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bronccat's avatar
bronccat
Explorer
Oct 30, 2015

Test Drive Adventure, need advice HR Ambass 36PST

Hi all,

Sorry to come in hot needing help in a hurry but I guess that's this happens sometimes.

We having been working towards the purchase of a 2002 Ambassador 36PST (Cummins 300HP 6BT) for about 3 months

The unit had a leaking head gasket which the dealer finally fixed so I took it about 60 miles down the road to Cummins today to have the engine checked out.

It threw the "code of death" for the injector pump (maxed out at 250 instances in the last 120 hours) but otherwise checked out ok. I plan on requiring the dealer to have this replaced prior to delivery.

BUT.... then this happened.

I thought on the way to Cummins that the unit was struggling on the hills. I don't know the grade but I do know that the level bubble was all the way to the front. The unit lost speed and I ended up with it on the floor. It didn't seem to gear down like I would think it would and then it would surge, miss - something and the warning light would flash once each time. It did this on about every steep hill. Speed would go from 65 approaching to 45 ish at the top (depending on grade / length) - all climbs about a mile say.

Temp was about 200, oil pressure around 60, RPMS about 2000, full boost. A/C was off. RPMs also went down as I climbed.

I tried to downshift using the buttons (Allison 6 speed) but didn't seem to react as I expected so I stopped.

Is this typical behavior? I mean surely the warning light isn't, but is the power where it should be? I know it's hard to say without knowing the grade. I have video if I can post it.

Thanks in advance!
Class A
  • bronccat's avatar
    bronccat
    Explorer
    Oct 30, 2015
    I'll add, I tried the transmission in both economy and regular modes...
  • wolfe10's avatar
    wolfe10
    Explorer
    Oct 30, 2015
    Clearly the Cummins B engine should rev above 2000 RPM, particularly when you used the down arrow to select a lower gear.
  • bronccat's avatar
    bronccat
    Explorer
    Oct 30, 2015
    Yup, exactly. I think the transmission just wasn't downshifting.
  • DSDP_Don's avatar
    DSDP_Don
    Explorer
    Oct 30, 2015
    I'm thinking there are enough obvious issues to start looking for another coach to purchase. If a dealer was REALLY interested in your business and was trustworthy, that coach should have been running perfectly before you test drove it. The list of issues on your test drive could easily run in the thousands. Then you have to hope the thing continues to run well after you purchase it.
  • Gjac's avatar
    Gjac
    Explorer III
    Oct 30, 2015
    What does the MH weight? It may be normal if the MH weights 28k lbs and has 300 HP to move it up a hill. Did the MH not down shift when you tried to shift it manually?
  • Dale_Traveling's avatar
    Dale_Traveling
    Explorer II
    Oct 30, 2015
    Did Cummins find anything else? With the number of power train problems I would be having second thoughts unless the dealer was willing to discount the price, substantially. $10K might be a good no less than number.

    Once you drive the coach off the lot all the risk is on you, the new owner. Unlikely the dealer will offer any type of warranty considering the age of the coach and after market policies will be cost prohibitive.
  • bronccat's avatar
    bronccat
    Explorer
    Oct 30, 2015
    Thanks all.

    26,000 lbs. 4.88 rear end. I could buy it being sluggish but not the surge and warning light.

    As for downshifting, it sure didn't seem like it. I was trying to find a sweet spot by increasing RPMs to maintain speed and when I "thought" I geared down it was like nothing happened.

    They did not find anything else in the scan nor anything in the online history of the ESN.

    So I told them that I couldn't buy it with a clear conscience. Even if they got everything fixed I had no faith in the repairs that they had done to date considering some other issues I found.

    This sucks too because I like these people I vetted them with some people who grew up with them. There aren't many decent dealers anywhere near me who have meaningful Class A inventory and so far they are pretty disappointing.

    Then I look in places like TX and Fl (I am in KY) and I find SO many bad reviews of the dealers. Sigh.

    I'll keep looking. Thanks again!
  • imgoin4it's avatar
    imgoin4it
    Explorer
    Oct 30, 2015
    You do not say what you are accustumed to driving or if this is the first tme you have driven a diesel motor home. The transmission not shifting down when you put the pedal to the metal as expected is not unusual to someone not familiar with how the diesel works, and sounds like my reaction the first time I drove a diesel. The warning lights, the surging and the missing are not normal so there is at least some problem with it. I suggest if you have not driven a diesel before you drive another ( or a couple ) so you have a reference to compare to.
  • bronccat's avatar
    bronccat
    Explorer
    Oct 30, 2015
    Very excellent point that I failed to mention. I have driven a semi, diesel dump trucks and drive a diesel pickup daily, but no - I have not driven a DP motor coach. I knew it would be different than the others but I didn't think this different. Yes, you said exactly what my wife did. First thing I need to do is drive another DP, preferably on that same road.
  • bronccat's avatar
    bronccat
    Explorer
    Oct 30, 2015
    I discovered last night that they have a 2006 DP, same brand, engine, slides, etc. Should be a pretty comparison.

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