Post Reply

Gearbox repair or replace

Post by jorjford » Subscribing Member » Fri Jun 08, 2018 4:00 pm
Joined: Tue Mar 27, 2018 2:30 am
Posts: 10
I'm trying to source some parts but I'm not sure exactly what I need, except some help!
I got a motorhome with a wrecked gearbox. Some of the gears are broken so replacement parts are needed.
Symptoms are no reverse gear (bearing came out), very in noisy 1-3.
It also has an overdrive which has been disconenected. I would like to get that fixed too, but it's less important.
The quest to find the parts is not helped by their rarity, me not knowing which variety I have, sellers not knowing which variety they have and me not being able to tell either.


1. What gearbox have I got?

I was pretty sure it was the Vauxhall gearbox.

Reasons: It is a 4-speed gearbox with overdrive, which I believe wasn't available for ZF boxes.
Van is a 1983 97300 2.3 model (VIN: 97370 EV610906) which, according to my Haynes manual, all had the Vauxhall 4-Speed.
It's so wrecked I imagine it's the original one.

But then a mechanic who had a look said I was fortunate to have the short box as it's more common.
This confused me as I thought the ZF box was more common and shorter. So now I'm not so sure.


2. Swap or rebuild?

It looks like I can't get a replacement with the overdrive on it.
Can I take my one out, and put the overdrive on the replacement, and put that in?
Can I put in the replacement without putting the overdrive on?


3. What's wrong with the Overdrive?

The overdrive is disconnected and I have no idea why, but I imagine there is some kind of fault.
What are the most common reasons for this and would it be a big job to fix? Does it also need rare parts?


4. How to identify gearbox type from photos?

I've seen some gearboxes on eBay but the seller doesn't know what kind it is.
Some part numbers are visible but I haven't been able to find any info on them:

90088385
91011916
92005999

Re: Gearbox repair or replace

User avatar
Post by Phil Bradshaw » Club admin » Fri Jun 08, 2018 4:48 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3733
Best guide will be some photos of the offending transmission from underneath the van, both sides if possible.

If you can't persuade photos to upload to the forum then contact admin for assistance. :thumb:
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Gearbox repair or replace

Post by jorjford » Subscribing Member » Sat Jun 09, 2018 9:56 pm
Joined: Tue Mar 27, 2018 2:30 am
Posts: 10
From passenger side:
Image

Driver side:
Image

Hope those are clear enough, if not I could try again in daylight.

Re: Gearbox repair or replace

User avatar
Post by Phil Bradshaw » Club admin » Sun Jun 10, 2018 1:35 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3733
You have a Vauxhall 4-speed transmission with Laycock J type overdrive for CF models - the clincher is the flange at the front of the propellor shaft (car models have a sleeve yoke instead of a flange).

If your CF has the overdrive switch in the top of the gear shift lever then it may be original, in which case you should find Code 8064 or 8065 on the Service Parts Identification plate attached to the passenger door frame (lock side) or the vertical panel in the passenger foot well -

Image

If the chassis number (first row, left) starts with 971- then Code 8064 applies; if it starts 973- then Code 8065 applies. (4-character codes usually are the bottom row/s on the SPI plate.)

Noisy intermediate gears could be due to worn layshaft gear needle roller bearings, shaft and thrust washers, or worn mainshaft spigot bearing (and maybe worn shaft spigot too), or a combination; front and rear ball bearings may be worn out as well.

Reverse gear pinion has an integral plain bush; losing reverse gear may be due to a selector fault or too many teeth missing from the pinion, layshaft gear or 1st/2nd speed synchro sleeve in the reverse train.

Overdrive that is disconnected is an unknown quantity; there's a good chance that just wiring the thing properly is all that is needed to make it work.

Overdrive and its adaptor housing require a transmission mainshaft for overdrive which is completely different to the mainshaft in an ordinary 4-speed transmission: overdrive cannot be bolted to an ordinary 4-speed transmission. However, a 4-speed transmission is good order can be a donor for repairing an overdrive transmission as long as the overdrive and mainshaft for overdrive are serviceable.

Fitting an ordinary 4-speed transmission in place of the overdrive transmission will require a different front end for the propellor shaft (sleeve yoke and length difference). Speedometer cable for the overdrive will not fit an ordinary 4-speed transmission. I have a feeling that the rubber mounting is different too (one having studs where the other has holes for bolts).
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Gearbox repair or replace

Post by jorjford » Subscribing Member » Sun Jun 10, 2018 11:11 pm
Joined: Tue Mar 27, 2018 2:30 am
Posts: 10
Thanks for all the excellent information! :thumb:
I suppose the easiest thing will be to get another box for parts then, and get mine repaired. Then just cross my fingers for the overdrive.

The overdrive switch is where you described, but the matching code isn't there on the SPI plate :|

Re: Gearbox repair or replace

User avatar
Post by Phil Bradshaw » Club admin » Sun Jun 10, 2018 11:29 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3733
Finding a suitable donor may take some time unless you're very lucky so be sure to keep the transmission oil topped up meanwhile!

Sounds like you have all CF kit for the overdrive which is a plus. Not having a corresponding SVOS code just means it wasn't fitted at the factory, e.g. added before delivery by or for the body manufacturer so only appearing in their paperwork, not on the SPI plate.
  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Post Reply

Return to “Manual transmission”