ride161

So i picked up an 88 cherokee cheap, $100! It needs a bit of work, but it came with a full borla exhaust and header, a tomken 6" lift (not installed yet) and a rebuilt 4.0 with some work done to it, only 3k on the new motor.

There is quite a knock coming from what i thought was the motor. I did a bit of searching around the forums and then looked to see if the torque converter bolts were loose, which they werent. While under there i looked at the flexplate bolts and they all look uniform with about 1 thread recessed in the crank. Also the flexplate does not appear cracked at all. Long story short, i noticed that if i tried to move the tranny around by hand while the motor was running that the knocking sound would change.

Well, it ends up that there is not a single bolt holding the engine to the bellhousing!!!! Yea, not a 1! from what i can tell, there should be 2 on the top and 2 on the bottom. I looked around the forums and it seems like the correct bolts are m10 for the top bolts and the bottom ones are 3/8 or 7/16. Can anyone confirm this or does anyone have the exact specs for them? lengths and pitch would be awesome! Also, is it necessary to use the inverted torx bolts on the top or can i just use normal hex head bolts.

Thanks for the help in advance!!!

ride161

nobody???

TrekkerJmm

Hi Check your PM's...tj

jeepjerry

They are american thread on the top bolts. I think they used the inverted torx to be able to use a more compact socket since it is very close to the pinchweld from trans tunnel to firewall. My 2" t-case drop made it much easier to reach. You can use hex head bolts though.

This is the same thing that happened on a 89 wrangler i bought....it was knocking and i could see the top of the bellhousing rattling from the engine, it only had the two lower bolts in it.

98 JeepJeep

id be worried about the Engine now....

5-90

Engine should be fine (apart form a little thrust bearing wear,) but the transmission can rapidly seize up from this sort of thing!

The upper screws are 3/8"-16, about 1-1/2" long, and the lower screws aare 7/16"-14, about 1-3/4" to 2" long (sorry, I don't recall specific lengths.) Studs may be used, if desired (I prefer them for manual transmissions. Autos can use them or not.)

For the screws inside the bellhousing (you're going to need this eventually,) the flexplate-to-crankshaft screws are 1/2"-20x.600". ARP makes a kit for Pontiac that works neatly - it includes six pieces 1/2"-20x.590" (I've used this, so I do know it works.) The flexplate-to-torque converter screws are M10-1.5x20m/m, you'll need four of those.

NOTA BENE: The screws that retain the flexplate and the torque converter are not RPT NOT standard hex head capscrews! They are "place bolts," and are actually designed to retain tension under high shear loading due to the head design! The use of a standard hex head capscrew, socket head capscrew, or pretty much any other common hardware store item (of whatever quality) is not RPT not recommended! Make sure that the replacement screws are also "place bolts" - you can check a local tractor supply house (they usually have excellent selections of threaded fasteners,) aeronautical surplus house (if you have one locally) or speed shop (ARP had a good line of screws!) for proper replacements. The use of standard HHCS or SHCS can - and usually will - lead to premature failure. You Have Been Warned...

ride161

thanks for the help everyone!

I got the bolts and installed the lower ones last night and still have the knock. Im hoping to get time to install the uppers this weekend.

5-90, As for the bellhousing internal bolts, when looking thru the inspection hole, all the torque converter bolts are tight, and the flexplate to crank bolts look uniform with about half a thread recessed back from the end of the crank. Also when im under there i dont see any vibration on the crank or flexplate.

Again, thanks for the replies! Ill keep everyone posted.

JeepJerry, im hoping youre right on the top bolts and that it fixes it like yours! but i cant even see the top of the bellhousing to see if its rattling!!!

jeepjerry

You can gain clearance up there by putting a jack under the trans crossmember, unbolting it, and dropping it down. That is if your bolts will come out.

ride161

will do... thanks!