Gypsy3000
Junior Member
1st post: all respect to the grey and grizzly!
My first Cummins. Wrenched on many of my prior Ford 6.9/7.3 idi's, P-strokes, etc. Minor Soob expert.
Just bought a '97 2500 4x4, 47re, ext. cab. 350k miles. Price was low due to a very particular shaking problem.
Conditions:
Anyway, needed a tow vehicle, it seemed to drive okay outside of 1600-1800rpms, and the price was essentially half comparable market. Convinced it was trans-related, I bought it and immediately drove it "home" the 600-miles from SF to Baja. Above/below 55mph in OD ran very smooth; no issues & >18mpg. [What is typical City/Hwy mpg's?]
However, yesterday my very-trustworthy local trans shop said that he has owned/driven many 5.9's and he isn't convinced that this is a trans-related problem; he said that compared to others mine is noticeably under-powered and that the throttle response isn't normal. He enlisted a local Cummins specialist to ride-along for a diagnostic test-drive. He, also, was uncertain which system is causing this rpm/throttle-specific violent shaking. The fact that it instantly corrects itself above 1800rpms is confounding to all of us.
Consensus: given that I've already purchased a Goerends 3-disc TC/rebuild kit/shaft & Transgo Shift Kit ($$$), proceed with the trans rebuild and go from there. Regardless whether or not I prematurely misdiagnosed the shaking as a trans problem, given the discounted purchase price and 350k miles there's no harm investing in a rebuilt & upgraded trans.
In anticipation that the shaking problem is neither cured nor diminished by the trans rebuild, I'd appreciate any knowledgeable input:
I know zero about Cummins control systems.
I need a reliable tow vehicle YESTERDAY.
Any qualified input greatly appreciated!!!
Caveat: I commited to this purchase while suffering from undiagnosed covid; very foggy-headed, usually fair judgement downgraded to poor... ("Fully" recovered now, but NOT fun).
My first Cummins. Wrenched on many of my prior Ford 6.9/7.3 idi's, P-strokes, etc. Minor Soob expert.
Just bought a '97 2500 4x4, 47re, ext. cab. 350k miles. Price was low due to a very particular shaking problem.
Conditions:
- Only between 1600-1800 rpm's. Not above, not below (unfortunately, that is smack-center 55mph in O.D.),
- Occurs in all gears but only during low to medium acceleration,
- Does NOT occur at all during WOT, hard-accel, while climbing through gears,
- During WOT, truck seems to accel slowly through 1st & 2nd, but when it shifts into 3rd gear it suddenly has much more accel power.
Anyway, needed a tow vehicle, it seemed to drive okay outside of 1600-1800rpms, and the price was essentially half comparable market. Convinced it was trans-related, I bought it and immediately drove it "home" the 600-miles from SF to Baja. Above/below 55mph in OD ran very smooth; no issues & >18mpg. [What is typical City/Hwy mpg's?]
However, yesterday my very-trustworthy local trans shop said that he has owned/driven many 5.9's and he isn't convinced that this is a trans-related problem; he said that compared to others mine is noticeably under-powered and that the throttle response isn't normal. He enlisted a local Cummins specialist to ride-along for a diagnostic test-drive. He, also, was uncertain which system is causing this rpm/throttle-specific violent shaking. The fact that it instantly corrects itself above 1800rpms is confounding to all of us.
Consensus: given that I've already purchased a Goerends 3-disc TC/rebuild kit/shaft & Transgo Shift Kit ($$$), proceed with the trans rebuild and go from there. Regardless whether or not I prematurely misdiagnosed the shaking as a trans problem, given the discounted purchase price and 350k miles there's no harm investing in a rebuilt & upgraded trans.
In anticipation that the shaking problem is neither cured nor diminished by the trans rebuild, I'd appreciate any knowledgeable input:
- Fuel-system related? Injection pump? I've had to pull/flush entire fuel systems before [WVO-converted Fords, bad-gas sedans, etc]. However, to me this does NOT act fuel-starved = above 1800rpm's runs very smooth,
- At around 1600rpms it abruptly starts bucking HARD then around 1800rpms stops as quickly as it started. Given the distinct effect of throttle-velocity, combined with no GRADUAL vibration increase-decrease, I'm inclined to eliminate driveline suspects: wheel-balancing/rim/tire/front-end/brakes/diffs/bearings (I'll review symptoms of drive-shaft imbalance).
- Harmonic Balancer?
I know zero about Cummins control systems.
I need a reliable tow vehicle YESTERDAY.
Any qualified input greatly appreciated!!!
Caveat: I commited to this purchase while suffering from undiagnosed covid; very foggy-headed, usually fair judgement downgraded to poor... ("Fully" recovered now, but NOT fun).