Haggar

Vinster, That sounds like what you suspect. Slow drain back. For long sits, I bump the starter just enough to energize the pump for the 30 seconds or so. shut it back off and wait 30 seconds or so and start normally. For my brother's truck there were many years(3-5) between the random power losses and the final poor cold start/driveablilty problem. After the poor cold performance (some see it as a poor hot start/hot driveability) we checked closer and swapped ECM PCM (from my truck to his) etc and the problem stayed with his truck. So we shotgunned and changed VP. GL Hag

Vinster, It will drive you nuts. There are so many things it could be. ECM, VP, or it could be like you said, slugs of air, or random limp mode from the map.... My brother's truck did this. Eventually it got worse and eventually cold start/cold driveablilty issues. All without a single code. The VP was the culprit, but extremely hard to diagnose and I don't suggest you just replace yours until you have exhausted other means of diagnosis. GL Hag

Mike, The FRRP does not "dead head". It has an internal regulator that returns the excess flow above which is needed to maintain the set pressure to the inlet of the pump. It works similar to your bigger pump, except it is returned to the inlet of the pump vanes, not going directly back to the tank. Long periods of "dead heading" the outlet from the pump would cause the temperature to rise more quickly in the FRRP than yours because yours would have to heat the whole tank, and this would only have to heat the fluid right around the pump. But we should never run at a dead head situation. (the lift pump is tied to a running motor. an idling motor still has flow both through the injectors and the pump case drain.) Getting closer to the tank is nice. It reduces the NPSH, and with as much fuel as your pump flows, it helps being that close. But as long as your inlet loss is less than the NPSH needed by the pump, there should not be a problem. Hag

Loren, Hook a cheap volt meter up to the pump leads and watch it just like you watch pressure. (make the leads long enough to put it in the cab.) See if there is a change in voltage that would lead you to believe that there should be a corresponding change in pressure. If you have pressure changes without voltage changes, you can more likely assume that something is wrong in the pressure regulating side of the pump and no issue with the ECM. HTH Hag

Jimbo, You don't mention what lift pump you are running and how it is connected. The reason I say this.... I ran into a similar issue not long ago. I still had one of the original o-ring quick connect fittings in the system. This would randomly allow air to enter. I also changed pumps. I do think the pump was allowing air to enter. I still have the old pump hoping to set up a test loop and see if i could catch it sucking air. anyway, since i replaced the pump and that last quick connect, I have not had a problem since. HTH Hag

Keep looking. It sounds suspiciously like a dying VP with no codes. But that is an expensive jump to just throw a part at it. It is very hard to confirm though. is the problem wiring, ECM or VP? You just have to check everything else to death, then decide to replace one of the two components (vp or ecm) if the ECM is booting properly, my money is on the VP. Good luck HTH Hag

Glad you found it! Much easier to repair than the differential! Hag

Dripley is mentioning the "carrier bearing" that is part of our 2 piece drive shaft. The "carrier bearings" that I replaced in my brother's truck are the bearings that support the Ring gear carrier (center section) of the rear differential. (sorry I was not more specific) When you have your cover off to change the fluid, spend a minute looking closely at the gears inside, and pry the carrier, it should not move left to right or up and down at all. I hope you are just having trouble with the clutches sticking. That is the most simple explanation GL HTH Hag

The tag inside of the glove box should say DSA if you have the anti-slip or whatever they call it. DRL is the dana 80 (which you should have) DMD or DMF is 3.54 or 4.11 ratio (you have one or the other) WLA is dual rear wheels (which you should also have) If you do not have DSA on that tag, your truck was not originally equipped, but someone could have swapped rear ends. My brother's truck with just a tick over 100k miles needed carrier bearings. never jumpy or poppy like you are saying, just noisy. I like the idea of just change the fluid. put anti-friction additive in. It will not hurt an open differential, and helps a posi. (some axle fluids come with the additive already in it, because it doesn't hurt an open diff.) HTH Hag

Yeah the manual only talks about the fronts. If I picked the part correctly that is an M14 bolt. (06504691) It looks like it says 10.9 on the head in your picture. The most you should put on it is 120 ft*lb. I would set it at 100/110 and roll. HTH Hag

Wil sorry about that! I wish I had known, I would have sent you to Gould gear & electric. https://www.fixinrams.com/ Their site is not the greatest, but on the phone they can help a lot and get you what you need. Hope your rebuild goes fine! Hag

01 FSM 9-292. I thought it was higher too.

The only reason I mentioned it, was there may be a larger variety of different lockers for you. I thought you were concerned that the locker you wanted was not available in the 70. If the locker you want is available in the 80, it would help your overall picture just to upgrade to an 80 if you can find one. Otherwise, no I wouldn't change to an 80 just for giggles. In the SRW version they are not really that different. just a bit bigger ring and pinion and carrier bearings. Wheel bearings (and we think floater axle diameter) are the same on the 70U and 80 SRW. Hag

Yes, that will give you the "longest" control arm you can have with what you have. (the bolt is pushed in its slot furthest to the rear.) HTH Hag

Ahhh... Castor is in the front axle. The only way to get more or less is to rotate the axle. That is what the cam bolts do. Just take a quick peek and make sure the cam bolts are offset to the rear of the truck (the thicker part of the cam washer to the front of the vehicle.) Death wobble is so weird. It happens so fast, it is hard to determine who started it.... Whose control arms did you use? I noticed a couple vendors selling 14mm bolt diameter lower control arms for our trucks, but 16mm is the correct bolt size. Did you notice anything funny like that when you put yours in? Good luck! I feel your pain. That is not fun!! Hag