much on this form!
Go to Top of Page

bwest
Administrator

United States
3820 Posts

Posted - 04/26/2017 :  06:45:17 AM  Show Profile  Reply with Quote
quote:
Originally posted by International-9.0

Bryan-Have you actually rebuilt a 545? What all do you do during a rebuild?





Nope, just order a rebuilt unit. It's been about 3 years since I've gotten one so might have gone up a bit but I wouldn't think much.

Bryan
Go to Top of Page

bwest
Administrator

United States
3820 Posts

Posted - 04/26/2017 :  07:14:03 AM  Show Profile  Reply with Quote
OK, I was WRONG! I know the last one we got was around the $400 mark. However, I just checked on one and they want over $1,800 for them!! That makes it worth more than the bus. lol

Bryan
Go to Top of Page

bwest
Administrator

United States
3820 Posts

Posted - 04/26/2017 :  07:29:20 AM  Show Profile  Reply with Quote
My guy just told me they were about $1,350 about a year ago. It would be interesting to see the "real" reason for the increase. I'll bet it would be eye opening. I may be mistaken on the $400 part because he said he's been there 8 years and they've not been that low. So, either I am remembering incorrectly or I got it somewhere else. lol

Bryan
Go to Top of Page

Thomasbus24
Administrator

USA
4544 Posts

Posted - 04/26/2017 :  08:05:35 AM  Show Profile  Reply with Quote
OK I wondering who's buses your supplier was stealing 545's off of to sell at that price. LOL I gave $1545 for my last one in 2013. That would be a reman.
Go to Top of Page

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/26/2017 :  12:08:30 PM  Show Profile  Reply with Quote
I had no idea a rebuilt was that cheap! I thought a Retran from Allison was about 4-5k, just for the transmission. If you had it installed somewhere, of course there would be labor. How much do you think a Retran MT643 would be?
Go to Top of Page

Thomasbus24
Administrator

USA
4544 Posts

Posted - 04/27/2017 :  04:10:51 AM  Show Profile  Reply with Quote
I'd estimate around $1800-1900 for a 643.

I got an Allison ReTran 2500 in February for $2465. It included speed sensors but not the shifter switch.
Go to Top of Page

International-9.0
Advanced Member

USA
459 Posts

Posted - 04/29/2017 :  11:47:16 AM  Show Profile  Reply with Quote
What do you think typical removal and install labor would cost (if you were sending the job out)? $1000 maybe? I know that varies greatly by shop, but was just curious.
Go to Top of Page

jeeptjken
Senior Member

147 Posts

Posted - 05/01/2017 :  12:11:18 PM  Show Profile  Reply with Quote
just got a 2000 series back from the transmission shop we use it was around 4200 for the rebuild as well as labor

How did you get the gosinta in the whatchamacallit
Go to Top of Page

Thomasbus24
Administrator

USA
4544 Posts

Posted - 05/01/2017 :  12:41:09 PM  Show Profile  Reply with Quote
WW Williams flyer I have says for a conventional with a 2000 series that the installed price out the door is $3685. Includes cooler flush, Transynd and the TCM reset.

While $1220 seems a bargain, I can't justify sending the job out.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
 


School Bus Fleet Magazine Forums © 2022 School Bus Fleet Magazine Go To Top Of Page
This page was generated in 0.12 seconds. Snitz Forums 2000