Engine/Transmission (1994 - 1998) Killer Dowl pin cracked the front gear case

[edgeman]

before i got my 95 cummins the killer dowl pin fell out and cracked the front gear case. The person who fixed it JB welded it and the weld didnt hold up so now the motor is leaking oil like crazy. If someone could tell me how exspensive and hard it will be to fix it that would be helpfull. Thanks.

 

[Joe G.]

Look here: CumminsDatabase.com :: 12V Dowel Pin Repair

 

[edgeman]

thanks very much for the info but does the camshaft have to come out or did they take it out because of the extra damage.

 

[Signal73]

its reccomended you pull the cam instead of trying to heat the gear and pull it off, reinstall can be difficult. Nice time for a cam upgrade also.

 

[Joe G.]

There have been some cam gear failures that occurred later from removing it instead of the whole cam.

 

[WDaniels]

Listen to Joe G and Signal73!!!!! I pulled my gear when I did mine and when I tried to install it, it was a like a monkey intercoursing a football. #@$%!#@$%! I heated the gear to over 450 degrees(too hot) and dry iced the cam and it wouldn't go on more than a third of the way. I finally took the cam back out and took it to the machine shop and had it pressed on. The only reason that they recommend to pull the gear is because it cuts down on the warranty repair time by over 10 hours. Its all about money.

WD

 

[edgeman]

Any idea how much the front gear case will cost.

 

[6BT-Dakota]

Here is a article on Allegedly heating heating up the cam gear before installation. https://www.turbodieselregister.com...-1994-1998/153856-broke-truck-again-pics.html



So be careful ! ! !

 

[JGK]

I pulled the case to repair an oil leak, so replaced the cam at the same time with one from PDR. I spoke to Piers directly about heating the gear to put it on the new cam. I don't remember the exact temp he recommended but he said hit it as close as you can and do so evenly by using an oven. I also put the cam shaft in the freezer while the gear heated.



When the time came to put them together, the gear dropped on with a light clank. No force at all required.



-Jay

 

[6BT-Dakota]

When we did my ATS manifold I had access to a 6BT head that I was able to use to put the manifold together. We heated the center section to about 350 deg. and then bolted it onto the head and the side pieces just slid right in to the center. You have to be quick before it sets up lucky we were.

 

[MCummings]

I'm going to be doing this repair to my truck soon. It is using about a gallong of oil a week.



I'm going to opt on pulling just the cam gear instead of pulling the PDR cam.



I'll let yall know, and will take pics.





Merrick

 

[WDaniels]

Edgeman,

The new case(98. 5 and upward) will cost around 500 smackers. The nice thing about this case is the hole for the KDP is stepped and will not allow the pin to fall back out when it comes loose again. If you want the old case that came on our year trucks, you are out of luck. Was told that only the new ones are left.

WD

 

[MAllen]

Good luck on this, I made this same repair around 6 months ago and it took around 20 hours of labor to do everything. That included taking apart the front end, disassembling the engine front and I did pull the whole cam. There is a method that one of my cummins mechanic friends helped me with where you buy wood dowels and shove them down into the lifters?( the piece that rests on the cam) to hold them in place while you pull the cam and replace it. Let me know if I can help at all. What makes me sick is, if I knew about this website, I could of prevented a KDP incident. Good luck

 

[Joseph Donnelly]

You need a new gear case, Cummins 3936256. It sells for about $250. I had occasion to go into the gear case of a B engine that someone had repaired. Replacing the gear case and heating the gear enough to replace it onto the camshaft without removing the cam from the engine. Two of the three webs between the outer ring with the teeth, and the inner hub, were cracked. The gear should be heated to 325 degrees in an oven. If the camshaft is not cooled but left at room temperature, you will have to drive the gear onto the nose of the camshaft. I put the back end of the camshaft on a wooden block, and use a 3 pound hammer and a steel plate (for the 370 HP marine camshaft that doesn’t go all the way through the marine gear), or a big socket (for regular camshafts and gears)to knock the gear onto the camshaft—it isn’t hard if the gear is preheated and Lubriplate 105 is used. To remove the camshaft, you have to take off the front bumper, radiator, and intercooler. You can swing the air conditioning condenser out of the way usually, so you won’t have to discharge the system. You can make up dowels to hold the “mushroom” style lifters up from 12”+ long ½” diameter wooden dowels with one end chamfered and slit with a hacksaw so they will “spring” and fit tightly into the tops of the lifters. If the camshaft will be out for a while, get a 30”+ long piece of 2” exhaust pipe to replace the camshaft so if a lifter drops off a dowel, it can’t go anywhere. You have to pull the mechanical fuel lift pump out about ½-3/4” so its pushrod will clear the camshaft. You can use a piece of wood to hold it out instead of removing the fuel lines from it. Be sure to spray clean the holes in the block and loctite the gear case bolts

 

[MCummings]

Joe,



How to pull the gear?



I've installed several gears onto cams using the "oven" trick. 40 minutes @ 400*. They slip right on.



I plan to go ahead and pull the intercooler, radiator, and bumper. I've laid the condensor down before with great results.



I have had this leak for several months but I really don't want to pull the cam. I'm prepared to pull the IP, PS/Vacuum pump, fan, water pump, balancer and other misc. parts. The rockers/pushrods cam, etc. I don't want to pull.



Does the oil pump have to come out?



