Shuddering/Bucking when clutching in, loose engine bell housing bolts
This is 3rd or 4th time have had this issue, open to suggestions on solution, and want to alert others to issue. I have a 96 XJ with 5spd and 4.0L, 10 years ago at stop signs it would shudder and buck starting in first gear from a stop. Suspected engine mounts and trans mount but could not find. Then it got hellous and pulled the trans (big job) thinking bad clutch or pilot bearing, they were perfect even though 120K miles on them, but the bell housing bolts were loose, that was the issue. Had it apart so put in new clutch and pilot bearing and put in a TeraLow (which I had invented 5 years before them just did not have means to manufacture them).
Then problem came back, this time so bad the flywheel started scraping that sheet metal thing between engine and bellhousing. If you hear that, means engine and bell housing separating. Anyone else having this problem? The bigger lower bolt on Pssng side that goes blind into block seems stripped, it keeps turning. I have put two nuts on pass through lower bolt on drv side, it seems quite tight was only able to get a half turn more on it. So guessing upper bolts loose or out. Funny thing on this is that it can go away for a month then come back. This time its been on and off for a year, I would check that one bolt (drv lower) and see it was tight and the upper bolts seemed fine. This time think upper bolts are missing. Oh well wanted to pass this on if anyone has shuddering when clutching from a stop. |
Have heard you can use 3/8 x 16 hex head to replace 2 top ebolt. Is that true and if so how long a bolt?
And are there just 4 bolts that hold on the bellhousing, it is so tight in there having trouble finding the bolt heads. |
It's just the 4 bolts that are supporting. There are some smaller bolts that hold the spacer plate (the sheet metal thing) on that have to be accessed from the engine compartment and of course the 3 bolts on the bottom that secure the spacer to the bell housing and the 2 CPS bolts.
I've never had an issue with the engine/tranny connection on either my current 95 or my previous 00 TJ. My Dad had a 94 XJ and never had an issue either. (All in all that's about 710k of manual transmission Jeep I6's). Are you certain you're torquing the bolts to spec? Are the bolts in good condition? Do you have both the alignment pins in place? (Note - my 95 was missing one when I did the clutch a few months ago, I replaced it but didn't have any issues without it.) Are the flywheel bolts torqued correctly? (They need to be replaced if the flywheel is removed per the FSM.) How are your engine mounts and tranny mount? Yes you can replace the inverse Torx (E12 IIRC) bolts with standard hex head bolts. I can't recall the size, but if you take one of the old bolts down to the hardware store you should be able to find the correct size. I replaced mine when I did the clutch. |
If you're having trouble seeing the bolts, lower the jack under the transfer case and look from behind the transfer case (or tranny if you've removed the xfer case or have 2wd). You'll need a good 2.5-3ft of socket extensions to get enough leverage on the suckers to loosen them up (or tighten them in). If you have the luxury of time - spray the heck out of the bolts with PB blaster or liquid wrench and let it sit overnight before removing them. I mangled one of those E-bolts on the TJ and it was a beast to try to drill it out.
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Originally Posted by PatHenry
(Post 3515690)
If you're having trouble seeing the bolts, lower the jack under the transfer case and look from behind the transfer case (or tranny if you've removed the xfer case or have 2wd). You'll need a good 2.5-3ft of socket extensions to get enough leverage on the suckers to loosen them up (or tighten them in). If you have the luxury of time - spray the heck out of the bolts with PB blaster or liquid wrench and let it sit overnight before removing them. I mangled one of those E-bolts on the TJ and it was a beast to try to drill it out.
Yes the aligning pins were in. Its such a bad job pulling the tranny/clutch out, but how can I get snapped off bolt out now without doing that. $1 bolt, $500 labor to replace it. So situation now is 1. Drv bottom have a 3/8" pass thru bolt and nut, seems tight. 2. Bottom Psng have original 7/16" screw into block bolt was tight, but turned it maybe 2/3s turn more using helper bar. This bolt has always been a mystery, It takes maybe 100 pounds torque to turn, but seems to never bottom. 3. Upper psng snapped off in block, 4. Upper Drv think see it, appears to be hex head, but so so hard to see it, not 100% positive it is the Bell to bolt bolt, maybe 90%. My bellhousing looks different than others have seen pics of,, that have two ribs on either side of bolt head (uppers) Mine seems to have just one rib . And the weird symptom of can drive just fine for a couple of months, then bucks and shudders just trying to leave a stop sign. Then drives just fine for months. I do have about 240k on it now and have done a lot of extreme 4wd with near stock XJ 9 (3" LIFT) Just about everything underneath is dented/scraped.. A bit puzzled. |
Yeah, broken bolts are always a PITA.
