gonecheenin
1/2 ton status
(Warning, Long winded ahead!)
I'm running a '86 3.73 geared one ton dually crew cab 4x4 on 33's for a tow rig
- this thing weighs near 7000lb dead empty and when loaded up with the in bed truck camper, our gear, and pulling the trailer with rig; the old carb'd (JET performance stage 2 Q'jet) 454 has to deal with an almost 18,000lb GCW. FYI: I did upgrade the ignition system, advance timing (think I'm at 8 base and around 38-40 with mechanical and vac all in), replace timing chain, & replace factory mufflers with Flow 40's - but it's stock other than that down to the tubular AIR manifolds for now.
The current TH400 converter stalls too high even empty IMHO and the truck GOBBLES gas even for a big block (6.7 avg empty and about 4-5 avg towing). Running down the road the converter seems to be slipping the whole time as if I'm driving a truck with a CVT trans or something. This truck was at one point in its life (before I bought & fixed it up), a heavily loaded tool box truck for a paving company; so it's not impossible the torque was damaged from heat or something. The paving company guy did tell me the trans was recently rebuilt (Very nice dude that sold it to me, went down to $1100 from the $1500 he was asking; so I doubt he was lying just to make the sale) and judging from the solid shifts and immediate response when manually shifted I believe that it was. However, I have often experienced hydro tranny rebuilds where the torque was overlooked OR the wrong "stock" replacement was used.
I did a stall test in my driveway; at 1100 rpm the truck won't even move on a small incline. At 1/3 throttle it hits approx 1550 rpm and sounds alot like it does pulling out empty. At full 2 barrel it will go 1900 rpm and sounds like it does when pulling out with a trailer, and at WOT it hits 2200 and actually sounds like it's screaming/screeching from the bellhousing area. Running down the road it has plenty of torque even on the hills, but is a pain to maintain speed (like I said, feels like a CVT), it feels like it's constantly revving 2500-3000 grand even on a hill, and even empty it will go from 70 down to 55 on a hill without sounding like it drops much if any of that RPM. With a trailer it's even worse and leaves me basically running full 2 barrel on any small hill and easing into the 4 barrel on big hills (or down shifting to second and pulling the hill with full 2 barrel at 35 mph).
I was originally just going to convert this rig to a standard & be done with this gas sucking auto and it's slipping converter, but after some reflection I decided I'd really like an auto in this particular rig. I'd also like an OD auto with a lockup torque converter that was cheap & reliable. Since that's an oxy moron; I started thinking hard about what I could do to make this current tranny work as good & efficient as possible & that led me to looking into Low Stall converters from companys like Revmax, and Hughes.
So that's where I'm at now, trying to figure out;
A: Should I go with a Low Stall (1000-1200) rpm converter for what I need this truck to do. I will be adding 1 3/4 primary tube headers at the same time in front of the factory exhaust tubing.
B: Will the Low Stall converter improve my overall fuel economy (I'm comparing it to my old standard shift '86 dually's 8-9 mpg empty or towing) and driveability empty or loaded.
C: With the low stall & a full 18,000lb load, will I sometimes need low range just to pull out on a steep hill?
D: Will the low stall still work well once I add the Edelbrock performer intake, Howards MC120031-12 camshaft (.516/.527 valve lift, 215/225 @.050 duration, 112 lobe center), mild peanut port head mods like port cleanup, .040" off the deck (trying to get the .5 point of static compression back that the more aggressive cam will take away), and shim head gaskets.
E: Which of the dozens of companys makes the most cost effective reliable & efficient converter for what I'm trying to do.
Thanks in advance for your time & patience!
I'm running a '86 3.73 geared one ton dually crew cab 4x4 on 33's for a tow rig
- this thing weighs near 7000lb dead empty and when loaded up with the in bed truck camper, our gear, and pulling the trailer with rig; the old carb'd (JET performance stage 2 Q'jet) 454 has to deal with an almost 18,000lb GCW. FYI: I did upgrade the ignition system, advance timing (think I'm at 8 base and around 38-40 with mechanical and vac all in), replace timing chain, & replace factory mufflers with Flow 40's - but it's stock other than that down to the tubular AIR manifolds for now.The current TH400 converter stalls too high even empty IMHO and the truck GOBBLES gas even for a big block (6.7 avg empty and about 4-5 avg towing). Running down the road the converter seems to be slipping the whole time as if I'm driving a truck with a CVT trans or something. This truck was at one point in its life (before I bought & fixed it up), a heavily loaded tool box truck for a paving company; so it's not impossible the torque was damaged from heat or something. The paving company guy did tell me the trans was recently rebuilt (Very nice dude that sold it to me, went down to $1100 from the $1500 he was asking; so I doubt he was lying just to make the sale) and judging from the solid shifts and immediate response when manually shifted I believe that it was. However, I have often experienced hydro tranny rebuilds where the torque was overlooked OR the wrong "stock" replacement was used.
I did a stall test in my driveway; at 1100 rpm the truck won't even move on a small incline. At 1/3 throttle it hits approx 1550 rpm and sounds alot like it does pulling out empty. At full 2 barrel it will go 1900 rpm and sounds like it does when pulling out with a trailer, and at WOT it hits 2200 and actually sounds like it's screaming/screeching from the bellhousing area. Running down the road it has plenty of torque even on the hills, but is a pain to maintain speed (like I said, feels like a CVT), it feels like it's constantly revving 2500-3000 grand even on a hill, and even empty it will go from 70 down to 55 on a hill without sounding like it drops much if any of that RPM. With a trailer it's even worse and leaves me basically running full 2 barrel on any small hill and easing into the 4 barrel on big hills (or down shifting to second and pulling the hill with full 2 barrel at 35 mph).
I was originally just going to convert this rig to a standard & be done with this gas sucking auto and it's slipping converter, but after some reflection I decided I'd really like an auto in this particular rig. I'd also like an OD auto with a lockup torque converter that was cheap & reliable. Since that's an oxy moron; I started thinking hard about what I could do to make this current tranny work as good & efficient as possible & that led me to looking into Low Stall converters from companys like Revmax, and Hughes.
So that's where I'm at now, trying to figure out;
A: Should I go with a Low Stall (1000-1200) rpm converter for what I need this truck to do. I will be adding 1 3/4 primary tube headers at the same time in front of the factory exhaust tubing.
B: Will the Low Stall converter improve my overall fuel economy (I'm comparing it to my old standard shift '86 dually's 8-9 mpg empty or towing) and driveability empty or loaded.
C: With the low stall & a full 18,000lb load, will I sometimes need low range just to pull out on a steep hill?
D: Will the low stall still work well once I add the Edelbrock performer intake, Howards MC120031-12 camshaft (.516/.527 valve lift, 215/225 @.050 duration, 112 lobe center), mild peanut port head mods like port cleanup, .040" off the deck (trying to get the .5 point of static compression back that the more aggressive cam will take away), and shim head gaskets.
E: Which of the dozens of companys makes the most cost effective reliable & efficient converter for what I'm trying to do.
Thanks in advance for your time & patience!
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