5 speed gearbox noise & related issues

[JamesD]

First posting from a forum novice with a 1980 TR7v8 (and a mechanical novice as well)

 

Increasing problem with what can best be described as 'grinding' noises - evident in all gears bar fifth and worse when gearbox cold. All gears are useable but when in gear grinding / cog noises can be heard, almost as if the adajcent gear is too close to the one being used (this shows my technical side). Problem can be substantially cured when in gear by applying applying pressure on the gear change to the right (towards you as the driver) and substantially worsened by pressure to the left. This solution not practical when you need two hands for other things. No noises when in neutral and no particular problem with the gearchange itself.

 

Anyone any ideas or am I best to opt for a reconditioned gearbox?

 

Probably unrelated but the speedometer has also stopped working - bought a new cable but easy to fit without access to a lift.

 

Any suggestions for a sympathetic garage in the SW Surrey area?

[martynharrison]

The LT77 gearbox is renowned for wearing out and being out of kilter due largely to the needle rollers in the end. There's lots about in breakers yards from a variety of vehicles but the TR7 5 speed is usually less worn than the v8 versions of SD1 and various vans, on account of it being driven by a four pot engine.

 

I'd recommend changing the gear oil and seeing if that helps, bunging sawdust into it is a cheap and nasty way to keep it going towards the end, and when the box is scrap you can get another easily enough. Most TR7s are used infrequently so the box can be lived with and they seem to go on indefinitely if you can live with the symptoms.

 

To solve the problem with money, RPI are willing to sell you a direct replacement box with modern smoothness, dunno how much and they're perfectionists to some extent as a rattly old box will work well enough regardless.

[jrv8]

Hi,

Bunging sawdust into the box as the prevoius post is hinting at, will kill it stone dead in a very short space of time as it will either clog the oil pump or shear off the nylon teeth on the pump gears. NOT a good idea.

 

Before you do anything too drastic, check that your remote control bushes aren't worn out. When these let go they allow the back of the remote control to touch the propshaft and it makes a real grinding noise. Holding the gearstick forwards or to the one side can sometimes clear the noise as it filts the remote away from the propshaft.

These can easily be checked from underneathn the car.

 

Hope this helps

Jim

Edited October 26, 2006 by jrv8

[anthonyt]

im with Jim its either the shifter or you need to rebuild the box even too heavy an oil will make things worse so the sawdust is definetly out.

[JamesD]

Thanks for the suggestions on the cause of my geabox noise. I have experimented and concluded that it is almost certainly the remote control bushes that are worn and that the noise is the back of the remote control coming into contact with the propshaft - thanks to Jim for this. By applying upward pressure to the gear lever, I can virtually cure the problem. Having looked in the Rimmer catalogue, I am not quite sure what part number the bushes are and whether it would be sensible to change any other parts at the same time. Can anyone help me with this?

 

James D

[mikehardwick]

James

 

Give the guys at S&S Preparations a ring (see supliers links) - they are always prepared to help, and can probably suply the parts too!

 

Mike

Edited November 10, 2006 by mikehardwick

[malcolm]

Mike is right. S&S or Robsport will be able to supply the bushes from your description - not necessary to research the part numbers. I can't think of anything else to replace when removing the remote / renewing the bushes.

 

Malcolm.

[big rumbly]

James, I can confirm, that the noise can come from the remote hitting the prop, as a temporary measure I fitted a heavy duty cable tie round the remote and fixed it to the transmission tunnel,(can be done from inside the car) that temporary fix is now 2 years old.