JTO

I think Zed Head's thinking is correct (as it usually is). With the rubber bushings installed, I have tightened the control arm inner bushing bolts with the rear suspension hanging, then, after lowering the car and driving down the driveway, there was still considerable camber (vertical misalignment) in the rear wheels. You could try this process with the (lubricated) PU bushings and see if the rear wheels are vertical after lowering and driving the vehicle down the block. If the rear wheels straighten up, then the PU bushings are turning in the bushing brackets with the up and down movement of the control arm (assuming everything else is in order). In my experience, when using the rubber OEM bushings, you definitely have to lower the vehicle and put the load on the control arms before torqueing the bushing bolts.

Jonathan...Thanks for your comments. I ended up doing exactly as you described - sanding down the PU bushings (slowly) with a belt sander and bench grinder/sander. The sleeves provided with the PU bushings were the same diameter but longer so I ground those down to the required length as well. The existing sleeves seemed in good condition so I ended up using a new ground down sleeve on one side and a cleaned up existing sleeve on the other side. Apparently, this type of transmission mount cross member was installed on 240Z's manufactured up until July of 1972, then the newer type cross member was used (my 1972 240Z was manufactured in November of 1971). Energy Suspension (and others) only provide a PU bushing kit for the newer type cross member. I also procured a new transmission mount but it was for the newer type cross member as well. I could not find a new transmission mount that fits the older style cross member so I Installed the new mount on my cross member and it seems to work fine.

Ernesto...Good work. Did you road test it yet. I installed the RT Mount with zero clearance between the snubber and the top of the diff nose and found that everything feels very solid, but noisier. It may be less noisy if I had left some clearance between the diff and the snubber. This noise may also be due to the new urethane bushings (as opposed to rubber) I installed for the mustache bar and rear engine mount. In any event, I accept the additional noise for the significant improvements to the drive and rear suspension. I would be interested to hear what you find once you road test it. Tim

Measuring the distance between the bottom of the RT Mount and the top of the diff is the hard part. Your method sounds like it would work. I would be interested to hear how it turns out.

Ernesto...I recently installed an RT Mount but the local guy I bought if from had installed a few of them and knew where to cut the snubber so I didn't have to go through the process of cutting the snubber to fit. If I did, I think I would try the following: With the diff removed, install the RT Mount with snubber. Use something to plumb (like a plumb bob if you have one) to plumb from the middle of the snubber to a spot on the garage floor and mark the spot. Measure and record the height from the bottom of the snubber to the mark on the floor. Remove the RT Mount. Raise the diff on your floor jack, with mustache bar attached, so that mustache bar is in place on its mounts and the diff front cross member and insulator are in position. Install and tighten mustache bar bolts and a couple of the front cross member bolts. Measure the distance between the top of the diff (at the location on the diff that is directly under where the snubber will be...you may be able to identify this location by where there is wear from the old arrestor strap) and the mark on the floor. Using these two measurements, you can then cut the snubber to the required length (either with some clearance between the snubber and the top of the diff, or no clearance). Then lower the diff, install the RT Mount with snubber bolted to it, then reinstall the diff. Measuring from the top of the diff to the floor with the diff in place can be tricky. Before mounting the diff to take the measurement, you can try installing a clamp around the diff in such a manner that you can measure the distance between the top of the diff and "something" on the clamp that will be easier to measure to when the diff is in place, then install the diff with the clamp still clamped and measure from the "something" on the clamp to the mark on the floor. I haven't done this procedure but I think it would be the way I would first try.

Just an update on this. I installed the RT Mount. I now have the diff back in. Everything seems very solid. I am very impressed with this RT Mount. Thanks to all you guys for recommending it. I acquired the RT Mount locally in Calgary so if anyone in the western Canada region is looking for one, let me know and I'll connect you to this guy.

siteunseen...Thanks for your response. I will go back to my Nissan dealership with the old part No. you provided and see what comes up. Can you tell me if your Transmission Mount Cross Member is the same as mine, as shown in the photo, or do you have the newer version, which doesn't have the bar.