You'll have to pull the tranny - you can do it yourself, just get a transmission jack (about $130 at Harbor Freight) and once it's off you'll have plenty of room to get a drill in there. I think the main connection of transmission to engine is the two big bolts. They won't bottom out since the threaded part of the block is open. I wonder if you have the wrong bellhousing. I don't remember what mine looked like, so I don't know about the ridges. When it shudders, does it feel like just the tranny is moving or does it feel like the whole engine is moving? If you've done a lot of off-roading, I'd suspect that the motor or tranny mount is bad - have you checked the mounts carefully? I'd use a long prybar or Big Daddy screwdriver to see if the tranny mount is bad and a floor jack with a block of wood under the oil pan to see if the motor mounts are solid. On my 95 with a new Mopar tranny mount there is the slightest of movement (rubber flexing) when prying and if I lift the floor jack with good motor mounts the whole front end will lift with no play in the mount to engine connection. I would suspect that if the mounts are all sound then it could be a worn pressure plate or loose flywheel rather than the mating of the tranny to the engine. You might try removing the tranny mount nuts and putting a jack with a block of wood under the tranny and seeing if the engine and tranny rotate in sync when raising and lowering the jack. If the engine and tranny don't move as if they were a single unit, then the mating is incorrect. |
Originally Posted by PatHenry
(Post 3515833)
Yeah, broken bolts are always a PITA.
You'll have to pull the tranny - you can do it yourself, just get a transmission jack (about $130 at Harbor Freight) and once it's off you'll have plenty of room to get a drill in there. I think the main connection of transmission to engine is the two big bolts. They won't bottom out since the threaded part of the block is open. I wonder if you have the wrong bellhousing. I don't remember what mine looked like, so I don't know about the ridges. When it shudders, does it feel like just the tranny is moving or does it feel like the whole engine is moving? If you've done a lot of off-roading, I'd suspect that the motor or tranny mount is bad - have you checked the mounts carefully? I'd use a long prybar or Big Daddy screwdriver to see if the tranny mount is bad and a floor jack with a block of wood under the oil pan to see if the motor mounts are solid. On my 95 with a new Mopar tranny mount there is the slightest of movement (rubber flexing) when prying and if I lift the floor jack with good motor mounts the whole front end will lift with no play in the mount to engine connection. I would suspect that if the mounts are all sound then it could be a worn pressure plate or loose flywheel rather than the mating of the tranny to the engine. You might try removing the tranny mount nuts and putting a jack with a block of wood under the tranny and seeing if the engine and tranny rotate in sync when raising and lowering the jack. If the engine and tranny don't move as if they were a single unit, then the mating is incorrect. On big right bottom bolt, the no bottoming mean it will never stop turning, so it is somewhat stripped even though it takes about 120 pounds to turn. On Drv side it fell out so did 3/8" passthrough with nut on other side. This has always been a mystery and I worked in auto parts industry for 10 years, grew up in it. My best guess now is it hinging on bottom, top coming back. Eng mounts are polyurethane I put in so no issue there (ah maybe the bolts there loosened?). Back to guess. Most of the time the top is naturally compressed, then something makes it hump up and gap the top of BH, that allows ring gear to scrape the sheet metal cover, and or shuddering. Thinking of putting spacer on trans mount to lift real more and put more compression in top of BH so it does not gap. It clutches normal 99% of time then shudders so bad it hard to get it going 1% of time. I have had friends watch from underneath(to side) trying to figure this out, we never do on shuddering. Another thought, it sheared off a 3/8" bolt at upper Psg location, that takes a lot of force. Next step now trying to tighten the upper drv bolt, if possible. |
maybe some progress. I bought 2 Motor mounts (poly) but it was so hard getting them in as so stiff, only got the drv side in (most important side). The other is orig rubber, it does look loose(rubber).
This explains the shuddering. It's the down side (less force, under compression) Hopefully the poly mount that is in has loosened some after 5 years and it will be easier to get the other one in. On XJ most things are shoehorn. I was able by blind feel to get box end wrench on remaining upper bolt. It seems tight and looks tight. Have a feeling if get the poly motor mount in on psg side the shuddering goes away. Memory coming back, going poly was to attack the shuddering problem and worked for a while just doing the drv side. So do have BH issues and one missing bolt, but if can get the 2nd poly mount in think will cure it. |
Originally Posted by darp
(Post 3516011)
maybe some progress. I bought 2 Motor mounts (poly) but it was so hard getting them in as so stiff, only got the drv side in (most important side). The other is orig rubber, it does look loose(rubber).