What gaskets to use? I was told there is not a gasket between the block and the gear case. I have used silicone for the last few motors I have built with good results.



Should I put a new front seal? The one on there has about 20k miles.



Anything else I should do while I'm in there?



Should I route the blow-by tube into my downpipe?



Merrick

 

[WDaniels]

Joe,

How do you get the front gear case so cheap? I get a huge discount from the dealers and it still cost me almost 400. I'm gonna have to get you to buy my parts for me. :-laf

WD

 

[Joseph Donnelly]

My local Cummins dealer quoted me their regular price for the gear case at $246. The gear can be pulled with a three jaw (arm) gear puller. I strongly recommend against heating the gear over 350 degrees, and wouldn't try leaving the camshaft in the engine. There is a gasket between the gear case and block, which I install dry; it is Cummins #3938156. The oil pump and water pump do not need to be disturbed. I have re-used the vacuum pump gasket with RTV on it. A new front seal is a good idea. Occasionally you can re-use them if they are fairly new, aren't leaking, and you carefully remove any dirt from the end of the crank before pulling the cover. The cover gasket is 3918673.

 

[MCummings]

ok Big D. I will re-think it over. I just dread dropping a lifter. I've done several cam swaps. It's not too hard, but dropping a lifter is a heartattack maker.



How can I know if I can swap out just the cam or if I have to change lifters too? Is it possible to tell from just looking at the wear patterns on the cam? I would like to move up to something with more flow than the PDR stg1 I have now. I have . 020 shaved off my piston tops, and a . 020 over headgasket, but shaved . 018 off my head to get it back to true... .



Any thoughts? I appreciate the experiance and help.



Merrick

 

[Don Tanklage]

do you happen to know the stock cam specs?



dur @ 050 and max lift?



also curious of the stg I numbers



thanks, don



ps - no prior diesel exp but lots of gas turbo exp and gas turbo motors dont like a lot of cam. either duration or lift. even when converted over to alky (and the compression is inc) they still dont react well to a inc in dur. i do not fully understand this but have just come to know it to be true. really curious what the stock cam numbers are. and if anyone on here knows the ratio of the rocker arms i would love those numbers as well. thanx again

 

[Joseph Donnelly]

To be “almost” certain you won't drop a lifter, use new wooden dowels, chamfered on one end just a little, and with a slot cut with the gain of the wood about ½” deep on the end using a hack saw blade. The front four cylinders are easy to access and the dowels can be longer than 12”. For cylinders 5 and 6 you need to put the end of the dowel into the access hole in the cowl where the rubber plugs have been removed for this job, and rotate the dowel into position to go into the pushrod hole. This process is just the reverse of what you had to do to remove the long rocker stand/head bolt and the pushrod. The dowels should drive into the lifters easily with a hammer, but not pull out easily. I try each one by hand to be sure they are in tight, and hold them up with wooden spring-actuated clothes pins. I pull them out afterwards with a long needle nose pliers and a wood fulcrum for the pliers. I put in a piece of 2” diameter exhaust pipe that is 32-36” long so if one did fall, it couldn't go anywhere and you could drive a dowel back into it. Be careful not to hit the pipe or trough into the soft plug at the back of the cam bore, or it can fall out into the bell housing.



In principle you can tell a lot by the wear pattern on the cam lobes, but I have seen some lifters with pits in the feet. Removing and replacing the lifters is a fairly large, and stressful job. You need a piece of 2” tubing that is cut lengthwise to about 2/3 its diameter, with the open part big enough for a lifter foot to drop in and be pulled out. (Lifter foot diameter went up with the 24 valve engines, and again with the 2003-up engines). You also need a plate welded onto the back end of the trough you just made so a lifter can't fall out the back. Get about 2-3 feet of good string, and tie a plumbing washer on one end that will stick in a lifter tightly enough to hold it, but that can be pulled out by jerking on the string. I use a washer that is about 9/16” diameter, hard rubber, and about ¼” thick, designed for a faucet. Put an 11” long brass sleeve about ¼” diameter on the string. I use nylon “parachute” cord so there isn't a risk of the string breaking. Be sure the knot in the end is out of the way so the lifter will pull up into its bore.



After you remove the camshaft, slide the trough into the block and pull out one dowel. Collect that lifter with a 3' long dowel that has a hook on the end, opened out enough to help grab onto the lifter. The other end of the long dowel will have a hook on it that is tight enough to grab the end of the string with the rubber washer on it. Keep these lifters in order as you remove them. To install the new lifters, push the stopper end of the string through the pushrod hole and lifter bore. With the engine at an angle in the truck, the brass tube helps greatly in getting the string into place. Once the rubber washer is in the trough, pull it and some string out the front of the trough with the tight hook on the long dowel. Push the washer into the top of the new lifter. The cup of the lifter should be dry (you can put cam lube on the end of the pushrod for lubricant later), and the side of the lifter lightly oiled. The foot of the lifter should have cam lube on it, such as Crane and other cam companies offer. Pull the string from the rocker end of the pushrod hole, and lightly bump the lifter with the long dowel to help it turn and go up into its bore. As soon as it is up, rotate the trough so the open side is down. Pull out the washer and string, letting the lifter drop onto the back side of the trough. Drive an 11”-12” wooden dowel into the lifter, and hold it up with a clothes pin. Move on to the next lifter. I suggest doing the lifters at the front (cylinder #1) first as “practice” since the back ones are the most stressful to deal with.