#Th400 transmission manual#

Pictured here is the TCI, 36-element intermediate sprag and drum assembly as used in the TH350. If this is the case, then they are not properly sealing until after a 10-15 minute idle warmup. He went on to say that if a TH350 suffers from this “aging complaint” only when cold, it’s most likely that the lip seals have become too brittle. Larry Speicher in particular mentioned how he has seen countless customers complaining about how their gearbox is “slipping” only to find out that it was suffering from what is known as a “delayed engagement.” This issue is simply the result of a low fluid level or a clogged filter/screen. Occasionally, the TH350 will hesitate on shifts, and this can be caused by a number of things, including a vacuum line leak, a blown modulator, or the bolts on the hold-down plate not being tightened down securely. When it came time to find out what the common formalities are with this transmission, both mentioned the “late shift” issue. The parts to rebuild or repair a TH350 are relatively inexpensive, and since they were offered in everything from family sedans to light-duty pickup trucks during those years, they’re so common that you could still find rebuildable units from your local wrecking yard. I constantly have customers bring me their cars complaining about a slipping transmission, when in all actuality, it’s suffering from what’s known as a delayed engagement.-Larry Speicher Scott Miller and Larry Speicher both agreed that if you build them correctly, they can handle over 700hp. We’ll be describing the pros and cons of each with Scott Miller of TCI, Larry Speicher of Gearstar Perfomance, and J.C Beattie of ATI Performance adding their input along the way. Now before you dismiss this as a tech article that doesn’t concern you, it may come as a surprise as to what can be learned. To clear the air, we sat down with three of the most respected transmission experts in the business, discussed some of the weak points of all three of these transmissions, and found out what it takes to remedy these issues. However, nothing is perfect and everything can be improved upon. Even the late-model LS guys have been seen rocking the classic TH400 on occasion. The most common of those, at least with the older GM cars, is the Turbo-Hydramatic (TH) 350, TH400, and 700R4.Īll three of these gearboxes have earned their stripes over the years, particularly the TH400 as the unit to rely on in a purpose-built drag car. In fact, some of the quickest and most consistent bracket racers rely on a slushbox to achieve their goals.

#Th400 transmission manual#

Scott Miller As fun as it is to slam gears in a manual car, more often than not it’s an automatic that handles shifting duties in drag cars, and street and strip vehicles. I recommend using a high-capacity pan and a transmission cooler for performance-built transmissions.