This explains the shuddering. It's the down side (less force, under compression) Hopefully the poly mount that is in has loosened some after 5 years and it will be easier to get the other one in. On XJ most things are shoehorn. I was able by blind feel to get box end wrench on remaining upper bolt. It seems tight and looks tight. Have a feeling if get the poly motor mount in on psg side the shuddering goes away. Memory coming back, going poly was to attack the shuddering problem and worked for a while just doing the drv side. So do have BH issues and one missing bolt, but if can get the 2nd poly mount in think will cure it. |
Re: Motor mounts --
Some patience with raising and lowering the jack under the oil pan and the bolt slid right in when I did my pass side motor mount recently. I used a regular rubber mount, but the flexibility of the material shouldn't make much of a difference when trying to get the bolt through - I couldn't move the rubber on the mount at all. I used anti-seize on the bolt to lubricate it, but once I got the engine in the correct position the bolt just slid right in. I had a lot more trouble getting the bolt out than I did getting it back in. Re: Transmission mounting I think that the 3/8 pass through bolt is a concern, despite it being tight. In theory, it's hard to see how the transmission could shift when that alignment sleeve/pin is between the block and bell housing, but I'd still worry about having a smaller than acceptable bolt in there. If the motor mounts don't resolve the issue, I'd consider figuring out how to get a snug bolt in there. (In other words, tap the original threads if they're restorable or drill up to next bigger size, etc.) I still can't fathom how the flywheel could be interfering with the spacer plate without there being a major looseness in the mating or the flywheel mounting being off somehow. |
Originally Posted by PatHenry
(Post 3516103)
Re: Motor mounts --
Some patience with raising and lowering the jack under the oil pan and the bolt slid right in when I did my pass side motor mount recently. I used a regular rubber mount, but the flexibility of the material shouldn't make much of a difference when trying to get the bolt through - I couldn't move the rubber on the mount at all. I used anti-seize on the bolt to lubricate it, but once I got the engine in the correct position the bolt just slid right in. I had a lot more trouble getting the bolt out than I did getting it back in. Re: Transmission mounting I think that the 3/8 pass through bolt is a concern, despite it being tight. In theory, it's hard to see how the transmission could shift when that alignment sleeve/pin is between the block and bell housing, but I'd still worry about having a smaller than acceptable bolt in there. If the motor mounts don't resolve the issue, I'd consider figuring out how to get a snug bolt in there. (In other words, tap the original threads if they're restorable or drill up to next bigger size, etc.) I still can't fathom how the flywheel could be interfering with the spacer plate without there being a major looseness in the mating or the flywheel mounting being off somehow. I can not explain with 3 bolts in and seemingly tight, how that can be, nor why 4th bolt snapped off. On mount It is much harder to get a urethane mount in, trying to drive thru bolt it would not budge, so put back in rubber (think bot new one as so cheap). Here is more mystery, that rubber mount looks just fine on close inspection/comparison to new part pics online. It has a gap on upper 180 degrees, but that is the way they are new. Some people make their own poly mounts, with caulk guns. Am thinking of sealing off both ends then put hole in both, insert gun and fill the gap with polyU and let it set up, maybe half way between polyU, and rubber. Nothing to lose, see if it helps. on 7/16th bottom bolt, thinking same thing, it case torsion is issue. Will try that plus a nut on other side. |
Originally Posted by darp
(Post 3516177)
The whole saga has been a mystery. Yes the first and only other time ring gear hit inspection plate, it was very loose (eng/BH), that is when first discovered the problem 10 years ago. And at that point trans had never been pulled out.
I can not explain with 3 bolts in and seemingly tight, how that can be, nor why 4th bolt snapped off. On mount It is much harder to get a urethane mount in, trying to drive thru bolt it would not budge, so put back in rubber (think bot new one as so cheap). Here is more mystery, that rubber mount looks just fine on close inspection/comparison to new part pics online. It has a gap on upper 180 degrees, but that is the way they are new. Some people make their own poly mounts, with caulk guns. Am thinking of sealing off both ends then put hole in both, insert gun and fill the gap with polyU and let it set up, maybe half way between polyU, and rubber. Nothing to lose, see if it helps. on 7/16th bottom bolt, thinking same thing, it case torsion is issue. Will try that plus a nut on other side. |
I'm a fan of the rubber mounts - unless you're doing really hardcore wheeling, I like the extra cushion of the rubber.
The only way that that upper bolt could have broken off is if someone attempted to remove it and snapped the head off or the shifting of the mating between the tranny and block sheared it off. If the snug lower bolt doesn't correct the issue - I'd pull the tranny off and put a new clutch set in it. It's possible that the pressure plate was installed without cross-torquing and it's warped a bit, or the pilot or TOB is not right. Yes it's a PITA, but certainly is doable with normal DIY tools plus a transmission jack and a good day of wrenching. If you live anywhere near north central MA I'll be happy to help or let you borrow my jack if you do want to pull the tranny. Edit - Just saw NV. |
Originally Posted by PatHenry
(Post 3516181)
I'm a fan of the rubber mounts - unless you're doing really hardcore wheeling, I like the extra cushion of the rubber.
The only way that that upper bolt could have broken off is if someone attempted to remove it and snapped the head off or the shifting of the mating between the tranny and block sheared it off. If the snug lower bolt doesn't correct the issue - I'd pull the tranny off and put a new clutch set in it. It's possible that the pressure plate was installed without cross-torquing and it's warped a bit, or the pilot or TOB is not right. Yes it's a PITA, but certainly is doable with normal DIY tools plus a transmission jack and a good day of wrenching. If you live anywhere near north central MA I'll be happy to help or let you borrow my jack if you do want to pull the tranny. Edit - Just saw NV. Cheers Oh well next step |
I can see 2 things that haven't been addressed.
#1, are you sure the transmission input shaft is not bent? This would cause vibration and tend to loosen the bolts. Add to this wear out the pilot bearing. #2, if it's an aftermarket bellhousing, is the transmission mounting bore perfectly aligned with the center of the engine mounting bolt pattern. |
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