I will be getting a 1987 TII with a bad rear differential mound and wondering what affects it has on the car and how to replace it, is there precautions i should take driving it, im traveling about 400 miles to get it and wondering if it will make it back, Please help.

 

I saw a pic of a huge U bolt that a guy used to hold down the diff when he kept breaking mounts I think it was a 6" U bolt over the top of the diff and a steel plate going under the subframe it was pretty ghetto but it would solve the problem for a moderat drive. If not just drive it like a grandma low rpm easy into the gas run as much highway as possible and you should be fine.

 

here is a link to that thread

https://www.rx7club.com/showthread.p...erential+Ubolt

 

is it a easy process to replace this?

 

It's a mount, not a mound.

Unless you;re really mixtreating the car you won't be doing any more damage, it'll just be really annoying (thunk, thunk...).

In a workshop with the car on a hoist, with another person, yes. On your own in your garage with the car on axle stands, no...

 

as NZConvertible said, you won't do any damage, but it'll really sound like you are. just engage and disengage the clutch with a little slip each time to avoid making the sound.

even though it's a bit of a chore to replace it w/o a lift it's worth doing as soon as you have a day to kill. i drove mine for a few months with a busted mount and even after i replaced it it took me a few weeks to get used to shifting correctly again. so replace it if you want to avoid developing bad shifting habits.

also, in all likelihood, what you're talking about is a front differential mount (the diff has two rear mounts and a front) so do a search for that. there are about three or four threads that will help out a lot. be sure to get the fsm diagram for the rear subframe as it'll tell you exactly which bolts you need to remove. it's a good first project for an fc owner.

 

it's mistreating not mixtreating

but as nz said, if done in your own garage it wont be easy. i've driven my fc with a busted diff mount for 2 yrs and i really didnt have a problem besides the annoying thunk. so i fixed it with a solid mount and it's fine now. if you're planning to fix it yourself, be prepared to have a really good workout.

 

well he says its the back, maybe hes wrong but thats all i kno, i havent looked at it, but it does sound like a fun project, thanks for your help, now atleast i kno i can bring it back in one peice, but is it possible to have only 1 bad rear diff mount? sorry about these stupid questions, im new to this rx 7 thing, i cant say i kno a lot just a little bit, but im hoping to learn.

 

some people mistakenly refer to what is the front mount on the differential as the "rear differential mount", referring to the fact that it's the mount on the rear differential. buy since there's only one diff, it's the "front differential mount" in contrast to the rear mounts.

it's definitely possible but not as likely that he means one or both of the rear mounts on the diff. if it's the front mount, it'll clunk loudly. i don't know firsthand what it's like with bad rear mounts, but i'm sure the effect isn't as pronounced. ask the seller what it sounds like to engage or disengage the clutch. some people also describe it as a "pop".

the difference is that if it's the front mount, you just have to lower the subframe, but if it's one or both of the rears you'll need to remove it entirely. even if it is just one rear mount, though, they're sold in pairs so you'll replace both anyway. get the fsm diagram of the subframe (link is in the FAQ) so you can see what i'm talking about.

 

well if someone can help me, im going to pick this car up, would it be better to drive it slow all the way, or hook it on a tow thing where the back wheels are dragging or would that do more damage, it is about a 400 mile trip, need help on this, trying to go out on saturday but not sure how to bring it back

 

RWD = tow from rear only front should be on the ground
FWD = tow from front only rear should be on the ground

you can tow a RWD from the front however you would have to disconect the driveline first.

and a good rule is a a used car you dont know that has some "issues" should be towed if and whenever possible, why risk breaking down and possibly costing you more money?. thats a pretty long tirp but it your choice, just make it a smart one.

 

im not sure how to dissconnect that, i will search it but any help would be nice, is it a quick thing?

 

Sorry I have never done it on an FC only my first gen. but I would think it to be more trouble than its worth, why not just load it on a tow dolly correctly? is there some reason you would not be able to?

note: tow dollys are cheap to rent and easy to use, you may even be able to get a small flat bed trailer used strictly for moving cars.

I dont know whats in youre area but around here I just call the local U-Hual.

 

well thats sounds good, i have a uhaul place in my back yard so i will let you kno how that goes

 

not to thread jack but i figured this would be better than making a thread. but, where can i get a diff mount. i need one i hate that clunk when shifting gears. but thanks ppl

 

mazda, i think mazdatrix, and racing beat. try ebay too

 

you don't have to drive it slow, just engage and disengage the clutch a bit slower than normal. you can drive at regular speeds. i drove mine all over half of my state at all different speeds for six months before i had the time to replace it. there's no need to tow it.

 

You can also back the RWD car onto the tow dolly and use a bungie cord to secure the steering wheel into a straight ahead direction. Always leave the key in the ignition and turned on so that the steering column will not lock up.

I towed a car from Kansas City to Dallas this way and several cars shorter distances. Works like a charm.

 

Al lthis talk of towing is irrelevant. There is no reason not to drive the car with a broken fron diff mount. All it will do is make a bit of noise occasionally. That's all!

 

^ that was not even the point, no one said the car could not be driven with the broken mount.

The OP is buying a 19 year old car he most likely knows very little about. (that may be an assumption however nothing has been said to suggest otherwise) he is faced with driving this car 400 miles home and it already has a broken mount on it who knows what else is possibly wrong with the car. maybe nothing at all but why take the risk of breaking down so far from home when there is other options. its just common sense till someone with knowledge can asses the safety of the car and its drivability.

again its just a friendly suggestion, not once was it said he could not drive it. (would any of you want/let your kid buy and drive an old used car without it being safetied first? I doubt it.)

 

well i went the 400 miles to get the car and it drove the whole 400 miles back, i was slow on the clutch and it made softer clunk, it has a close power steering leak( crack in the hose), a slow oit leak, bad AC pump, no air duct, and can use some new exhaust gaskets, and i talked to the guy a good week before i went down and took a friend who knows more about rx-7 than me to check it out, but it is home with no problems and made it all the way, and i am now the proud owner of my first car, a 1987 TII, a little bit of work, but not a whole lot, im wondering if anyone has a front rear differential mount for this car, if so please get pm me, or if you know where to get one, that would help to.

 

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Where in In do you live?

 

http://www.teamfc3s.org/main/factory...REAR_AXLES.pdf

page 9-24 is what i used to change mine. it's the block right next to #6. do a search for "front differential mount," some threads are more detailed, find these.