I am replacing the Transmission Mount on a 1972 240Z. The attached photo shows the Transmission Mount Cross Member (bushings for each end of the bar have been removed) and two types of insulators. The insulator on the left is the original insulator and the one right is a new after market insulator. The bearing surface of the new insulator (the surface that rests on the bar) is wider than the bearing surface on the original insulator. The new insulator also has a couple of "tack welds" along one edge of the bearing surface. These are visible in the photo. It is my understanding the cross member I have (the one shown in the photo) was used until June of 1972. Beginning in July of 1972, a different cross member was used and that is what the insulator on the right will fit. When referring to "Engine Mounting" in www.carpartsmanual.com the part # for both insulators is 11320-N3000. I am trying to locate a new insulator that will fit my cross member. That's the insulator on the left. My local Nissan dealership advise this older type insulator is NLA. I have searched online but no luck so far. If anyone can help me with any sources, I would appreciate it. If I cannot locate a new "older style" insulator, I may try using the newer type with my cross member and see what happens. If anyone has done this, please let me know how you made out. Sorry for starting "yet another thread" on this topic but I cold not locate a thread where this has been discussed. Datsun Z Engine Mounting (Manual From C-# HLS30-46001, RLS30, GRLS30) L24, L26 (To Nov.-'74).url

Zaspen...Thanks for your response. There are two different sizes of the rubber insulator mount. I will take some pictures and start a new thread on the mount issue .

Zaspen...I am replacing bushings and mounts in a 1972 240Z. I have the same transmission cross member mount as you have in the above thread and the same problem with finding replacement bushings. I ordered bushings and a new insulator mount online but the bushings and insulator are for the larger type cross member and do not fit. Did you use the outer control arm bushings as you described, and did they work. Also, did you change the rubber insulator mount and if so, do you remember where you bought it. When viewing the www.carpartsmanual.com site that Zed Head sent you back in February of 2020, it would seem that the transmission cross member mount (Engine Mounting) configuration changed in July of 72 (which may have been with the beginning of the 73 production).

Zed Head...Thanks for digging up this thread. I will post on that thread as to issues with the Trans mount cross member.

To all that responded, thanks for the info. Much appreciated. On another matter, I had noted in a previous post above that I had purchased the PU bushing kit for the transmission cross member mount from Performance Suspension but the bushing kit they sent doesn't fit. The bushings and sleeves are too long and the bushing diameter is too big. I have attached a photo of my cross member. The distance between the brackets that carry the bar is 2.135". If anyone happens to have a spare cross member sitting around or a cross member out of their car, could you take a measurement between the two brackets and let me know if you get the same or different measurement. I know my cross member is OE but for some reason may be different than most. Thanks...Tim

zKars...Maybe you could send me an email at tim.ogle@shaw.ca. I would be interested in hearing about what 72 240Z parts you have. Jeff G....Thanks for the RT Mount info. I took prints of the photos from the link you sent so now I will get back under the car so I can visualize how it would go in. Ernesto....I agree the torque shouldn't be much different. I will go with the 54 - 69 lbs. Seems like a pretty large range of torque but we will see, Thanks.

grannyknot, zKars...Thanks for your response. Much appreciated. I had a clunk in the rear and what felt like slack in the drivetrain so this is why I am inspecting/changing mounts and bushings. I had previously inspected and replaced bearing cups and spiders for all six UJ's, and replaced all control arm bushings (with rubber). They all still seem good. I cannot detect any issues with the hubs (no noise, no play) or the struts so I am now looking at transmission and differential mounts. The transmission rubber mount and bushings as well as the mustache bar bushings all appear worn (all now 50 years old). The front diff mount looks good as I had changed that in 1997 (21,000 miles ago). I had no problem procuring transmission and diff rubber mounts but the only bushings I was able to locate were urethane so I guess I will go with them (and see how noisy they are). I like the idea of the rubber spacers between the diff and the arrester belt so I will give that a try as well. Thanks for the suggestion. I am still trying to determine how tight the nuts should be for the mustache bar mounting bolts so if you hear of anything, please pass it on. Thanks...Tim

I am new to this site. I have a 1972 240Z. I am replacing some rear suspension/drive train bushings. I removed the transmission mount cross member, the differential front mount cross member and the mustache bar and I am replacing bushings and mounts in these components. I have a couple of questions: I installed new bushings, sleeves and large washers on the mustache bar. What is the torque setting for the mustache bar bolts. I suspect you tighten the nuts until the large washers are fully seated against the bushing sleeves. Is this correct or is there a specific torque? There is an "arrester belt" that straps over the differential housing near the front of the differential. The existing belt showed signs of wear so I replaced the belt. Is the belt meant to fit tight/snug against the top of the diff or is it there more as a guard against the diff coming loose and flying around. The new belt I installed does not fit snug against the top of the diff. I am not sure if the old one did. I ordered new bushings and sleeves (from Energy Suspension) for the small "mustache" bar that mounts in the transmission mount cross member. The bushings and sleeves provided do not fit. Energy Suspension confirmed they are the right parts. I purchased the car new and as the sole owner, I know The transmission cross member is OEM. I purchased the car in Canada and I am wondering if the cross member is different than on a car purchased in the US. So far I have been unable to locate bushings that will fit, or a new bar c/w bushings. Any comments would be appreciated. Thanks.