Date: Fri, 11 Jun 1999 05:25:19 -0700 (PDT)
From: David Edge
Subject: [imps] Gearbox help
I have had a minor problem with my gearbox ever since I bought it from a gentleman who informed me that his dad bought it brand new for his imp having covered only 3000 miles in it since - CRAP.
The box is / was knackered, basically it has always had a tendancy to jump out of 2nd gear when very hot.
This would only happen once in a long journey so it never really bothered me. Last night on the way back to Bristol from meeting Tim on the M4, it jumped out of 1st gear when driving out into a main road with such a crash I thought the world had ended. Now it drives fine but everytime I put it in 1st gear it just jumps straight out again.
I can nolonger drive in 1st gear, I can manage for quite a while like this but I need to sort it out soon...
I have also have a rally gearbox with lowered 4th that is a bit rushed for motorways, its only complaint is a rumbling input shaft.
Question is can I put something together from both mk2 boxes, i.e. 1st and 2nd from the rally box (they have brand new synchros) and 3rd and 4th from my std box complete with the input shaft and bearing from the std box?
HELP
Date: Fri, 11 Jun 1999 05:26:45 -0700 (PDT)
From: David Edge
Subject: Re: [imps] Gearbox help
Whilst I am on the subject, does anyone have a spare rumbling rattling no top gear(or similarly fatally dead) transaxle that I can use whilst I mend the ones I have got.
From: Reijo Halonen
Date: Fri, 11 Jun 1999 15:50:15 +0200
Subject: [imps] Asia: [imps] Gearbox help
You are not alone with gear box troubles. I am racing with Imp Rallye in Finnish Historic Race serie and in last weekends race i lost the 4th. gear. It just disappeared without any warning.
I have't opened the box yet but i am afraid to need a new 4th. gear ratio. As you mentioned to have a rallye gearbox with lower 3th. and 4th. which you maybe not need please inform if you are willing to sell them.
Date: Fri, 11 Jun 1999 15:09:02 +0100
From: Andrew W. MacFadyen
Subject: Re: [imps] Gearbox help
before you take the engine and box out
- Take the detent ball out the seletor shaft and stretch the spring.
- Make sure the gear linkage is correctly centered -- very often Imps jump out of second because the linkage runs out of movement and is not allowing the gear to be full enaged -- if you look at the base ball joint of the lever you will see what I mean.
Date: Fri, 11 Jun 1999 07:28:42 -0700 (PDT)
From: David Edge
Subject: Re: [imps] Gearbox help
I have ruled the detent spring out of this equation, although it may have caused the intial problem and allowed it to jump out of gear in the first place, problem is that it jumps out of 1st so viciously that no amount of detent spring will help.
From: Nickcleak@aol.com
Date: Sat, 12 Jun 1999 03:52:57 EDT
Subject: Re: [imps] Gearbox help
perhaps one of the 2 nuts on the end of the shafts has come loose and is giving endfloat ..
i did manage to press off the lower 4th gear from the input shaft , and press on a standard one . i couldn't live with 5000 rpm at 60 mph for more than a week .
the raised 1st is very worthwhile though ..
From: Allan Duncan
Date: Sat, 12 Jun 1999 23:45:55 +1000 (est)
Subject: Re: [imps] Gearbox help
> perhaps one of the 2 nuts on the end of the shafts has come loose
> and is giving endfloat ..
The sudden change in behaviour is worrying. It might be a broken shift plate, but I have always had that happen on 3rd. (If the spacers aren't just right, the outer hub slides too far over 4th, a plate lifts up too high, catches, and is snapped in two when you slide the hub back to neutral. This is also likely to happen while the rear cover is off during final assembly and the travel of 3rd/4th selector not limited.)
If it isn't the loose nut (and it would need to be the output shaft one), then consider the syncro hubs themselves. I have three boxes, and have played around with one that jumped out of 2nd on the over-run. Re-arranging the inner and outer relationship cured it totally. Someone had presumably pulled it apart and reassembled differently to original. I think that the wear pattern affects it.
I did the reverse to another box, but can't get it back to the correct alignment - it is better but not perfect.
As to the original query - if the hubs are the same, switch them, but mark the parts in case they fall about.
Of course, all the above is based on the original style units. Don't know about the later ones, but I suspect the same - they all have splines that wear asymmetrically. I seem to remember a picture showing the two parts held together with bulldog clips for safety.
Date: Sun, 13 Jun 1999 15:32:45 -0700 (PDT)
From: Si Trickett
Subject: Re: [imps] Gearbox help
If the gearbox thing gets you down always remeber the gearbox part called 'Muff Coupling'
This still makes my mate steve and i laugh
Date: Tue, 22 Jun 1999 01:08:06 -0700 (PDT)
From: David Edge
Subject: Re: [imps] Gearbox help
Rich informs me that a Muff Coupling is quite often used under water on such things as oil rigs - you know what that means, you guessed it, the guys who fix these couplings are muff divers... > If the gearbox thing gets you down always remeber > the gearbox part called 'Muff Coupling'
Date: Tue, 22 Jun 1999 01:12:22 -0700 (PDT)
From: David Edge
Subject: Re: [imps] Gearbox help
The gearbox saga continues, I have decided to build the rally box up again, having stripped it I discovered that the input shaft bearing was absolutely shot to bits, I am using the piece(2) of casing from my dead std box as it has an excellent input bearing.
I now have a couple more questions:BTW, the old std box (the one without 1st gear) has a lot of metal filings spattered around 1st gear, I shall investigate for a laugh later.
- Are there any considerations when rebuilding a gearbox other than specified in the Haynes manual.
- Has anyone tried to make the tool to tighten the main shaft reverse gear to the correct torque.
From: Nick
Date: Tue, 22 Jun 1999 16:17:38 EDT
Subject: Re: [imps] Gearbox help
> I am using the piece(2) of casing from
> my dead std box as it has an excellent input bearing.
a quick reply:
the 4 casings are all matched, you can't interchange them.
heat up the casing in boiling water and press out the bearing.